ContextMenu菜单的介绍

　　ContextMenu是支持长点击，同长用在ListView,GridView等控件中，实现一个ContextMenu菜单通常需要以下几步:

　　1，向某个View注册上下文菜单，通过调用 registerForContextMenu() 如， registerForContextMenu(listView);

　　2，在Activity或者在Fragment中实现 onCreateContextMenu()方法，如，

　　

public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        // TODO 自动生成的方法存根
       
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();  //Menuinflater实例允许加载上下文菜单，
        inflater.inflate(R.menu.main, menu);
    }

　　3，实现onContextItemSelected().方法，当用户选中一个菜单项时，系统会自动调用这个函数。如，

//响应上下文菜单的操作
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        switch (item.getItemId()) {
        case R.id.delete:
            Toast.makeText(MainActivity.this, "Delete", 1).show();
            break;
        case R.id.share:
            Toast.makeText(MainActivity.this, "Share", 1).show();
            break;
        case R.id.edit:
            Toast.makeText(MainActivity.this, "Edit", 1).show();
            break;
        }
        return super.onContextItemSelected(item);
    }

　　下面给出整个源代码：

　　在activity_main.xml文件中:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" >
    </ListView>

</RelativeLayout>

在main.xml文件中:

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

    <item
        android:id="@+id/edit"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="Edit"/>
    <item
        android:id="@+id/share"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="Share"/>
    <item
        android:id="@+id/delete"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="Delete"/>

</menu>

在MainActivity.java文件中:

public class MainActivity extends Activity {

    private List<Object> list;
    private ListView listView = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        list = getData();
        ArrayAdapter< Object> adapter = 
                new ArrayAdapter<Object>(MainActivity.this, android.R.layout.simple_list_item_1, list);
        
        listView = (ListView) findViewById(R.id.listView);
        listView.setAdapter(adapter);
        registerForContextMenu(listView);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    List<Object> getData(){
        List<Object> list = new ArrayList<Object>();
        for(int i = 1; i <= 7;i++){
            list.add("jack" + i);
        }
        return list;
    }
    
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        // TODO 自动生成的方法存根
        
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
    }
}

运行结果:

 

　　

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