三种实现Android主界面Tab的方式

在平时的Android开发中，我们经常会使用Tab来进行主界面的布局。由于手机屏幕尺寸的限制，合理使用Tab可以极大的利用屏幕资源，给用户带来良好的体验。学会Tab的使用方法已经成为学习Android开发必不可少的技能了。我们经常使用的微信、QQ就是使用Tab的方式进行主界面的布局的。

下面我们通过三种方式实现旧版的微信以演示Tab的使用方式。

最终效果：

第一种：单纯使用ViewPager

MainActivity.java

public class MainActivity extends Activity implements OnClickListener {
    //声明ViewPager
    private ViewPager mViewpager;

    //声明四个Tab
    private LinearLayout mTabWeixin;
    private LinearLayout mTabFrd;
    private LinearLayout mTabAddress;
    private LinearLayout mTabSetting;

    //声明四个ImageButton
    private ImageButton mWeixinImg;
    private ImageButton mFrdImg;
    private ImageButton mAddressImg;
    private ImageButton mSettingImg;

    //声明ViewPager的适配器
    private PagerAdapter mAdpater;
    //用于装载四个Tab的List
    private List<View> mTabs = new ArrayList<View>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //去掉TitleBar
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        initViews();//初始化控件
        initDatas();//初始化数据
        initEvents();//初始化事件

    }

    private void initEvents() {
        //设置四个Tab的点击事件
        mTabWeixin.setOnClickListener(this);
        mTabFrd.setOnClickListener(this);
        mTabAddress.setOnClickListener(this);
        mTabSetting.setOnClickListener(this);

        //添加ViewPager的切换Tab的监听事件
        mViewpager.addOnPageChangeListener(new OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                //获取ViewPager的当前Tab
                int currentItem = mViewpager.getCurrentItem();
                //将所以的ImageButton设置成灰色
                resetImgs();
                //将当前Tab对应的ImageButton设置成绿色
                switch (currentItem) {
                    case 0:
                        mWeixinImg.setImageResource(R.mipmap.tab_weixin_pressed);
                        break;
                    case 1:
                        mFrdImg.setImageResource(R.mipmap.tab_find_frd_pressed);
                        break;
                    case 2:
                        mAddressImg.setImageResource(R.mipmap.tab_address_pressed);
                        break;
                    case 3:
                        mSettingImg.setImageResource(R.mipmap.tab_settings_pressed);
                        break;
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

    private void initDatas() {
        //初始化ViewPager的适配器
        mAdpater = new PagerAdapter() {
            @Override
            public int getCount() {
                return mTabs.size();
            }

            @Override
            public boolean isViewFromObject(View view, Object object) {
                return view == object;
            }

            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                View view = mTabs.get(position);
                container.addView(view);
                return view;
            }

            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView(mTabs.get(position));
            }
        };
        //设置ViewPager的适配器
        mViewpager.setAdapter(mAdpater);
    }

    //初始化控件
    private void initViews() {
        mViewpager = (ViewPager) findViewById(R.id.id_viewpager);

        mTabWeixin = (LinearLayout) findViewById(R.id.id_tab_weixin);
        mTabFrd = (LinearLayout) findViewById(R.id.id_tab_frd);
        mTabAddress = (LinearLayout) findViewById(R.id.id_tab_address);
        mTabSetting = (LinearLayout) findViewById(R.id.id_tab_setting);

        mWeixinImg = (ImageButton) findViewById(R.id.id_tab_weixin_img);
        mFrdImg = (ImageButton) findViewById(R.id.id_tab_frd_img);
        mAddressImg = (ImageButton) findViewById(R.id.id_tab_address_img);
        mSettingImg = (ImageButton) findViewById(R.id.id_tab_setting_img);

        //获取到四个Tab
        LayoutInflater inflater = LayoutInflater.from(this);
        View tab1 = inflater.inflate(R.layout.tab1, null);
        View tab2 = inflater.inflate(R.layout.tab2, null);
        View tab3 = inflater.inflate(R.layout.tab3, null);
        View tab4 = inflater.inflate(R.layout.tab4, null);

        //将四个Tab添加到集合中
        mTabs.add(tab1);
        mTabs.add(tab2);
        mTabs.add(tab3);
        mTabs.add(tab4);

