Android_Broadcast

Posted 2020-07-23 Tears_fg

Manifest.xml

 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.android_broadcast"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="15" />
    <uses-permission android:name="android.permission.BROADCAST_STICKY"/>
  

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name="com.example.android_broadcast.MyBroadcastReceiver1">
            <intent-filter android:priority="200">
                <action android:name="broadcast_one"/>
            </intent-filter>
        </receiver>
         <receiver android:name="com.example.android_broadcast.MyBroadcastReceiver2">
            <intent-filter android:priority="100">
                <action android:name="broadcast_one"/>
            </intent-filter>
        </receiver>
    </application>

</manifest>

 

xml文件

<LinearLayout 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:orientation="vertical"
    tools:context="com.example.android_broadcast.MainActivity" >
    <Button 
        android:id="@+id/btn_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="doClick"
        android:text="发送一条普通广播"/>
    <Button 
        android:id="@+id/btn_2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="doClick"
        android:text="发送一条有序广播"/>
    <Button 
        android:id="@+id/btn_3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="doClick"
        android:text="发送一条异步广播"/>
    

</LinearLayout>

源代码MainActivity：

package com.example.android_broadcast;

import android.app.Activity;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
/**
 * Broadcast(广播)：是一种广泛运用的在应用程序之间传输信息的机制
 * 
 * BroadcastReceiver(广播接收者)
 *     是对发送出来的广播进行过滤接收并响应的一类组件，它就是用来接收来自系统和应用中的广播
 * 使用方法：
 *         发送：把信息装入一个intent对象（action,category）
 *         通过调用相应方法将intent对象以广播形式发送出去
 *         sendBroadcast（）
 *         sendOrdercast()
 *         sendStickyBroadcast()
 *    注意！！！
 *        BroadcastReceiver生命周期只有十秒左右，
 *        如果在onReceiver内做超过十秒内的事情，就会报错
 *        应该通过发送Intent给service，由service来完成
 *        不能用子线程
 *        
 *广播的种类：
 *    普通广播，有序广播，异步广播（不能讲处理结果传给下一个接收者，无法终止广播）
 * 普通广播的特点：
 *     -同级别接收先后是随机的（无序）
 *     -级别低的后收到广播（priority）
 *     -接收器不能截断广播的传播也不能处理广播,否则报错
 *     -同级别动态注册高于静态注册
 *     
 * 有序广播的特点：
 *     -同级别接收顺序是随机的
 *     -能截断广播的继续传播，高级别的广播接收器收到该广播后，可以决定把该广播是否截断
 *     -接收器能截断广播的继续传播，也能处理广播
 *     -同级别动态注册高于静态注册
 * 
 *静态注册：在manifest里面注册(与activity类似)
 * <receiver android:name="com.examle.android_broadcast.MyBroadcastReceiver1">
            <intent-filter android:priority="200" >
                <action android:name="broadcast_one"/>
            </intent-filter>
   </receiver>
    android:priority="200" 优先级，范围-1000到1000
   动态注册：在MainActivity中注册，
           IntentFilter filter = new IntentFilter("broadcast_one");//创建过滤器，过滤动作为broadcast_one的广播
        MyBroadcastReceiver1 receiver = new MyBroadcastReceiver1();//创建广播接收对象
        registerReceiver(receiver, filter);//注册广播
！！！注意：动态注册广播后需要在广播接收后关闭广播(重写onDestory方法)
   
   
 * @author Administrator
 *
 */

public class MainActivity extends Activity {

    private MyBroadcastReceiver3 receiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        /*IntentFilter filter = new IntentFilter("broadcast_one");//创建过滤器，过滤动作为broadcast_one的广播
        MyBroadcastReceiver1 receiver = new MyBroadcastReceiver1();//创建广播接收对象
        registerReceiver(receiver, filter);//注册广播
*/    
    
    }
    public void doClick(View view){
        switch(view.getId()){
        case R.id.btn_1://发送一条普通广播
            Intent intent = new Intent();
            intent.putExtra("msg", "这是一条普通广播");//设置发送的信息
            intent.setAction("broadcast_one");//设置发送的动作
            sendBroadcast(intent);//发送广播
            
            break;
        case R.id.btn_2://发送一条有序广播
            Intent intent2 = new Intent();
            intent2.putExtra("msg", "这是一条有序广播");
            intent2.setAction("broadcast_one");//跳转的动作
            sendOrderedBroadcast(intent2, null);
            break;
        case R.id.btn_3://发送一条异步广播，
            //异步广播不能终止也就是会每次都存在，用先发送后注册来说明,点击n次出现n条广播 unregisterReceiver(receiver);该方法对其并不起作用
            Intent intent3 = new Intent();
            intent3.putExtra("msg", "这是一条异步广播");
            intent3.setAction("broadcast_three");
            sendStickyBroadcast(intent3);
            IntentFilter filter = new IntentFilter("broadcast_three");
            receiver = new MyBroadcastReceiver3();
            registerReceiver(receiver, filter);
            
            break;
            
            
        }
    }
    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        //unregisterReceiver(receiver);
    }
}

MyBroadcastReceiver1：

package com.example.android_broadcast;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;

public class MyBroadcastReceiver1 extends BroadcastReceiver{

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String s = intent.getStringExtra("msg");
        System.out.println("broadcast_one接收消息："+s);
        //有序广播中，可以对收到的数据进行截断或处理
        //abortBroadcast();//截断广播，如果是普通广播，就会失败
        Bundle bundle = new Bundle();
        bundle.putString("newMsg", "数据被广播1处理过-->"+s);
        setResultExtras(bundle);
    }
    

}

MyBroadcastReceiver2：

package com.example.android_broadcast;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;

public class MyBroadcastReceiver2 extends BroadcastReceiver{

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String s = intent.getStringExtra("msg");
        System.out.println("broadcast_two接收消息："+s);
        Bundle bundle = getResultExtras(true);
        String s2 = bundle.getString("newMsg");
        System.out.println("broadcastreceiver2得到的结果是："+s2);
    }

}

 

MyBroadcastReceiver3：

package com.example.android_broadcast;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class MyBroadcastReceiver3 extends BroadcastReceiver{

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String s = intent.getStringExtra("msg");
        System.out.println("broadcast_three接收消息："+s);
        //abortBroadcast();//截断广播，因为是普通广播，所以会失败
    
    }

}