学习Android广播机制
在Android中实现广播,首先我们要在Manifest.xml文件中配置一个标签,这个标签必须有一个android:name属性,值为继承自BroadcastReceiver类的接收器类!这个标签还有一个子标签为,这个标签很重要,是指定接收器需要接收哪种广播。另外,还有配置一个用户权限:,具体的值可以参考官方API文档。
另外一个比较重要的步骤是必须有一个类继承自BroadcastReceiver类,并复写onReceiver方法,在该方法中处理接收到广播后需要处理的事情!
下面来看一个具体的例子,有助于更好的理解广播机制是怎么一回事。
UI部分就不说了,Activity上就加了一个按钮,点击后发送广播。接收器接收到广播后在终端输出一句话。
首先看AndroidManifest.xml文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.gufengxiachen.broadcast"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".BroadCast"
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=".MyBroadCastReceiver">
<intent-filter>
<action android:name="android.intent.action.EDIT"></action>
</intent-filter>
</receiver>
</application>
<uses-permission android:name="android.permission.RECEIVE_SMS"></uses-permission>
</manifest>
下面是Activity:
package com.gufengxiachen.broadcast;
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 BroadCast extends Activity {
/* Called when the activity is first created. /
private Button bound =null;
private Button unbound =null;
private Button sendBroadCast =null;
private SecondBroadCastReceiver sbr =null;
public static final String SMS_ACTION="android.provider.Telephony.SMS_RECEVIER";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
bound = (Button)findViewById(R.id.bound);
unbound = (Button)findViewById(R.id.unbound);
sendBroadCast = (Button)findViewById(R.id.sendBroadCast);
bound.setOnClickListener(new BoundListener());
unbound.setOnClickListener(new UnboundListener());
sendBroadCast.setOnClickListener(new SendBroadCast());
}
class SendBroadCast implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_EDIT);
BroadCast.this.sendBroadcast(intent);
}
}
class BoundListener implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
sbr = new SecondBroadCastReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(SMS_ACTION);
BroadCast.this.registerReceiver(sbr, filter);
}
}
class UnboundListener implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
BroadCast.this.unregisterReceiver(sbr);
}
}
}
最后是接收器类:
package com.gufengxiachen.broadcast;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class MyBroadCastReceiver extends BroadcastReceiver{
public MyBroadCastReceiver(){
}
@Override
public void onReceive(Context context, Intent intent) {
System.out.println("message receiver");
}
}
后文
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第三章 Android 技术栈从入门到熟悉
● 开始
● Activity
● Service 服务
● Broadcast 广播机制
● Fragment
● res应用资源
● 权限
● TextView 显示文字
● EditText 用户输入
● Button 按钮
● ImageView 图片显示
● Layout布局
● DrawerLayout侧滑栏
● RecyclerView 显示列表
● 多线程
● IO 操作
● 存储
● NetWork 网络
● ProgressBar进度条
● View
● 自定义View
● 动画
● WebView
● StatusBar
● Camera相机
● Media
● Bluetooth 蓝牙
● WiFi连接
● 获取手机当前角度
● launcher
● AIDL
● zip
● Binder
● Notification 通知
● PackageManager
● RTFSC
● 设计模式
● 第三方库
● Android Studio
● 模块化
● Gradle
● NDK
● 调试
Android Jetpack 全家桶全面学习
● 介绍
● databinding
● LiveData 事件传送
● LifeCycle 生命周期
● WorkManager
● ViewModel
● 数据库
● Paging