    }

    @Override
    public void onClick(View v) {
        //先将四个ImageButton都设置成灰色
        resetImgs();
        switch (v.getId()) {
            case R.id.id_tab_weixin:
                //设置viewPager的当前Tab
                mViewpager.setCurrentItem(0);
                //将当前Tab对应的ImageButton设置成绿色
                mWeixinImg.setImageResource(R.mipmap.tab_weixin_pressed);
                break;
            case R.id.id_tab_frd:
                mViewpager.setCurrentItem(1);
                mFrdImg.setImageResource(R.mipmap.tab_find_frd_pressed);
                break;
            case R.id.id_tab_address:
                mViewpager.setCurrentItem(2);
                mAddressImg.setImageResource(R.mipmap.tab_address_pressed);
                break;
            case R.id.id_tab_setting:
                mViewpager.setCurrentItem(3);
                mSettingImg.setImageResource(R.mipmap.tab_settings_pressed);
                break;
        }
    }

    //将四个ImageButton设置成灰色
    private void resetImgs () {
        mWeixinImg.setImageResource(R.mipmap.tab_weixin_normal);
        mFrdImg.setImageResource(R.mipmap.tab_find_frd_normal);
        mAddressImg.setImageResource(R.mipmap.tab_address_normal);
        mSettingImg.setImageResource(R.mipmap.tab_settings_normal);
    }
}

顶部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:background="@android:drawable/title_bar"
              android:gravity="center"
              android:layout_width="match_parent"
              android:layout_height="45dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="微信"
        android:textColor="#ffffff"
        android:textSize="20sp"
        android:textStyle="bold"/>

</LinearLayout>

top.xml

四个Tab对应页面的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Weixin Tab!"/>
</LinearLayout>

tab1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Friend Tab!"/>
</LinearLayout>

tab2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Address Tab!"/>
</LinearLayout>

tab3.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Setting Tab!"/>
</LinearLayout>

tab4.xml

底部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="55dp"
              android:gravity="center"
              android:background="@color/material_blue_grey_800"
              android:orientation="horizontal">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:id="@+id/id_tab_weixin"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_weixin_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_weixin_pressed"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="微信"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_frd"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_frd_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_find_frd_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="朋友"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_address"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_address_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_address_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="通讯录"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_setting"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_setting_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_settings_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="设置"/>
    </LinearLayout>

</LinearLayout>

bottom.xml

主布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas./apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <include layout="@layout/top"/>

    <android.support.v4.view.ViewPager
        android:id="@+id/id_viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

    </android.support.v4.view.ViewPager>

    <include layout="@layout/bottom"/>
</LinearLayout>

activity_main.xml

完整源码 : 点击下载

单纯使用ViewPager的方式可以实现左右滑动切换页面和点击Tab切换页面的效果。但是大家发现，这种方式需要在Activity完成所有的代码实现，包括初始化Tab及其对应页面的初始化控件、数据、事件及业务逻辑的处理。这样会使得Activity看起来非常臃肿，进而造成代码的可读性和可维护性变得极差。

谷歌在Android 3.0时推出了Fragment。可以分别使用Fragment来管理每个Tab对应的页面的布局及功能的实现。然后将Fragment与Android关联，这样Android只需要管理Fragment就行了，起到了调度器的作用，不再关心每个Fragment里的内容及功能实现是什么。这样就极大的解放了Activity，使代码变得简单、易读。

下面我们通过使用Fragment的方式来实现Tab。

第二种：单纯使用Fragment

MainActivity.java

public class MainActivity extends FragmentActivity implements OnClickListener {
    //声明四个Tab的布局文件
    private LinearLayout mTabWeixin;
    private LinearLayout mTabFrd;
    private LinearLayout mTabAddress;
    private LinearLayout mTabSetting;

    //声明四个Tab的ImageButton
    private ImageButton mWeixinImg;
    private ImageButton mFrdImg;
    private ImageButton mAddressImg;
    private ImageButton mSettingImg;

