安卓控件——定时广播案例

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安卓控件——广播

其实在我们的安卓系统中有好多的地方都应用到了广播的部分：比如当我们手机电量很低的时候，手机就会发一个广播，告知用户，作出相应的操作。

1.项目布局：

7个button，俩text；

2.布局文件：

activity_main:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:outlineAmbientShadowColor="@android:color/holo_blue_bright">

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/button2"
        android:layout_alignLeft="@+id/button2"
        android:text="Handler方式定时发送广播" />

    <Button
        android:id="@+id/button5"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="176dp"
        android:text="取消发送广播" />

    <Button
        android:id="@+id/button7"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button5"
        android:layout_alignLeft="@+id/button5"
        android:layout_marginBottom="46dp"
        android:text="AlarmManager方式定时发送广播  5秒后发送广播，只发送一次" />

    <Button
        android:id="@+id/button3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button5"
        android:layout_below="@+id/button5"
        android:text="Handler方式定时服务" />

    <Button
        android:id="@+id/button4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button3"
        android:layout_below="@+id/button3"
        android:text="AlarmManager方式定时服务" />

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/button7"
        android:layout_alignLeft="@+id/button7"
        android:text="AlarmManager方式定时发送广播  每隔5秒重复发广播" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button1"
        android:layout_alignParentTop="true"
        android:layout_marginTop="41dp"
        android:text="敌军还有5秒到达战场，碾碎他们" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_alignParentTop="true"
        android:text="敌军还有5秒到达战场，碾碎他们" />

    <Button
        android:id="@+id/button6"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button4"
        android:layout_below="@+id/button4"
        android:text="取消定时服务" />



</RelativeLayout>

3.服务类：

TimerService.java：

package com.example.broadcast;

import android.annotation.SuppressLint;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

public class TimerService extends Service 
    private String TAG =TimerService.class.getSimpleName();
    String message;
    int count=1;
    public TimerService() 
    
    @Override
//    创建后台进程
    public void onCreate()
        super.onCreate();
//        super.onDestroy();
//        调用发送函数
         sentMassage();
    
//    销毁后台进程
public void onDestroy()
        super.onDestroy();
        count=1;
    Log.i(TAG,"进程销毁咯！！");

//发送创建后机制的发送消息函数
    @SuppressLint("WrongConstant")
    private void sentMassage() 
        Toast.makeText(getApplicationContext(),"创建一个后台任务",0).show();
        stopSelf();
    
//    接收消息
    public String getMessage()
        return message;
    


    @Override
    public IBinder onBind(Intent intent) 
        // TODO: Return the communication channel to the service.
//        throw new UnsupportedOperationException("Not yet implemented");
        return null;

4.服务工具类：

4.1 ServiceUtil.java：

package com.example.broadcast;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

import java.util.List;

public class ServiceUtil 
    private final static String ServiceName="com.example.broadcast.TimerService";
    @SuppressLint("LongLogTag")
    public static boolean isServiceRunning(Context context, String className)
        boolean isRunning=false;
        ActivityManager activityManager =(ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningServiceInfo>serviceInfos=activityManager.getRunningServices(50);
        if (null==serviceInfos||serviceInfos.size()<1)
            return false;

        
        for (int i=0;i<serviceInfos.size();i++)
            if (serviceInfos.get(i).service.getClassName().contains(className))
                isRunning=true;
                break;
            
        
        Log.i("ServiceUtil-AlarmManager", className + " isRunning =  " + isRunning);
        return isRunning;
;
    @SuppressLint("LongLogTag")
    public static void startAMService(Context context)
        Log.i("ServiceUtil-AlarmManager", "invokeTimerPOIService wac called.." );
        PendingIntent alarmSender =null;
        Intent startIntent=new Intent(context,TimerService.class);
        startIntent.setAction(ServiceName);
        try
            alarmSender=PendingIntent.getService(context,0,startIntent,0);

        catch (Exception e)
//            异常捕获
//            闹钟异常启动
            Log.i("ServiceUtil-AlarmManager", "failed to start " + e.toString());
        
        @SuppressLint("ServiceCast") AlarmManager am =(AlarmManager) context.getSystemService(Activity.ACTIVITY_SERVICE);
        am.setInexactRepeating(AlarmManager.RTC_WAKEUP,System.currentTimeMillis(),5*1000,alarmSender);

    
    @SuppressLint("LongLogTag")
    public static void  cancleAMServicer(Context context)
//        关闭闹钟服务
        Log.i("ServiceUtil-AlarmManager", "cancleAlarmManager to start ");
        Intent intent =new Intent(context,TimerService.class);
        intent.setAction(ServiceName);
        PendingIntent pendingIntent=PendingIntent.getService(context,0,intent,PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarm=(AlarmManager)context.getSystemService(Activity.ALARM_SERVICE);
alarm.cancel(pendingIntent);
    
//    服务启动
    public static void startHandlerService(Context cxt)
        Intent intent=new Intent(cxt,TimerService.class);
        cxt.startService(intent);

    
//    服务关闭
//    服务启动
public static void stopHandlerService(Context cxt)
    Intent intent=new Intent(cxt,TimerService.class);
    cxt.stopService(intent);

4.2 实现广播和接收机制的五个步骤：

  1. 创建Intent对象，设置其属性action，这个属性是接收广播数据的标志标识，只有注册了相同的action属性的广播接收器才可以接收到相同的数据。
  2. 编写广播信息内容，将需要播发的内容封装到Intent里面，通过Activity或者是Service继承父类的Context的setContext()方式将广播发送出去；
  3. 编写继承BroadcastRecevier的子类作为广播接收器，该对象是接收广播信息并对信息进行处理的组件，在子类中重写Onrecieve()方法。
  4. 配置文件中注册广播接收类
  5. 销毁广播接收器：Android系统在执行onReceive()方法的时候会启动一个程序计时器，到一定的时间，该进程就会被销毁（所以广播机制不适合传递大数据量的信息）

5.主类：

5.1 MainActivity.java:

package com.example.broadcast;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity 

    // private TimerService mTimerService;
    private final String MESSAGE = "message";
    private Context mContext;
    private TextView tv, tv2;
    private Button bt1, bt2, bt3, bt4, bt5, bt6,bt7;
    private final int Time = 5 * 1000;
    private boolean isHanderType = false;
    private static final String ACTION_NAME = "android.intent.action.alarm.timer";
    private static final String ACTION_NAME2 = "android.intent.action.handler.timer";
    private int countHandler = 1;// handler广播发送次数计数器
    private int countAlarm = 0;// alarm广播发送次数计数器
    Handler handler = new Handler();
    Runnable runnable = new Runnable() 
        @Override
//    设置广播发送
        public void run() 
            // TODO Auto-generated method stub
//设置发布延时
            handler.postDelayed(runnable, Time);

            Intent mIntent = new Intent(ACTION_NAME2);

            mIntent.putExtra(MESSAGE, "这是第" + countHandler + "次"
                    + "Handler发送的广播,  接下来是第" + countHandler + "次");

            sendBroadcast(mIntent);

        
    ;

    Runnable runnable2 = new Runnable() 
        @Override
        public void run() 
            // TODO Auto-generated method stub
            Intent intent = new Intent(mContext, TimerService.class);
            startService(intent);
            handler.postDelayed(runnable2, Time);

        
    ;

    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() 
        @Override
        public void onReceive(Context context, Intent intent) 
            String action = intent.getAction();
            String message = intent.getStringExtra(MESSAGE);

            if (action.equals(ACTION_NAME)) 

                tv.setText("第" + countAlarm + "发送"
     
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