原理
當Android系統完成BOOT階段之後,就會發送壹條名為 ACTION_BOOT_COMPLETED 的廣播,我們便可在壹個BroadcastReceiver中捕獲這條廣播,然後啟動我們的Activity或者Service,當然要註意的是,我們的application必須具有捕獲該廣播的權限,下面請看具體步驟:
步驟壹首先要有壹個用於開機啟動的Activity或者Service,這裏以系統自己創建的最簡單的Activity為例進行講解。
package com.billhoo.study;
import android.app.Activity;
import android.os.Bundle;
public class BootTestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
步驟二我們要編寫壹個BroadcastReceiver用以捕獲ACTION_BOOT_COMPLETED這條廣播,並在捕獲之後啟動我們要啟動的Activity。
註意:必須在intent中添加Intent.FLAG_ACTIVITY_NEW_TASK標記,這就是我之前老是啟動失敗的原因。至於為什麽,我還在研究SDK doc,明白了之後就回來補上。
package com.billhoo.study;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class BootCompletedReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED))
{
Intent newIntent = new Intent(context, BootTestActivity.class);
newIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);? //註意,必須添加這個標記,否則啟動會失敗
context.startActivity(newIntent);?
}?
}
}
步驟三在AndroidManifest.xml配置文件中註冊我們的BroadcastReceiver
<receiver android:name=".BootCompletedReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
步驟四在AndroidManifest.xml配置文件中添加允許我們捕獲該廣播的權限
<!-- permissions -->
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
之前把uses-permission 打錯成permission ,結果壹直提示下面這個錯誤:Permission Denial: receiving Intent { act=android.intent.action.BOOT_COMPLETED flg=0x8000010 (has extras) } to com.example.boottest/.BootCompletedReceiver requires android.permission.RECEIVE_BOOT_COMPLETED due to sender null (uid 1000)
重啟虛擬機,大功告成。
下面附上完成的AndroidManifest.xml,以便大家理解參考
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="/apk/res/android"
package="com.billhoo.study" android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4" />
<!-- permissions -->
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<!-- activities -->
<activity android:name=".BootTestActivity" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!-- receivers -->
<receiver android:name=".BootCompletedReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
</application>
</manifest>