在 broadcast receiver 中直接调用 startActivity，而不加入

FLAG_ACTIVITY_NEW_TASK

这个 flag 的话，将会报错，报错的形式类似如下这样：

java.lang.RuntimeException: Unable to start receiver

XXXX.XXXXX.XXXXX.XXXBroadcastReceiver:

android.util.AndroidRuntimeException:

Calling startActivity() from outside of an Activity

context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?

at android.app.ActivityThread.handleReceiver(ActivityThread.java:2753)

at android.app.ActivityThread.access$1800(ActivityThread.java:156)

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1429)

at android.os.Handler.dispatchMessage(Handler.java:102)

at android.os.Looper.loop(Looper.java:148)

at android.app.ActivityThread.main(ActivityThread.java:5469)

at java.lang.reflect.Method.invoke(Native Method)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

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?

at android.app.ContextImpl.startActivity(ContextImpl.java:675)

at android.app.ContextImpl.startActivity(ContextImpl.java:662)

at android.content.ContextWrapper.startActivity(ContextWrapper.java:331)

at android.content.ContextWrapper.startActivity(ContextWrapper.java:331)

at XXXX.XXXXX.XXXXX.XXXBroadcastReceiver.onReceive(XXXBroadcastReceiver.java:45)

at android.app.ActivityThread.handleReceiver(ActivityThread.java:2741)

at android.app.ActivityThread.access$1800(ActivityThread.java:156)

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1429)

at android.os.Handler.dispatchMessage(Handler.java:102)

at android.os.Looper.loop(Looper.java:148)

at android.app.ActivityThread.main(ActivityThread.java:5469)

at java.lang.reflect.Method.invoke(Native Method)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

这段错误日志中，其实也已经提示我们可能需要使用 FLAG_ACTIVITY_NEW_TASK 参数了：

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?

那么我们就为我们创建的 Intent 对象加上 FLAG_ACTIVITY_NEW_TASK 属性，使其看起来像下面这样：

@Override

public void onReceive(Context context, Intent intent) {

Intent i = new Intent(context, AlarmDialog.class);

i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

context.startActivity(i);

}