Android study notes-the use of ContextMenu

http://blog.csdn.net/wannerwang/article/details/50532271

Use of ContextMenu

ContextView , related to the context, the idea is similar to the shortcut menu that pops up when you right-click and click to build in Windows  . The operation is to hold down a component for a long time.

The effect is as follows:

 

Long press as follows:

 

The creation steps are as follows:

1 Override Activity 's  onCreateContextMenu  () method and call Menu  's add  () method to add menu items

2 : Override Activity 's onContextItemSelected (MenuItem item)  to respond to the event.

3 : Call the registForContextMenu  () method to register the context menu for the view.

Note: Only one ContenxtMenu can be used in one interface .

ContextMenu also has two registration methods.

The implementation process of Xml  registration is as follows:

In the res / menu  to create a folder  context_menu.xml file

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".MainActivity">
    <item
        android:id="@+id/red"
        android:orderInCategory="100"
        android:title="红色" />
    <item
        android:id="@+id/green"
        android:orderInCategory="200"
        android:title="绿色" />
    <item
        android:id="@+id/blue"
        android:orderInCategory="300"</menu>" />blue
        android:title="

在MianActivity文件中加载布局文件。

package com.xiyou.com.meanususe;

import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

//上下文菜单
public class ContextMenuus extends AppCompatActivity {
    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.context_menu);
               // 注册上下文菜单到TextView组件上
        registerForContextMenu(tv);
    }

    // 创建上下文菜单的事件方法
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        getMenuInflater().inflate(R.menu.context_menu, menu);
        super.onCreateContextMenu(menu, v, menuInfo);
    }

    // 上下文菜单的单击事件
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.red:
                tv.setBackgroundColor(Color.RED);
                break;
            case R.id.green:
                tv.setBackgroundColor(Color.GREEN);
                break;
            case R.id.blue:
                tv.setBackgroundColor(Color.BLUE);
                break;
        }
        return super.onContextItemSelected(item);
    }
}