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问OnReceive in BroacdcastReceiver返回意图与额外但不能提取
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Stack Overflow用户

提问于 2014-10-18 23:31:56

回答 1查看 775关注 0票数 0

问题

我不知道为什么logcat给我一个NPE，因为它的意图不是空的，并且在onReceive()中有额外的内容，所以请帮助我找出并指导我一些事情。

注意事项

我在这个项目中有多个广播接收器。
我用唯一的ID注册它们。

Logcat (证明它有额外的)

10-19 06:10:32.587  31593-31593/com.bis.prototype.airdroid E/BroadcastReceiver_CalibrateMode﹕ Intent { flg=0x14 cmp=com.bis.prototype.airdroid/.BroadcastReceiver_CalibrateMode (has extras) }

BroadcastReceiver_CalibrateMode.class

public class BroadcastReceiver_CalibrateMode extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {


        Log.e("BroadcastReceiver_CalibrateMode", String.valueOf(intent));
        String slot = intent.getExtras().getString("NODE_SLOT");
        Log.e("BroadcastReceiver_CalibrateMode", slot); // NPE ON THIS LINE

        Intent calibrateIntent = new Intent(context, Service_MQTTPush.class);
        calibrateIntent.putExtra("CALIBRATE_MODE",true);
        calibrateIntent.putExtra("NODE_SLOT", slot);
        context.startService(calibrateIntent);
    }
}

LogCat

java.lang.RuntimeException: Unable to start receiver com.bis.prototype.airdroid.BroadcastReceiver_CalibrateMode: java.lang.NullPointerException: println needs a message
        at android.app.ActivityThread.handleReceiver(ActivityThread.java:2476)
        at android.app.ActivityThread.access$1700(ActivityThread.java:144)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1322)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:212)
        at android.app.ActivityThread.main(ActivityThread.java:5135)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException: println needs a message
        at android.util.Log.println_native(Native Method)
        at android.util.Log.e(Log.java:232)
        at com.bis.prototype.airdroid.BroadcastReceiver_CalibrateMode.onReceive(BroadcastReceiver_CalibrateMode.java:17)
        at android.app.ActivityThread.handleReceiver(ActivityThread.java:2469)
            at android.app.ActivityThread.access$1700(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1322)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:212)
            at android.app.ActivityThread.main(ActivityThread.java:5135)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
            at dalvik.system.NativeStart.main(Native Method)

代码，我注册我的广播

public static void registerAlarm_calibrateMode(Context context){

        for (int i = 0; i < NODE_SLOT.length; i++) {

            Log.e("registerAlarm_calibrateMode", NODE_SLOT[i]+" :: "+getNodeSerial(context,NODE_SLOT[i]));

            if (!getNodeSerial(context,NODE_SLOT[i]).equals("null")) {

                Intent intent = new Intent(context, BroadcastReceiver_CalibrateMode.class);
                Log.e("registerAlarm_calibrateMode", "putExtra-->"+NODE_SLOT[i]);
                intent.putExtra("NODE_SLOT", NODE_SLOT[i]);
                PendingIntent pi = PendingIntent.getBroadcast(
                        context,
                        GET_NODE_BROADCAST_ID_FOR_CALIBRATE_MODE[getNodeID(NODE_SLOT[i])],
                        intent,
                        Intent.FILL_IN_DATA
                );
                AlarmManager alarm = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);

                Calendar now = Calendar.getInstance();
                now.add(Calendar.MINUTE,1);

                if (android.os.Build.VERSION.SDK_INT < 19) {
                    alarm.set(AlarmManager.RTC_WAKEUP, now.getTimeInMillis(), pi);
                } else {
                    alarm.setExact(AlarmManager.RTC_WAKEUP,now.getTimeInMillis(),pi);
                }
            }
        }
    }

XML清单

    <receiver android:name=".BroadcastReceiver_SleepMode"/>
    <receiver android:name=".BroadcastReceiver_Location"/>
    <receiver android:name=".BroadcastReceiver_CalibrateMode"/>
    <receiver android:name=".BroadcastReceiver_TempLog"/>

android-intent

nullpointerexception

broadcastreceiver

android

回答 1

Stack Overflow用户

发布于 2014-12-04 19:54:31

替换流动代码BroadcastReceiver_CalibrateMode.java

public class BroadcastReceiver_CalibrateMode extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {


        Log.e("BroadcastReceiver_CalibrateMode", String.valueOf(intent));
        String slot = intent.getExtras().getString("NODE_SLOT");
        Log.e("BroadcastReceiver_CalibrateMode", slot); // NPE ON THIS LINE

        Intent calibrateIntent = new Intent(context, Service_MQTTPush.class);
        calibrateIntent.putExtra("CALIBRATE_MODE",true);
        calibrateIntent.putExtra("NODE_SLOT", slot);

        calibrateIntent .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); // SPCIAL CODE

        context.startService(calibrateIntent);
    }
}

当调用startActivity时，新活动将与调用者位于同一个屏幕堆栈(上下文)中。有时，调用方可能没有活动上下文，例如，从Broadcastreceive.onReceive()方法启动活动或从服务启动活动。在这些情况下，调用FLAG_ACTIVITY_NEW_TASK"，将导致“从活动上下文外部调用startActivity()”的例外情况，因为新的活动不存在上下文。

为了解决这个问题，将FLAG_ACTIVITY_NEW_TASK设置为以下意图，然后将为新活动创建一个新的上下文。

myIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

票数 2

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/26445642

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