Android_Broadcast

2023-02-26 14:27:47

/**

 * 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

 *

 */

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;

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

    }

}
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