上下文菜单

通过上下文菜单修改桌面背景色,java代码如下

public class MainActivity1 extends Activity {

    private static final int GREEN = 1;
    private static final int BLUE = 2;
    private static final int RED = 3;
    private LinearLayout ll;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test3);

        ll = (LinearLayout) findViewById(R.id.ll);
        registerForContextMenu(ll);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        menu.add(1, GREEN, 1, "绿色");
        menu.add(1, BLUE, 1, "蓝色");
        menu.add(1, RED, 1, "红色");
        
        
        menu.setGroupCheckable(1, true, true);;
        menu.setHeaderTitle("请选择背景色");
        
        
        super.onCreateContextMenu(menu, v, menuInfo);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case GREEN:
            item.setChecked(true);
            ll.setBackgroundColor(Color.GREEN);
            break;
        case BLUE:
            item.setChecked(true);
            ll.setBackgroundColor(Color.BLUE);
            break;
        case RED:
            item.setChecked(true);
            ll.setBackgroundColor(Color.RED);
            break;

        default:
            break;
        }
        return super.onContextItemSelected(item);
    }
}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:id="@+id/ll"
    android:orientation="vertical" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="点击上下文菜单修改桌面背景" />

</LinearLayout>