Android UI教程 - Android上下文菜单

Android UI教程 - Android上下文菜单

上下文菜单与活动的视图相关联，并且当用户轻击并保持项目时显示。

要将上下文菜单与视图相关联，使用该特定视图的setOnCreateContextMenuListener()方法。

下面尝试一下显示如何将上下文菜单与Button视图相关联。

例子

将以下语句添加到main.xml文件中:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Click and hold on it" />

</LinearLayout>

将以下语句添加到MenusActivity.java文件:

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
//from  w  w w.j av  a 2s. co m
public class MenusActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button btn = (Button) findViewById(R.id.button1);
        btn.setOnCreateContextMenuListener(this);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View view,
    ContextMenuInfo menuInfo)
    {
         super.onCreateContextMenu(menu, view, menuInfo);
         CreateMenu(menu);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        CreateMenu(menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
         return MenuChoice(item);
    }
    private void CreateMenu(Menu menu)
    {
        MenuItem mnu1 = menu.add(0, 0, 0, "Item 1");
        {
            mnu1.setAlphabeticShortcut( "a");
            mnu1.setIcon(R.drawable.ic_launcher);
        }
        MenuItem mnu2 = menu.add(0, 1, 1, "Item 2");
        {
            mnu2.setAlphabeticShortcut( "b");
            mnu2.setIcon(R.drawable.ic_launcher);
        }
        MenuItem mnu3 = menu.add(0, 2, 2, "Item 3");
        {
            mnu3.setAlphabeticShortcut( "c");
            mnu3.setIcon(R.drawable.ic_launcher);
        }
        MenuItem mnu4 = menu.add(0, 3, 3, "Item 4");
        {
            mnu4.setAlphabeticShortcut( "d");
        }
        menu.add(0, 4, 4, "Item 5");
        menu.add(0, 5, 5, "Item 6");
        menu.add(0, 6, 6, "Item 7");
    }

    private boolean MenuChoice(MenuItem item)
    {
        switch (item.getItemId()) {
        case 0:
            Toast.makeText (this, "You clicked on Item 1",
                Toast.LENGTH_LONG).show();
            return true;
        case 1:
            Toast.makeText (this, "You clicked on Item 2",
                Toast.LENGTH_LONG).show();
            return true;
        case 2:
            Toast.makeText (this, "You clicked on Item 3",
                Toast.LENGTH_LONG).show();
            return true;
        case 3:
          Toast.makeText (this, "You clicked on Item 4",
              Toast.LENGTH_LONG).show();
          return true;
      case 4:
          Toast.makeText (this, "You clicked on Item 5",
              Toast.LENGTH_LONG).show();
          return true;
      case 5:
          Toast.makeText (this, "You clicked on Item 6",
              Toast.LENGTH_LONG).show();
          return true;
      case 6:
          Toast.makeText (this, "You clicked on Item 7",
              Toast.LENGTH_LONG).show();
          return true;
      }
      return false;
  }

}