    //声明四个Tab分别对应的Fragment
    private Fragment mFragWeinxin;
    private Fragment mFragFrd;
    private Fragment mFragAddress;
    private Fragment mFragSetting;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        initViews();//初始化控件
        initEvents();//初始化事件
        selectTab(0);//默认选中第一个Tab
    }

    private void initEvents() {
        //初始化四个Tab的点击事件
        mTabWeixin.setOnClickListener(this);
        mTabFrd.setOnClickListener(this);
        mTabAddress.setOnClickListener(this);
        mTabSetting.setOnClickListener(this);
    }

    private void initViews() {
        //初始化四个Tab的布局文件
        mTabWeixin = (LinearLayout) findViewById(R.id.id_tab_weixin);
        mTabFrd = (LinearLayout) findViewById(R.id.id_tab_frd);
        mTabAddress = (LinearLayout) findViewById(R.id.id_tab_address);
        mTabSetting = (LinearLayout) findViewById(R.id.id_tab_setting);

        //初始化四个ImageButton
        mWeixinImg = (ImageButton) findViewById(R.id.id_tab_weixin_img);
        mFrdImg = (ImageButton) findViewById(R.id.id_tab_frd_img);
        mAddressImg = (ImageButton) findViewById(R.id.id_tab_address_img);
        mSettingImg = (ImageButton) findViewById(R.id.id_tab_setting_img);
    }

    //处理Tab的点击事件
    @Override
    public void onClick(View v) {
        //先将四个ImageButton置为灰色
        resetImgs();
        switch (v.getId()) {
            case R.id.id_tab_weixin:
                selectTab(0);//当点击的是微信的Tab就选中微信的Tab
                break;
            case R.id.id_tab_frd:
                selectTab(1);
                break;
            case R.id.id_tab_address:
                selectTab(2);
                break;
            case R.id.id_tab_setting:
                selectTab(3);
                break;
        }

    }

    //进行选中Tab的处理
    private void selectTab(int i) {
        //获取FragmentManager对象
        FragmentManager manager = getSupportFragmentManager();
        //获取FragmentTransaction对象
        FragmentTransaction transaction = manager.beginTransaction();
        //先隐藏所有的Fragment
        hideFragments(transaction);
        switch (i) {
            //当选中点击的是微信的Tab时
            case 0:
                //设置微信的ImageButton为绿色
                mWeixinImg.setImageResource(R.mipmap.tab_weixin_pressed);
                //如果微信对应的Fragment没有实例化，则进行实例化，并显示出来
                if (mFragWeinxin == null) {
                    mFragWeinxin = new WeixinFragment();
                    transaction.add(R.id.id_content, mFragWeinxin);
                } else {
                    //如果微信对应的Fragment已经实例化，则直接显示出来
                    transaction.show(mFragWeinxin);
                }
                break;
            case 1:
                mFrdImg.setImageResource(R.mipmap.tab_find_frd_pressed);
                if (mFragFrd == null) {
                    mFragFrd = new FrdFragment();
                    transaction.add(R.id.id_content, mFragFrd);
                } else {
                    transaction.show(mFragFrd);
                }
                break;
            case 2:
                mAddressImg.setImageResource(R.mipmap.tab_address_pressed);
                if (mFragAddress == null) {
                    mFragAddress = new AddressFragment();
                    transaction.add(R.id.id_content, mFragAddress);
                } else {
                    transaction.show(mFragAddress);
                }
                break;
            case 3:
                mSettingImg.setImageResource(R.mipmap.tab_settings_pressed);
                if (mFragSetting == null) {
                    mFragSetting = new SettingFragment();
                    transaction.add(R.id.id_content, mFragSetting);
                } else {
                    transaction.show(mFragSetting);
                }
                break;
        }
        //不要忘记提交事务
        transaction.commit();
    }

    //将四个的Fragment隐藏
    private void hideFragments(FragmentTransaction transaction) {
        if (mFragWeinxin != null) {
            transaction.hide(mFragWeinxin);
        }
        if (mFragFrd != null) {
            transaction.hide(mFragFrd);
        }
        if (mFragAddress != null) {
            transaction.hide(mFragAddress);
        }
        if (mFragSetting != null) {
            transaction.hide(mFragSetting);
        }
    }

    //将四个ImageButton置为灰色
    private void resetImgs() {
        mWeixinImg.setImageResource(R.mipmap.tab_weixin_normal);
        mFrdImg.setImageResource(R.mipmap.tab_find_frd_normal);
        mAddressImg.setImageResource(R.mipmap.tab_address_normal);
        mSettingImg.setImageResource(R.mipmap.tab_settings_normal);
    }
}

