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
  

---

• 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: