Android基础-上下文菜单(Content_Menu)

上下文菜单，当用户长时间点击的时候，出现

第一步：注册绑定按钮 

registerForContextMenu(findViewById(R.id.ctx_btn));

第二步：设置监听器 

    findViewById(R.id.ctx_btn).setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                startActionMode(cb);
                return false;
            }
        });

第三步：对监听器设置事件

 ActionMode.Callback cb = new ActionMode.Callback() {
        //创建，在启动上下文模式操作(startActionMode(Callback))时调用
        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            Log.e("TAG", "创建");
            getMenuInflater().inflate(R.menu.context, menu);
            return true;
        }

        //在创建方法后进行调用
        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            Log.e("TAG", "准备");
            return false;
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            Log.e("TAG", "点击");
            switch (item.getItemId()) {
                case R.id.delete:
                    Toast.makeText(MainActivity.this, "删除", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.opera1:
                    Toast.makeText(MainActivity.this, "操作1", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.opera2:
                    Toast.makeText(MainActivity.this, "操作2", Toast.LENGTH_SHORT).show();
                    break;
            }
            return true;
        }

        //上下文操作模式结束时被调用
        @Override
        public void onDestroyActionMode(ActionMode mode) {
            Log.e("TAG", "结束");
        }
    };

Java完整代码

package com.example.imoocapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.ActionMode;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

        //ctx_btn: 演示ContextMenu
        //1.注册
        registerForContextMenu(findViewById(R.id.ctx_btn));
        //2.创建 覆盖 onCreateContextMenu
        //3.菜单项的操作 onContextItemSelected
        //4.为按钮设置上下文操作模式
          //1实现ActionMode CallBack
          //2在View的长按事件中去启动上下文操作模式
        findViewById(R.id.ctx_btn).setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                startActionMode(cb);
                return false;
            }
        });

    }
    /*
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.delete:
                Toast.makeText(this, "删除", Toast.LENGTH_SHORT).show();
                break;
            case R.id.opera1:
                Toast.makeText(this, "操作1", Toast.LENGTH_SHORT).show();
                break;
            case R.id.opera2:
                Toast.makeText(this, "操作2", Toast.LENGTH_SHORT).show();
                break;
        }
        return super.onContextItemSelected(item);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        getMenuInflater().inflate(R.menu.context, menu);
    }
    */
    ActionMode.Callback cb = new ActionMode.Callback() {
        //创建，在启动上下文模式操作(startActionMode(Callback))时调用
        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            Log.e("TAG", "创建");
            getMenuInflater().inflate(R.menu.context, menu);
            return true;
        }

        //在创建方法后进行调用
        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            Log.e("TAG", "准备");
            return false;
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            Log.e("TAG", "点击");
            switch (item.getItemId()) {
                case R.id.delete:
                    Toast.makeText(MainActivity.this, "删除", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.opera1:
                    Toast.makeText(MainActivity.this, "操作1", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.opera2:
                    Toast.makeText(MainActivity.this, "操作2", Toast.LENGTH_SHORT).show();
                    break;
            }
            return true;
        }

        //上下文操作模式结束时被调用
        @Override
        public void onDestroyActionMode(ActionMode mode) {
            Log.e("TAG", "结束");
        }
    };

}

content.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/delete"
        android:title="删除" />
    <item android:title="重命名" >
        <menu >
            <item
                android:id="@+id/opera1"
                android:title="操作1" />
            <item
                android:id="@+id/opera2"
                android:title="操作2" />
        </menu>
    </item>
</menu>

activity.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/ctx_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="上下文菜单"
        app:layout_constraintTop_toTopOf="parent" />




</androidx.constraintlayout.widget.ConstraintLayout>