編輯:Android開發實例
前面分別討論了Activity和Service,這次就輪到BroastcastReceiver,Broastcast是應用程序間通信的手段。BroastcastReceiver也是跟Intent緊密相連的,動態/靜態注冊了BroastcastReceiver之後,使用sendBroadcast把Intent發送之後,系統會自動把符合條件的BroastcastReceiver啟動,跟嵌入式系統的中斷類似。
本文主要演示了如何靜態/動態注冊BroastcastReceiver,向系統索取電量信息,以及枚舉信息的字段。本文運行截圖如下:
上圖是發送Intent至內部靜態注冊的BroadcastReceiver,接收到之後顯示消息名稱。靜態注冊比動態注冊麻煩點,先新建一個類繼承BroadcastReceiver,然後到AndroidManifest.xml 添加
- <receiver android:name="clsReceiver2">
- <intent-filter>
- <action
- android:name="com.testBroadcastReceiver.Internal_2"/>
- </intent-filter>
- </receiver>
第一個name是類名,第二個是action的名稱。
上圖是枚舉Intent消息的字段,這個功能比較適合懶人,把收到的Intent消息的字段全部分解了,再看看哪個需要的,懶得記住。實現這部分的代碼如下:
main.xml的代碼如下:
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical" android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- <Button android:id="@+id/Button01" android:layout_width="wrap_content"
- android:layout_height="wrap_content" android:text="發送至內部動態注冊的BroadcastReceiver"></Button>
- <Button android:id="@+id/Button02" android:layout_width="wrap_content"
- android:layout_height="wrap_content" android:text="發送至內部靜態注冊BroadcastReceiver"></Button>
- <Button android:id="@+id/Button03" android:layout_width="wrap_content"
- android:layout_height="wrap_content" android:text="發送至系統BroadcastReceiver"></Button>
- </LinearLayout>
testBroadcastReceiver.java的代碼如下:
- package com.testBroadcastReceiver;
- import android.app.Activity;
- import android.content.BroadcastReceiver;
- import android.content.Context;
- import android.content.Intent;
- import android.content.IntentFilter;
- import android.os.Bundle;
- import android.util.Log;
- import android.view.View;
- import android.widget.Button;
- import android.widget.Toast;
- public class testBroadcastReceiver extends Activity {
- Button btnInternal1,btnInternal2,btnSystem;
- static final String INTENAL_ACTION_1 = "com.testBroadcastReceiver.Internal_1";
- static final String INTENAL_ACTION_2 = "com.testBroadcastReceiver.Internal_2";
- static final String INTENAL_ACTION_3 = "com.testBroadcastReceiver.Internal_3";
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- btnInternal1=(Button)this.findViewById(R.id.Button01);
- btnInternal1.setOnClickListener(new ClickEvent());
- btnInternal2=(Button)this.findViewById(R.id.Button02);
- btnInternal2.setOnClickListener(new ClickEvent());
- btnSystem=(Button)this.findViewById(R.id.Button03);
- btnSystem.setOnClickListener(new ClickEvent());
- //動態注冊廣播消息
- registerReceiver(bcrIntenal1, new IntentFilter(INTENAL_ACTION_1));
- }
- class ClickEvent implements View.OnClickListener{
- @Override
- public void onClick(View v) {
- if(v==btnInternal1)//給動態注冊的BroadcastReceiver發送數據
- {
- Intent intent = new Intent(INTENAL_ACTION_1);
- sendBroadcast(intent);
- }
- else if(v==btnInternal2)//給靜態注冊的BroadcastReceiver發送數據
- {
- Intent intent = new Intent(INTENAL_ACTION_2);
- sendBroadcast(intent);
- }
- else if(v==btnSystem)//動態注冊 接收2組信息的BroadcastReceiver
- {
- IntentFilter filter = new IntentFilter();//
- filter.addAction(Intent.ACTION_BATTERY_CHANGED);//系統電量檢測信息
- filter.addAction(INTENAL_ACTION_3);//第三組自定義消息
- registerReceiver(batInfoReceiver, filter);
- Intent intent = new Intent(INTENAL_ACTION_3);
- intent.putExtra("Name", "hellogv");
- intent.putExtra("Blog", "http://blog.csdn.net/hellogv");
- sendBroadcast(intent);//傳遞過去
- }
- }
- }
- /*
- * 接收動態注冊廣播的BroadcastReceiver
- */
- private BroadcastReceiver bcrIntenal1 = new BroadcastReceiver() {
- public void onReceive(Context context, Intent intent) {
- String action = intent.getAction();
- Toast.makeText(context, "動態:"+action, 1000).show();
- }
- };
- private BroadcastReceiver batInfoReceiver = new BroadcastReceiver() {
- public void onReceive(Context context, Intent intent) {
- String action = intent.getAction();
- //如果捕捉到的action是ACTION_BATTERY_CHANGED
- if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {
- //當未知Intent包含的內容,則需要通過以下方法來列舉
- Bundle b=intent.getExtras();
- Object[] lstName=b.keySet().toArray();
- for(int i=0;i<lstName.length;i++)
- {
- String keyName=lstName[i].toString();
- Log.e(keyName,String.valueOf(b.get(keyName)));
- }
- }
- //如果捕捉到的action是INTENAL_ACTION_3
- if (INTENAL_ACTION_3.equals(action)) {
- //當未知Intent包含的內容,則需要通過以下方法來列舉
- Bundle b=intent.getExtras();
- Object[] lstName=b.keySet().toArray();
- for(int i=0;i<lstName.length;i++)
- {
- String keyName=lstName[i].toString();
- Log.e(keyName,b.getString(keyName));
- }
- }
- }
- };
- }
clsReceiver2.java的代碼如下:
- package com.testBroadcastReceiver;
- import android.content.BroadcastReceiver;
- import android.content.Context;
- import android.content.Intent;
- import android.widget.Toast;
- /*
- * 接收靜態注冊廣播的BroadcastReceiver,
- * step1:要到AndroidManifest.xml這裡注冊消息
- * <receiver android:name="clsReceiver2">
- <intent-filter>
- <action
- android:name="com.testBroadcastReceiver.Internal_2"/>
- </intent-filter>
- </receiver>
- step2:定義消息的字符串
- step3:通過Intent傳遞消息來驅使BroadcastReceiver觸發
- */
- public class clsReceiver2 extends BroadcastReceiver{
- @Override
- public void onReceive(Context context, Intent intent) {
- String action = intent.getAction();
- Toast.makeText(context, "靜態:"+action, 1000).show();
- }
- }
上圖是發送Intent至內部動態注冊的BroadcastReceiver,接收到之後顯示消息名稱。動態注冊BroadcastReceiver用到registerReceiver()。
- //當未知Intent包含的內容,則需要通過以下方法來列舉
- Bundle b=intent.getExtras();
- Object[] lstName=b.keySet().toArray();
- for(int i=0;i<lstName.length;i++)
- {
- String keyName=lstName[i].toString();
- Log.e(keyName,String.valueOf(b.get(keyName)));
- }
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