“微信”、“朋友”、“通讯录”、“设置”所对应的Fragment

public class WeixinFragment extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab1, container, false);
        return view;
    }
}

WeixinFragment.java

public class FrdFragment extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab2, container, false);
        return view;
    }
}

FrdFragment.java

public class AddressFragment extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab3, container, false);
        return view;
    }
}

AddressFragment.java

public class SettingFragment extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab4, container, false);
        return view;
    }
}

SettingFragment.java

顶部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:background="@android:drawable/title_bar"
              android:gravity="center"
              android:layout_width="match_parent"
              android:layout_height="45dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="微信"
        android:textColor="#ffffff"
        android:textSize="20sp"
        android:textStyle="bold"/>

</LinearLayout>

top.xml

四个Tab对应页面的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Weixin Tab!"/>
</LinearLayout>

tab1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Friend Tab!"/>
</LinearLayout>

tab2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Address Tab!"/>
</LinearLayout>

tab3.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Setting Tab!"/>
</LinearLayout>

tab4.xml

底部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="55dp"
              android:gravity="center"
              android:background="@color/material_blue_grey_800"
              android:orientation="horizontal">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:id="@+id/id_tab_weixin"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_weixin_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_weixin_pressed"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="微信"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_frd"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_frd_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_find_frd_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="朋友"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_address"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_address_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_address_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="通讯录"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_setting"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_setting_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_settings_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="设置"/>
    </LinearLayout>

</LinearLayout>

bottom.xml

主布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas./apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <include layout="@layout/top"/>

    <FrameLayout
        android:id="@+id/id_content"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

    </FrameLayout>

    <include layout="@layout/bottom"/>
</LinearLayout>

activity_main.xml

完整源码 : 点击下载

可以看出，使用Fragment实现了Activity与Tab对应的页面分离，特别是当Tab对应的页面的布局和逻辑比较复杂时更能体会到使用Fragment的好处。但是单纯使用Fragment只能通过点击Tab来切换页面，并不能实现左右滑动进行切换。

下面我们通过使用 ViewPager + Fragment 的方式实现Tab，这也是开发中使用比较广泛的一种方式。

第三种：使用 ViewPager + Fragment

MainActivity.java

public class MainActivity extends FragmentActivity implements OnClickListener {
    //声明ViewPager
    private ViewPager mViewPager;
    //适配器
    private FragmentPagerAdapter mAdapter;
    //装载Fragment的集合
    private List<Fragment> mFragments;

    //四个Tab对应的布局
    private LinearLayout mTabWeixin;
    private LinearLayout mTabFrd;
    private LinearLayout mTabAddress;
    private LinearLayout mTabSetting;

    //四个Tab对应的ImageButton
    private ImageButton mImgWeixin;
    private ImageButton mImgFrd;
    private ImageButton mImgAddress;
    private ImageButton mImgSetting;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        initViews();//初始化控件
        initEvents();//初始化事件
        initDatas();//初始化数据
    }

    private void initDatas() {
        mFragments = new ArrayList<>();
        //将四个Fragment加入集合中
        mFragments.add(new WeixinFragment());
        mFragments.add(new FrdFragment());
        mFragments.add(new AddressFragment());
        mFragments.add(new SettingFragment());

        //初始化适配器
        mAdapter = new FragmentPagerAdapter(getSupportFragmentManager()) {
            @Override
            public Fragment getItem(int position) {//从集合中获取对应位置的Fragment
                return mFragments.get(position);
            }

            @Override
            public int getCount() {//获取集合中Fragment的总数
                return mFragments.size();
            }

        };
        //不要忘记设置ViewPager的适配器
        mViewPager.setAdapter(mAdapter);
        //设置ViewPager的切换监听
        mViewPager.addOnPageChangeListener(new OnPageChangeListener() {
            @Override
            //页面滚动事件
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            //页面选中事件
            @Override
            public void onPageSelected(int position) {
                //设置position对应的集合中的Fragment
                mViewPager.setCurrentItem(position);
                resetImgs();
                selectTab(position);
            }

            @Override
            //页面滚动状态改变事件
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

    private void initEvents() {
        //设置四个Tab的点击事件
        mTabWeixin.setOnClickListener(this);
        mTabFrd.setOnClickListener(this);
        mTabAddress.setOnClickListener(this);
        mTabSetting.setOnClickListener(this);

