标签:android 前言 很多时候我们都在刷微博或者微信朋友圈的时候都会看到很多图片,而这些图片的显示跟我们平时很多控件的显示方式都不一样,而且,当我们仔细去观察后就会发现,他加载的图片都是根据图片数量动态加载的,根据不同的图片数量来用不同的布局显示 当图片是4张的时候,就会形成一个2x2的正方形,除了一张的情况,另外的都是按照九宫格的方式显示和排列图片的。那么这种布局是怎么实现的呢,一开始,好多人都可能认为用原生的GridView就能搞掂,但是,却有几种特殊的情况是GridView解决不了的,例如4张图片的情况,或者1张,其实也可以根据图片的数量然后用几个不同布局的GridView来实现,不过那样的话就复杂得多了。而且处理起来很麻烦,其实,大部分的实现都是通过自定义ViewGroup来实现的,通过代码编写来设定childrenView的layout来实现这种布局,而NineGridView控件就是这么一个东西,代码其实很简单,100行就够了。 代码编写 先自定义一个View集成ViewGroup,编辑器会提示你实现OnLayout方法,实现之,这里我们动态的添加的话其实不用到OnLayout方法,自定义一个layoutChildrenView()用来为子view设定位置就行了,该方法的实现如下: int childrenCount = listData.size(); int singleWidth = (totalWidth - gap * (3 - 1)) / 3; int singleHeight = singleWidth; //根据子view数量确定高度 ViewGroup.LayoutParams params = getLayoutParams(); params.height = singleHeight * rows + gap * (rows - 1); setLayoutParams(params); for (int i = 0; i < childrenCount; i++) { CustomImageView childrenView = (CustomImageView) getChildAt(i); childrenView.setImageUrl(((Image) listData.get(i)).getUrl()); int[] position = findPosition(i); int left = (singleWidth + gap) * position[1]; int top = (singleHeight + gap) * position[0]; int right = left + singleWidth; int bottom = top + singleHeight; } } 复制代码 添加一个设置图片资源的接口,一般情况下我们都是用在listview来显示数据,而数据都是封装好的,这里提供一个Image封装类,接口和封装类代码如下: public void setImagesData(List<Image> lists) { if (lists == null || lists.isEmpty()) { return; } //初始化布局 generateChildrenLayout(lists.size()); //这里做一个重用view的处理 if (listData == null) { int i = 0; while (i < lists.size()) { CustomImageView iv = generateImageView(); addView(iv,generateDefaultLayoutParams()); i++; } } else { int oldViewCount = listData.size(); int newViewCount = lists.size(); if (oldViewCount > newViewCount) { removeViews(newViewCount - 1, oldViewCount - newViewCount); } else if (oldViewCount < newViewCount) { for (int i = 0; i < newViewCount - oldViewCount; i++) { CustomImageView iv = generateImageView(); addView(iv,generateDefaultLayoutParams()); } } } listData = lists; } 复制代码 Image封装类: public class Image { private String url; private int width; private int height; public Image(String url, int width, int height) { this.url = url; this.width = width; this.height = height; L.i(toString()); } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public int getWidth() { return width; } public void setWidth(int width) { this.width = width; } public int getHeight() { return height; } public void setHeight(int height) { this.height = height; } @Override public String toString() { return 'image---->>url='+url+'width='+width+'height'+height; } } 复制代码 /** * 根据图片个数确定行列数量 * 对应关系如下 * num row column * 1 1 1 * 2 1 2 * 3 1 3 * 4 2 2 * 5 2 3 * 6 2 3 * 7 3 3 * 8 3 3 * 9 3 3 * * @param length */ private void generateChildrenLayout(int length) { if (length <= 3) { rows = 1; columns = length; } else if (length <= 6) { rows = 2; columns = 3; if (length == 4) { columns = 2; } } else { rows = 3; columns = 3; } } 复制代码 这些,就是NineGridLayout的核心代码了,是不是很简单,整个类的源码如下: package com.weixinninegridlayout; import android.content.Context; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import java.util.List; /** * Created by Pan_ on 2015/2/2. */ public class NineGridlayout extends ViewGroup { /** * 图片之间的间隔 */ private int gap = 5; private int columns;// private int rows;// private List listData; private int totalWidth; public NineGridlayout(Context context) { super(context); } public NineGridlayout(Context context, AttributeSet attrs) { super(context, attrs); ScreenTools screenTools=ScreenTools.instance(getContext()); totalWidth=screenTools.getScreenWidth()-screenTools.dip2px(80); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { } int childrenCount = listData.size(); int singleWidth = (totalWidth - gap * (3 - 1)) / 3; int singleHeight = singleWidth; //根据子view数量确定高度 ViewGroup.LayoutParams params = getLayoutParams(); params.height = singleHeight * rows + gap * (rows - 1); setLayoutParams(params); for (int i = 0; i < childrenCount; i++) { CustomImageView childrenView = (CustomImageView) getChildAt(i); childrenView.setImageUrl(((Image) listData.get(i)).getUrl()); int[] position = findPosition(i); int left = (singleWidth + gap) * position[1]; int top = (singleHeight + gap) * position[0]; int right = left + singleWidth; int bottom = top + singleHeight; } } private int[] findPosition(int childNum) { int[] position = new int[2]; for (int i = 0; i < rows; i++) { for (int j = 0; j < columns; j++) { if ((i * columns + j) == childNum) { position[0] = i;//行 position[1] = j;//列 break; } } } return position; } public int getGap() { return gap; } public void setGap(int gap) { this.gap = gap; } public void setImagesData(List<Image> lists) { if (lists == null || lists.isEmpty()) { return; } //初始化布局 generateChildrenLayout(lists.size()); //这里做一个重用view的处理 if (listData == null) { int i = 0; while (i < lists.size()) { CustomImageView iv = generateImageView(); addView(iv,generateDefaultLayoutParams()); i++; } } else { int oldViewCount = listData.size(); int newViewCount = lists.size(); if (oldViewCount > newViewCount) { removeViews(newViewCount - 1, oldViewCount - newViewCount); } else if (oldViewCount < newViewCount) { for (int i = 0; i < newViewCount - oldViewCount; i++) { CustomImageView iv = generateImageView(); addView(iv,generateDefaultLayoutParams()); } } } listData = lists; } /** * 根据图片个数确定行列数量 * 对应关系如下 * num row column * 1 1 1 * 2 1 2 * 3 1 3 * 4 2 2 * 5 2 3 * 6 2 3 * 7 3 3 * 8 3 3 * 9 3 3 * * @param length */ private void generateChildrenLayout(int length) { if (length <= 3) { rows = 1; columns = length; } else if (length <= 6) { rows = 2; columns = 3; if (length == 4) { columns = 2; } } else { rows = 3; columns = 3; } } private CustomImageView generateImageView() { CustomImageView iv = new CustomImageView(getContext()); iv.setScaleType(ImageView.ScaleType.CENTER_CROP); iv.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { } }); iv.setBackgroundColor(Color.parseColor('#f5f5f5')); return iv; } } 复制代码 因为微信那些图片在点击的时候是有一个灰色的蒙版的,实现起来其实很简单,我们这里在自定义一个imageview,叫做CustomImageView,复写onTouchEvent方法,在onKeyDown的时候添加一个colorfilter,然后再onKeyUp的时候clear掉,这样就实现了点击有灰色蒙版的效果,同时为了方便项目加载图片的解耦,我加载图片用了picasso这个开源库,这个开源库的地址为点击打开链接 ,具体的代码如下: package com.weixinninegridlayout; import android.content.Context; import android.graphics.Color; import android.graphics.PorterDuff; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.text.TextUtils; import android.util.AttributeSet; import android.view.MotionEvent; import android.widget.ImageView; import com.squareup.picasso.Picasso; /** * Created by Pan_ on 2015/2/2. */ public class CustomImageView extends ImageView { private String url; private boolean isAttachedToWindow; public CustomImageView(Context context, AttributeSet attrs) { super(context, attrs); } public CustomImageView(Context context) { super(context); } @Override public boolean onTouchEvent(MotionEvent event) { case MotionEvent.ACTION_DOWN: Drawable drawable=getDrawable(); if(drawable!=null) { drawable.mutate().setColorFilter(Color.GRAY, PorterDuff.Mode.MULTIPLY); } break; case MotionEvent.ACTION_MOVE: break; case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: Drawable drawableUp=getDrawable(); if(drawableUp!=null) { drawableUp.mutate().clearColorFilter(); } break; } return super.onTouchEvent(event); } @Override public void onAttachedToWindow() { isAttachedToWindow = true; setImageUrl(url); super.onAttachedToWindow(); } @Override public void onDetachedFromWindow() { Picasso.with(getContext()).cancelRequest(this); isAttachedToWindow = false; setImageBitmap(null); super.onDetachedFromWindow(); } public void setImageUrl(String url) { if (!TextUtils.isEmpty(url)) { this.url = url; if (isAttachedToWindow) { Picasso.with(getContext()).load(url).placeholder(new ColorDrawable(Color.parseColor('#f5f5f5'))).into(this); } } } } 源码要的留言 标签:android
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