android - 我无法从我的 Intent 中获取 Extras？

Question

我使用 AlarmManager 通过 PendingIntent 启动 Activity 。

        Intent smon = new Intent(ctxt, VideoActivty.class);
        final Bundle extra = new Bundle();
        extra.putString("extrastring","monday");
        smon.putExtras(extra);
        //smon.putExtra("extrastring","monday");
        smon.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
        PendingIntent psmon = PendingIntent.getActivity(ctxt, 0, smon, 0);

        Calendar calSet1 = Calendar.getInstance();
        calSet1.set(Calendar.MONTH, c.get(Calendar.MONTH));
        calSet1.set(Calendar.YEAR, c.get(Calendar.YEAR));
        calSet1.set(Calendar.DAY_OF_WEEK, 2);
        calSet1.set(Calendar.HOUR_OF_DAY, hsmon);
        calSet1.set(Calendar.MINUTE, msmon);
        calSet1.set(Calendar.SECOND, 0);
        calSet1.set(Calendar.MILLISECOND, 0);
        int delay1=0;
        if(today.get(Calendar.DAY_OF_WEEK)>2)delay1=7 * 24 * 60 * 60 * 1000;
        if((today.get(Calendar.DAY_OF_WEEK)==2)&&(today.get(Calendar.HOUR_OF_DAY)>hsmon))delay1=7 * 24 * 60 * 60 * 1000;
        if((today.get(Calendar.DAY_OF_WEEK)==2)&&(today.get(Calendar.HOUR_OF_DAY)==hsmon)&&(today.get(Calendar.MINUTE)>msmon))delay1=7 * 24 * 60 * 60 * 1000;
        Log.e("delay 1",Integer.toString(delay1));
        //calSet.setTimeZone(TimeZone.getTimeZone("UTC"));
        mgr.setRepeating(AlarmManager.RTC_WAKEUP, calSet1.getTimeInMillis()+delay1,
                7 * 24 * 60 * 60 * 1000, psmon);

如您所见，我的 Intent 中有一个 Extra:“extrastring”。

现在，当我尝试从启动的 Activity 中读取 Extra 时:

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //
    final Bundle extra = getIntent().getExtras();
    String message="cazzo";
    if (extra != null) {

        message=extra.getString("extrastring");
    }
    Log.e("intent che è partito",message);

我得到一个 NullPointerException。

感谢您的帮助

07-19 13:34:18.336: E/AndroidRuntime(14109): FATAL EXCEPTION: main
07-19 13:34:18.336: E/AndroidRuntime(14109): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.videdrome/com.example.videdrome.VideoActivty}: java.lang.NullPointerException: println needs a message
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.os.Looper.loop(Looper.java:137)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread.main(ActivityThread.java:5041)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at java.lang.reflect.Method.invokeNative(Native Method)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at java.lang.reflect.Method.invoke(Method.java:511)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at dalvik.system.NativeStart.main(Native Method)
07-19 13:34:18.336: E/AndroidRuntime(14109): Caused by: java.lang.NullPointerException: println needs a message
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.util.Log.println_native(Native Method)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.util.Log.e(Log.java:231)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at com.example.videdrome.VideoActivty.onCreate(VideoActivty.java:41)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.Activity.performCreate(Activity.java:5104)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
07-19 13:34:18.336: E/AndroidRuntime(14109):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
07-19 13:34:18.336: E/AndroidRuntime(14109):    ... 11 more

Answer 1

我一直在使用 Bundle 做类似的事情

final Intent notificationIntent = new Intent(context, A.class);
notificationIntent.putExtras(extra);
final PendingIntent intent = PendingIntent.getActivity(context, 0,
        notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

其中 extra 是 Bundle :

final Bundle extra = new Bundle();
extra.putString("Message", "hello");

您可以在启动的 Activity 的 onCreate 中检索 Bundle 的值:

final Bundle extra = getIntent().getExtras();
if (extra != null) {
    String message=extra.getString("Message");
}

此外，您可以使用标志 PendingIntent.FLAG_UPDATE_CURRENT

这个标志是这样工作的:

如果描述的 PendingIntent 已经存在，则保留它，但用这个新 Intent 中的内容替换它的额外数据。如果您正在创建只有 extras 发生变化的 intents，并且不关心收到您之前的 PendingIntent 的任何实体将能够使用您的新 extras 启动它，即使它们没有明确提供给它，也可以使用它。