Android 中的menu

 

Android中menu可分为两种，分别为options menu(menu键产生), context menu(长按屏幕产生)

下面举个例子;

1,options menu(menu键产生),

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     @Override

     public boolean onCreateOptionsMenu(Menu menu) {

         m=menu;

         menu.add(0, Menu.FIRST, 0, "1st");

         menu.add(0, Menu.FIRST+1, 0, "2st");

         menu.add(0, Menu.FIRST+2, 0, "3st");

         menu.add(0, Menu.FIRST+3, 0, "4st");

         return super.onCreateOptionsMenu(menu);

     }

    

     @Override

     public boolean onOptionsItemSelected(MenuItem item) {

         switch (item.getItemId()) { 

         case 1:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

         case 2:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

         case 3:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

         case 4:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

         }

         return super.onOptionsItemSelected(item);

     }

 

 

注意：public boolean onCreateOptionsMenu(Menu menu)方法只被系统调用一次，如需要动态更改菜单内容还需重写onPrepareOptionsMenu(Menu menu)方法实现

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Menu m=null;

     int count=0;

    

      @Override

     public boolean onPrepareOptionsMenu(Menu menu) {

        

         if(count>0){

              if(count%2==0){

                  menu.removeGroup(1);

              }else{

                  menu.add(1, Menu.FIRST, 0, "5st");

                  menu.add(1, Menu.FIRST+1, 0, "6st");

              }

         }

         count++;

         return super.onPrepareOptionsMenu(menu);

     }

 

2,context menu(长按屏幕产生)

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@Override

     public boolean onContextItemSelected(MenuItem item) {

    switch (item.getItemId()) { 

    case 1:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

         case 2:

              Toast.makeText(this, "you select"+item.getItemId(), 500).show();

              break;

    }

         return super.onContextItemSelected(item);

     }

 

     @Override

     public void onCreateContextMenu(ContextMenu menu, View v,

              ContextMenuInfo menuInfo) {

         menu.add(0, Menu.FIRST, 0, "1st");

         menu.add(0, Menu.FIRST+1, 0, "2st");

         super.onCreateContextMenu(menu, v, menuInfo);

         }

 

 

@Override

  public boolean onContextItemSelected(MenuItem item) {

      switch (item.getItemId()) { 

      case 1:

     Toast.makeText(this, "you select"+item.getItemId(), 500).show();

     break;

    case 2:

     Toast.makeText(this, "you select"+item.getItemId(), 500).show();

     break;

      }

    return super.onContextItemSelected(item);

  }

 

  @Override

  public void onCreateContextMenu(ContextMenu menu, View v,

     ContextMenuInfo menuInfo) {

    menu.add(0, Menu.FIRST, 0, "1st");

    menu.add(0, Menu.FIRST+1, 0, "2st");

    super.onCreateContextMenu(menu, v, menuInfo);

  }

还有一步，与View进行绑定；

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/** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

     //   setContentView(R.layout.main);

        MyView my=new MyView(this);

        setContentView(my);

        registerForContextMenu(my);

}

/** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

     //   setContentView(R.layout.main);

        MyView my=new MyView(this);

        setContentView(my);

        registerForContextMenu(my);

    }

 

以上是通过代码实现，还可以通过xml文件实现

menu.xml 内容如下；

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<menu xmlns:android="http://schemas./apk/res/android">

 

  

    <item android:id="@+id/fourth_item"

        android:orderInCategory="3"

        android:title="Fourth" />

 

    <item android:id="@+id/third_item"

        android:orderInCategory="2"

        android:title="Third" />

 

    <item android:id="@+id/dive"

        android:orderInCategory="1"

        android:title="Second" />

 

    <item android:id="@+id/jump"

        android:orderInCategory="0"

        android:title="First" />

 

</menu><menu xmlns:android="http://schemas./apk/res/android">

 

  

    <item android:id="@+id/fourth_item"

        android:orderInCategory="3"

        android:title="Fourth" />

 

    <item android:id="@+id/third_item"

        android:orderInCategory="2"

        android:title="Third" />

 

    <item android:id="@+id/dive"

        android:orderInCategory="1"

        android:title="Second" />

 

    <item android:id="@+id/jump"

        android:orderInCategory="0"

        android:title="First" />

 

</menu>

加载xml文件；

 

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@Override

    public boolean onCreateOptionsMenu(Menu menu) {

      

        // Inflate the currently selected menu XML resource.

        MenuInflater inflater = getMenuInflater();

        inflater.inflate(sMenuExampleResources[R.m], menu);

       

       

        return true;

    }

 

 @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {

                             

            case R.id.jump:

                Toast.makeText(this, "Jump up in the air!", Toast.LENGTH_SHORT).show();

                return true;

 

            case R.id.dive:

                Toast.makeText(this, "Dive into the water!", Toast.LENGTH_SHORT).show();

     return false;

}