android开发-广播的基本用法

最新推荐文章于 2023-03-27 10:21:23 发布

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本文详细介绍了Android开发中广播的基本概念、使用方法，并通过实例演示了如何在XML布局文件和代码中注册广播接收器。重点区分了XML注册与代码注册的区别，以及在程序关闭后接收器是否继续运行的问题。

android开发-广播的基本用法

注册receiver有两种方法，视频里说的。一种是用xml注册，一种是直接在代码里面注册。

一，用xml注册receiver。

注意：用xml注册的receiver并不随程序关闭而关闭。你关闭了程序，但是receiver并没有关闭，要注意。

布局：一个按钮

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <Button
        android:id="@+id/button1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="xml注册--发送广播" />
</LinearLayout>

写一个receiver类

package com.example.broadcasttest;
 
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
 
public class MyReceiver extends BroadcastReceiver {
   
    //每接收到一次广播都生成一个对象，调用onReceive之后对象销毁
    //下次再接收到广播再生成一个对象。
    public MyReceiver() {
        System.out.println("构造方法");
    }
 
    @Override
    public void onReceive(Context arg0, Intent arg1) {
        // TODO Auto-generated method stub
        System.out.println("onReceive   接收到了广播");
    }
}

注册receiver，写完了receiver类记住注册。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.broadcasttest"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
 
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.broadcasttest.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>
       
       
        <!-- 用这种方法注册的receiver，当程序关闭之后receiver并不会关闭 -->
        <receiver android:name=".MyReceiver">
            <intent-filter >
                <action android:name="android.intent.action.EDIT"/>
            </intent-filter>
        </receiver>
       
       
    </application>
 
</manifest>

Activity类，用来发广播，测试上面写的接收器有没有接收到。

package com.example.broadcasttest;
 
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
 
public class MainActivity extends Activity {
    private Button button;
   
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        button = (Button) this.findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent();
                intent.setAction(Intent.ACTION_EDIT);
                MainActivity.this.sendBroadcast(intent);
            }
        });
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
 
}

二，用代码注册receiver。

和上面一样，写一个接收器

package com.example.broadcasttest2;
 
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
 
public class myReceiver extends BroadcastReceiver {
 
    @Override
    public void onReceive(Context arg0, Intent arg1) {
        // TODO Auto-generated method stub
        System.out.println("接收到信息了。");
    }
 
}

布局：
Main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
 
    <Button
        android:id="@+id/button1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="注册receiver" />
 
    <Button
        android:id="@+id/button2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="解除receiver" />
 
    <Button
        android:id="@+id/button3"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Button" />
 
</LinearLayout>

测试类
MainActivity

package com.example.broadcasttest2;
 
import android.app.Activity;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
 
public class MainActivity extends Activity {
    private Button registeReceiver;
    private Button unRegistereceiver;
    private Button sendBroadcast;
    private myReceiver myReceiver;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        //绑定receiver
        registeReceiver = (Button) this.findViewById(R.id.button1);
        registeReceiver.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                myReceiver = new myReceiver();
                IntentFilter filter = new IntentFilter();
                //接收信息的action
                filter.addAction(Intent.ACTION_EDIT);
                MainActivity.this.registerReceiver(myReceiver, filter);
                System.out.println("绑定receiver");
            }
        });
       
        //解除rece
        unRegistereceiver = (Button) this.findViewById(R.id.button2);
        unRegistereceiver.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                MainActivity.this.unregisterReceiver(myReceiver);
                System.out.println("解除receiver");
            }
        });
       
        //发送广播
        sendBroadcast = (Button) this.findViewById(R.id.button3);
        sendBroadcast.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setAction(Intent.ACTION_EDIT);
                MainActivity.this.sendBroadcast(intent);
            }
        });
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
 
}