Question

问题

我不知道为什么logcat会给我一个NPE，因为意图不是null并且在onReceive（）中有额外的所以，请帮我找出并指导我的事情。

注意

我在这个项目中有多个广播接收器。
我使用具有唯一ID的Pending Intent注册它们。

Logcat（证明它有额外的内容）

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的

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)

我注册广播的代码

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 MANIFEST

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

Answer 1

替换流动的代码 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);
    }
}

调用startActivity时，新活动将与调用者位于同一屏幕堆栈（上下文）中。有时，调用者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startActivity将导致“从Activity活动上下文调用startActivity（）”的异常需要 FLAG_ACTIVITY_NEW_TASK “，因为新活动没有生成的上下文。

要解决此问题，请按如下方式将FLAG_ACTIVITY_NEW_TASK设置为意图，然后将为新活动创建新的上下文。

myIntent.setFlags（Intent.FLAG_ACTIVITY_NEW_TASK）;

BroacdcastReceiver中的OnReceive返回意图有额外但无法提取

1 个答案: