11 ContextMenu 上下文菜单按钮

ContextMenu 上下文菜单

1. 在res下的menu里写菜单项
2. 在逻辑代码中 写OnCreateContextMenu() 方法 将菜单项添加到菜单
3. 对菜单项进行监听 onContextItemSelected()
   
   • //获取ListView 当前item的下标
   • AdapterContextMenuInfo info = (AdapterContextMenuInfo) menuInfo;
   • 4,note:registerForContextMenu(tv);进行注册上下文菜单给控件

图标不显示参考不显示菜单按钮解决方法

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• 案例1 :给普通TextView设置
• xml代码：

<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"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.fmy.context.MainActivity" >    <TextView        android:id="@+id/tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" /></RelativeLayout>

• java代码：

package com.fmy.context;import android.app.Activity;import android.graphics.Color;import android.os.Bundle;import android.view.ContextMenu;import android.view.MenuItem;import android.view.View;import android.view.ContextMenu.ContextMenuInfo;import android.widget.TextView;public class MainActivity extends Activity {    private TextView tv;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        tv = (TextView) findViewById(R.id.tv);        registerForContextMenu(tv);    }    @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {        super.onCreateContextMenu(menu, v, menuInfo);        getMenuInflater().inflate(R.menu.main, menu);    }    @Override    public boolean onContextItemSelected(MenuItem item) {        switch (item.getItemId()) {        case R.id.green:            tv.setTextColor(Color.GREEN);            break;        case R.id.red:            tv.setTextColor(Color.RED);            break;        default:            break;        }        return super.onContextItemSelected(item);    }}

• 效果：
• 长按TextView 弹出菜单
  

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• 案例二: listview和按钮
  xml代码：

<menu xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    tools:context="com.fmy.context.MainActivity" >       <item        android:id="@+id/action_delete"        android:orderInCategory="100"        android:showAsAction="never"        android:title="删除信息"/></menu>

<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"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.fmy.context.MainActivity" >    <ListView        android:id="@+id/lv"        android:layout_width="match_parent"        android:layout_height="match_parent" >    </ListView></RelativeLayout>

java代码：

package com.fmy.context;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.view.ContextMenu;import android.view.ContextMenu.ContextMenuInfo;import android.view.LayoutInflater;import android.view.MenuItem;import android.view.View;import android.widget.AdapterView.AdapterContextMenuInfo;import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.TextView;public class MainActivity extends Activity {    private TextView tv;    private ListView lv;    private int pos;    private List<String> list;    private ArrayAdapter<String> adapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        lv = (ListView) findViewById(R.id.lv);        list = new ArrayList<String>();        for (int i = 0; i < 50; i++) {            list.add("" + i);        }        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);        lv.setAdapter(adapter);        registerForContextMenu(lv);    }    @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {        // TODO Auto-generated method stub        super.onCreateContextMenu(menu, v, menuInfo);        getMenuInflater().inflate(R.menu.main, menu);        AdapterContextMenuInfo info = (AdapterContextMenuInfo) menuInfo;        pos = info.position;    }    @Override    public boolean onContextItemSelected(MenuItem item) {        list.remove(pos);        adapter.notifyDataSetChanged();        return super.onContextItemSelected(item);    }}

效果图: