1.广播接收者
广播接收者简单地说就是接收广播意图的Java类,此Java类继承BroadcastReceiver类,重写:
public void onReceive(Context context,Intent intent),其中intent可以获得传递的数据;
广播意图就是通过Context.sendBroadcast(Intent intent)或Context.sendOrderedBroadcast(Intent intent)发送的意图,通过这个语句,能够广播给所有满足条件的组件,比如intent设置了action="com.xiazdong",则所有在AndroidManifest.xml中设置过<action android:name="com.xiazdong"/>的广播接收者都能够接收到广播;
注:onReceive方法必须在10秒内完成,如果没有完成,则抛“Application No Response”当广播接收者onReceive方法需要执行很长时间时,最好将此耗时工作通过Intent发送给Service,由Service完成,并且不能使用子线程解决,因为BroadcastReceiver是接收到广播后才创建的,并且生命周期很短,因此子线程可能在没有执行完就已经被杀死了。
- public void onReceive(Context context,Intent intent){
- Intent intent = new Intent(context,XxxService.class);
- context.startService(intent);
- }
2.广播发送者
通常广播发送方就是调用Context.sendBroadcast()的程序,而广播接收者就是继承BroadcastReceiver的程序;
通常广播发送方都是通过隐式意图,这样才能发送给多人;
广播发送方分为普通广播和有序广播;
同步广播:发送方发出后,几乎同时到达多个广播接收者处,某个接收者不能接收到广播后进行一番处理后传给下一个接收者,并且无法终止广播继续传播;Context.sendBroadcast(intent);
有序广播:广播接收者需要提前设置优先级,优先级高的先接收到广播,优先级数值为-1000~1000,在AndroidManifest.xml的<intent-filter android:priority="xxx">设置;比如存在3个广播接收者A、B、C,优先级A>B>C,因此A最先收到广播,当A收到广播后,可以向广播中添加一些数据给下一个接收者(intent.putExtra()),或者终止广播(abortBroadcast());Context.sendOrderedBroadcast(intent);
二、广播接收者核心代码
同步广播发送方核心代码:
- Intent intent = new Intent();
- intent.setAction("...");
- Context.sendBroadcast(intent);
有序广播发送方核心代码:
- Intent intent = new Intent();
- intent.setAction("...");
- Context.sendOrderedBroadcast(intent,null);
广播接收者核心代码:
- public class Receiver extends BroadcastReceiver{
- public void onReceive(Context context, Intent intent) {
- Bundle bundle = intent.getExtras();
- ...
- }
- }
AndroidManifest.xml
- <application>
- <receiver android:name=".Receiver">
- <intent-filter android:priority="1000"> <!-- 设置最高优先级 -->
- <action android:name="com.xiazdong"/>
- </intent-filter>
- </receiver>
- </application>
三、广播实例
(1)广播发送者:
- package com.xiazdong.broadcastsender;
- 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;
- import android.widget.Toast;
- public class MainActivity extends Activity {
- private Button button;
- private OnClickListener listener = new OnClickListener(){
- @Override
- public void onClick(View v) {
- Intent intent = new Intent();
- intent.setAction("com.xiazdong");
- intent.putExtra("name", "xiazdong");
- MainActivity.this.sendBroadcast(intent);
- Toast.makeText(getApplicationContext(), "发送广播成功", Toast.LENGTH_SHORT).show();
- }
- };
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- button = (Button)this.findViewById(R.id.button);
- button.setOnClickListener(listener);
- }
- }
(2)广播接收者
- package com.xiazdong.broadcastreceiver1;
- import android.content.BroadcastReceiver;
- import android.content.Context;
- import android.content.Intent;
- import android.util.Log;
- public class Receiver extends BroadcastReceiver {
- @Override
- public void onReceive(Context context, Intent intent) {
- String name = intent.getExtras().getString("name");
- Log.i("Recevier1", "接收到:"+name);
- }
- }
AndroidManifest.xml
- <receiver android:name=".Receiver">
- <intent-filter>
- <action android:name="com.xiazdong"/>
- </intent-filter>
- </receiver>
结果:
2.有序广播实例
场景说明:
(1)广播发送者
- package com.xiazdong.broadcastsender;
- 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;
- import android.widget.Toast;
- public class MainActivity extends Activity {
- private Button button;
- private OnClickListener listener = new OnClickListener(){
- @Override
- public void onClick(View v) {
- Intent intent = new Intent();
- intent.setAction("com.xiazdong");
- intent.putExtra("name", "xiazdong");
- MainActivity.this.sendOrderedBroadcast(intent, null); //有序广播发送
- Toast.makeText(getApplicationContext(), "发送广播成功", Toast.LENGTH_SHORT).show();
- }
- };
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- button = (Button)this.findViewById(R.id.button);
- button.setOnClickListener(listener);
- }
- }
(2)广播接收者
Receiver1
- package com.xiazdong.broadcastreceiver1;
- import android.content.BroadcastReceiver;
- import android.content.Context;
- import android.content.Intent;
- import android.util.Log;
- public class Receiver extends BroadcastReceiver {
- @Override
- public void onReceive(Context context, Intent intent) {
- String name = intent.getExtras().getString("name");
- Log.i("Recevier1", "接收到:"+name);
- abortBroadcast(); //Receiver1接收到广播后中断广播
- }
- }
广播发送者 intent = new Intent(AppConstants.REFRESH_ACTION); intent.putExtra(AppConstants.ORDER_ID, orderId); intent.putExtra(AppConstants.KEY_TYPE, AppConstants.KEY_REFRESH_TRADESTATUS); LocalBroadcastManager.getInstance(ReceivablesModeActivity.this).sendBroadcast(intent); 广播接受者 LocalBroadcastManager.getInstance(ReceivablesModeActivity.this).registerReceiver(receiverRefresh, filterRefresh); public IntentFilter filterRefresh = new IntentFilter( AppConstants.REFRESH_ACTION); public RefreshActivityReceiver receiverRefresh = new RefreshActivityReceiver(); class RefreshActivityReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String type = intent.getStringExtra(AppConstants.KEY_TYPE); if (!TextUtils.isEmpty(type) && type.equals(AppConstants.KEY_REFRESH_TRADESTATUS)) { dismissProgressDialog(); toast("交易成功"); intent = new Intent(ReceivablesModeActivity.this, TradingSuccessActivity.class); intent.putExtra(AppConstants.ORDER_ID, orderId); startActivity(intent); finish(); overridePendingTransition(0, R.anim.out_down); } } }