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android 广播机制

2024-08-05 11:34:28   224人阅读

　　Android广播机制指的是，在一个应用程序运行的时候可以自定义一个消息类型，让相应的接收器去处理这个消息或者是系统消息，比如来电话了、来短信了、手机没电了等等系统发送的消息；

　　Android提供了两种注册广播接受者的形式，分别是在程序中动态注册和在xml中指定。他们之间的区别就是作用的范围不同，程序动态注册的接收者只在程序运行过程中有效，而在xml注册的接收者不管你的程序有没有启动都会起作用；

 

基于XML配置的注册广播形式为：

 

点击发送按钮，打印信息为：

 

代码如下：

activity_main.xml

<RelativeLayout 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"    tools:context="com.xiaozhang.broadcast1.MainActivity" >    <Button        android:id="@+id/button"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="点击发送" /></RelativeLayout>

 

MainActivity.java

package com.xiaozhang.broadcast1;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity {    private Button sendButton;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        sendButton = (Button) findViewById(R.id.button);        sendButton.setOnClickListener(new BroadcastListener());    }    class BroadcastListener implements OnClickListener {        @Override        public void onClick(View v) {            Intent intent = new Intent();            intent.setAction(Intent.ACTION_EDIT);            MainActivity.this.sendBroadcast(intent);        }    }}

 

TestReceiver.java

package com.xiaozhang.broadcast1;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;public class TestReceiver extends BroadcastReceiver {    @Override    public void onReceive(Context context, Intent intent) {        String action = intent.getAction();        System.out.println("接收到了信息:" + action);    }}

 

在AndroidManifest.xml中配置为：

在<application>中加入：

<receiver android:name=".TestReceiver" >            <intent-filter>                <action android:name="android.intent.action.EDIT" />            </intent-filter>        </receiver>

 

 

在程序中动态指定为：

直接点击发送广播，没反应，要先注册，再发送，再取消注册；

 

代码实现：

activity_main.xml

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.xiaozhang.broadcast2.MainActivity" >    <Button        android:id="@+id/button1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="注册广播" />    <Button        android:id="@+id/button2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@id/button1"        android:text="发送广播" />    <Button        android:id="@+id/button3"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@id/button2"        android:text="取消注册" /></RelativeLayout>

MainActivity.java

package com.xiaozhang.broadcast2;import java.util.Calendar;import android.app.Activity;import android.content.Intent;import android.content.IntentFilter;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity {    private Button button1;    private Button button2;    private Button button3;    private ReceiveBroadCast receiveBroadCast = null;    private static final String ACTION = "android:provider.Telephony.SMS_RECEIVE";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button1 = (Button) findViewById(R.id.button1);        button2 = (Button) findViewById(R.id.button2);        button3 = (Button) findViewById(R.id.button3);        button1.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                receiveBroadCast = new ReceiveBroadCast();                IntentFilter filter = new IntentFilter();                filter.addAction(ACTION);                registerReceiver(receiveBroadCast, filter);            }        });        button2.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                Intent intent = new Intent();                intent.putExtra("data", "message: "                        + Calendar.getInstance().get(Calendar.SECOND));                intent.setAction(ACTION);                sendBroadcast(intent);            }        });        button3.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                unregisterReceiver(receiveBroadCast);            }        });    }}

 

ReceiveBroadCast.java

package com.xiaozhang.broadcast2;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.util.Log;public class ReceiveBroadCast extends BroadcastReceiver {    private static final String TAG = "MyReceiver";    @Override    public void onReceive(Context context, Intent intent) {        String message = intent.getStringExtra("data");        Log.i(TAG, message);    }}

 

推荐阅读：

http://www.cnblogs.com/qianlifeng/archive/2011/03/06/1972305.html

http://blog.csdn.net/abc5382334/article/details/15796823

http://www.cnblogs.com/totem1990/archive/2012/09/10/2679391.html

android 广播机制


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