android特殊广播接收者

来源：互联网发布：notepad js格式化插件编辑：程序博客网时间：2024/06/06 01:11

一、概述

比如操作特别频繁的广播事件，如屏幕的锁屏和解锁、电池电量的变化等，这样的广播接收者在清单文件里面注册无效。这是因为若如此频繁的事件不停的触发应用响应，那系统的内存更不不够用，系统不得卡死啊！

若在清单文件中配置运行会有如下错误提示：

Activity com.zgs.screen.MainActivity has leaked IntentReceiver com.zgs.screen.ScreenReceiver@b6486088 that was originally registered here. Are you missing a call to unregisterReceiver()?

二、项目目录结构

二、MainActivity.java代码

package com.zgs.screen;import android.app.Activity;import android.content.IntentFilter;import android.os.Bundle;public class MainActivity extends Activity {private ScreenReceiver screenReceiver;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/* <receiver android:name="com.itheima.screen.ScreenReceiver">        <intent-filter >            <action android:name="android.intent.action.SCREEN_OFF"/>            <action android:name="android.intent.action.SCREEN_ON"/>        </intent-filter>    </receiver>*/    //[1]动态的去注册屏幕解锁和锁屏的广播screenReceiver = new ScreenReceiver();//[2]创建intent-filter对象IntentFilter filter = new IntentFilter();//[3]添加要注册的actionfilter.addAction("android.intent.action.SCREEN_OFF");filter.addAction("android.intent.action.SCREEN_ON");//[4]注册广播接收者this.registerReceiver(screenReceiver, filter);}@Overrideprotected void onDestroy() {//当activity销毁的时候  取消注册广播接收者unregisterReceiver(screenReceiver);super.onDestroy();}}

三、ScreenReceiver.java代码

package com.zgs.screen;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;public class ScreenReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {//[1]获取到当前广播的事件类型String action = intent.getAction();//[2]对当前广播事件类型做一个判断if ("android.intent.action.SCREEN_OFF".equals(action)) {System.out.println("屏幕锁屏了");}else if ("android.intent.action.SCREEN_ON".equals(action)) {System.out.println("说明屏幕解锁了~~~");}}}

四、操作演示

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