Content的startActivity方法需添加FLAG_ACTIVITY_NEW_TASK flag

最新推荐文章于 2024-08-02 23:25:07 发布

最新推荐文章于 2024-08-02 23:25:07 发布 · 222 阅读

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本文讨论了一个在Android应用中遇到的问题，即在BootBroadcastReceiver中尝试通过startActivity启动另一个Activity时，收到了一个运行时异常。问题在于未在Activity上下文中调用startActivity，因此需要添加FLAG_ACTIVITY_NEW_TASK标志来解决。

Android 2.3.3 Eclipse Version: 3.7.0 LogCat

BootBroadcastReceiver继承自android.content.BroadcastReceiver，处理广播事件，部分代码如下：

public void onReceive(Context context, Intent intent) { …… Intent startTaobao = new Intent(context, Start.class); context.startActivity(startTaobao); …… }

LogCat 报错信息：

02-10 17:13:20.417: DEBUG/AndroidRuntime(5066): Shutting down VM 02-10 17:13:20.417: WARN/dalvikvm(5066): threadid=1: thread exiting with uncaught exception (group=0x40015560) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): FATAL EXCEPTION: main 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): java.lang.RuntimeException: Unable to start receiver com.taobao.nokia.BootBroadcastReceiver: android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want? 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ActivityThread.handleReceiver(ActivityThread.java:1805) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ActivityThread.access$2400(ActivityThread.java:117) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:981) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.os.Handler.dispatchMessage(Handler.java:99) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.os.Looper.loop(Looper.java:123) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ActivityThread.main(ActivityThread.java:3683) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at java.lang.reflect.Method.invokeNative(Native Method) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at java.lang.reflect.Method.invoke(Method.java:507) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at dalvik.system.NativeStart.main(Native Method) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): Caused by: android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want? 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ContextImpl.startActivity(ContextImpl.java:621) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.content.ContextWrapper.startActivity(ContextWrapper.java:258) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.content.ContextWrapper.startActivity(ContextWrapper.java:258) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at com.taobao.nokia.BootBroadcastReceiver.onReceive(BootBroadcastReceiver.java:64) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): at android.app.ActivityThread.handleReceiver(ActivityThread.java:1794) 02-10 17:13:20.448: ERROR/AndroidRuntime(5066): ... 10 more 02-10 17:13:20.478: WARN/ActivityManager(68): Force finishing activity com.taobao.nokia/.Start

主要错误：

02-10 17:13:20.448: ERROR/AndroidRuntime(5066): Caused by: android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?

发生错误原因分析：

Content的startActivity方法，需要开启一个新的task。如果使用 Activity的startActivity方法，不会有任何限制，因为Activity继承自Context，重载了startActivity方法。

解决办法：

按照错误提示，添加一个FLAG_ACTIVITY_NEW_TASK flag

public void onReceive(Context context, Intent intent) { …… Intent startTaobao = new Intent(context, Start.class); startTaobao.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(startTaobao); …… }