    }

    //初始化控件
    private void initViews() {
        mViewPager = (ViewPager) findViewById(R.id.id_viewpager);

        mTabWeixin = (LinearLayout) findViewById(R.id.id_tab_weixin);
        mTabFrd = (LinearLayout) findViewById(R.id.id_tab_frd);
        mTabAddress = (LinearLayout) findViewById(R.id.id_tab_address);
        mTabSetting = (LinearLayout) findViewById(R.id.id_tab_setting);

        mImgWeixin = (ImageButton) findViewById(R.id.id_tab_weixin_img);
        mImgFrd = (ImageButton) findViewById(R.id.id_tab_frd_img);
        mImgAddress = (ImageButton) findViewById(R.id.id_tab_address_img);
        mImgSetting = (ImageButton) findViewById(R.id.id_tab_setting_img);

    }

    @Override
    public void onClick(View v) {
        //先将四个ImageButton置为灰色
        resetImgs();

        //根据点击的Tab切换不同的页面及设置对应的ImageButton为绿色
        switch (v.getId()) {
            case R.id.id_tab_weixin:
                selectTab(0);
                break;
            case R.id.id_tab_frd:
                selectTab(1);
                break;
            case R.id.id_tab_address:
                selectTab(2);
                break;
            case R.id.id_tab_setting:
                selectTab(3);
                break;
        }
    }

    private void selectTab(int i) {
        //根据点击的Tab设置对应的ImageButton为绿色
        switch (i) {
            case 0:
                mImgWeixin.setImageResource(R.mipmap.tab_weixin_pressed);
                break;
            case 1:
                mImgFrd.setImageResource(R.mipmap.tab_find_frd_pressed);
                break;
            case 2:
                mImgAddress.setImageResource(R.mipmap.tab_address_pressed);
                break;
            case 3:
                mImgSetting.setImageResource(R.mipmap.tab_settings_pressed);
                break;
        }
        //设置当前点击的Tab所对应的页面
        mViewPager.setCurrentItem(i);
    }

    //将四个ImageButton设置为灰色
    private void resetImgs() {
        mImgWeixin.setImageResource(R.mipmap.tab_weixin_normal);
        mImgFrd.setImageResource(R.mipmap.tab_find_frd_normal);
        mImgAddress.setImageResource(R.mipmap.tab_address_normal);
        mImgSetting.setImageResource(R.mipmap.tab_settings_normal);
    }
}

“微信”、“朋友”、“通讯录”、“设置”所对应的Fragment

public class WeixinFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab1, container, false);
        return view;
    }
}

WeixinFragment.java

public class FrdFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab2, container, false);
        return view;
    }
}

FrdFragment.java

public class AddressFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab3, container, false);
        return view;
    }
}

AddressFragment.java

public class SettingFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.tab4, container, false);
        return view;
    }
}

SettingFragment.java

顶部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:background="@android:drawable/title_bar"
              android:gravity="center"
              android:layout_width="match_parent"
              android:layout_height="45dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="微信"
        android:textColor="#ffffff"
        android:textSize="20sp"
        android:textStyle="bold"/>

</LinearLayout>

top.xml

四个Tab对应页面的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Weixin Tab!"/>
</LinearLayout>

tab1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Friend Tab!"/>
</LinearLayout>

tab2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Address Tab!"/>
</LinearLayout>

tab3.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="30sp"
        android:text="The Setting Tab!"/>
</LinearLayout>

tab4.xml

底部布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas./apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="55dp"
              android:gravity="center"
              android:background="@color/material_blue_grey_800"
              android:orientation="horizontal">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:id="@+id/id_tab_weixin"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_weixin_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_weixin_pressed"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="微信"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_frd"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_frd_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_find_frd_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="朋友"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_address"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_address_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_address_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="通讯录"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/id_tab_setting"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageButton
            android:id="@+id/id_tab_setting_img"
            android:clickable="false"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/tab_settings_normal"
            android:background="#00000000"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:text="设置"/>
    </LinearLayout>

</LinearLayout>

bottom.xml

主布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas./apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <include layout="@layout/top"/>

    <android.support.v4.view.ViewPager
        android:id="@+id/id_viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

    </android.support.v4.view.ViewPager>

    <include layout="@layout/bottom"/>
</LinearLayout>

activity_main.xml