使用TimePickerDialog时出现空指针异常

Question

java.lang.RuntimeException: Unable to pause activity
Caused by: java.lang.NullPointerException
at android.widget.TimePicker.updateInputState(TimePicker.java:995)
at android.widget.TimePicker.onSaveInstanceState(TimePicker.java:640)
at android.view.View.dispatchSaveInstanceState(View.java:13561)

>

单击

showDialog(END_TIME_PICKER_ID);

受保护得空onPrepareDialog（int id,Dialog Dialog）

  case END_TIME_PICKER_ID :
        endHourOfDay = mEndCalendar.get(Calendar.HOUR_OF_DAY);
         endMinuteOfDay = mEndCalendar.get(Calendar.MINUTE);

        ((TimePickerDialog) dialog).updateTime(endHourOfDay, endMinuteOfDay);
        ((TimePickerDialog) dialog).show();
        break;

受保护的对话框onCreateDialog（int id）

 case END_TIME_PICKER_ID :
  return new TimePickerDialog(this, mEndTimeSetListener, endHourOfDay, endMinuteOfDay, false);

 private TimePickerDialog.OnTimeSetListener mEndTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
public void onTimeSet(TimePicker view, int hourOfDay, int minute)
{
    endHourOfDay = hourOfDay;
    endMinuteOfDay = minute;
 GregorianCalendar endCalendar = (GregorianCalendar) mEndCalendar.clone();
    endCalendar.set(Calendar.DAY_OF_MONTH, mStartCalendar.get(Calendar.DAY_OF_MONTH));
    endCalendar.set(Calendar.HOUR_OF_DAY, endHourOfDay);
    endCalendar.set(Calendar.MINUTE, endMinuteOfDay);
    endCalendar.set(Calendar.SECOND, second);
 }

     java.lang.RuntimeException: Unable to start activity ComponentInfo

如果我对timepickerdialog代码做了什么错误，请告诉我。

Answer 1

我在Android4.4上也遇到过同样的问题，在旧版本上没有发生过。一般而言，我发现这个问题与TimePicker有关。

来自LOGCAT：

E/AndroidRuntime( 8671): java.lang.NullPointerException

E/AndroidRuntime( 8671):    at android.widget. (TimePicker.java:995)

E/AndroidRuntime( 8671):    at android.widget.TimePicker.onSaveInstanceState(TimePicker.java:640)

E/AndroidRuntime( 8671):    at android.view.View.dispatchSaveInstanceState(View.java:13570)

E/AndroidRuntime( 8671):    at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:2813)

E/AndroidRuntime( 8671):    at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:2819)

E/AndroidRuntime( 8671):    at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:2819)

E/AndroidRuntime( 8671):    at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:2819)

E/AndroidRuntime( 8671):    at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:2819)

E/AndroidRuntime( 8671):    at android.view.View.saveHierarchyState(View.java:13553)

E/AndroidRuntime( 8671):    at com.android.internal.policy.impl.PhoneWindow.saveHierarchyState(PhoneWindow.java:1875)

E/AndroidRuntime( 8671):    at android.app.Dialog.onSaveInstanceState(Dialog.java:408)

E/AndroidRuntime( 8671):    at android.app.TimePickerDialog.onSaveInstanceState(TimePickerDialog.java:238)

E/AndroidRuntime( 8671):    at android.app.Activity.saveManagedDialogs(Activity.java:1267)

E/AndroidRuntime( 8671):    at android.app.Activity.performSaveInstanceState(Activity.java:1185)

E/AndroidRuntime( 8671):    at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1241)

E/AndroidRuntime( 8671):    at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3331)

E/AndroidRuntime( 8671):    at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3390)

E/AndroidRuntime( 8671):    at android.app.ActivityThread.access$1100(ActivityThread.java:163)

E/AndroidRuntime( 8671):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1279)

E/AndroidRuntime( 8671):    at android.os.Handler.dispatchMessage(Handler.java:102)

E/AndroidRuntime( 8671):    at android.os.Looper.loop(Looper.java:157)

E/AndroidRuntime( 8671):    at android.app.ActivityThread.main(ActivityThread.java:5335)

E/AndroidRuntime( 8671):    at java.lang.reflect.Method.invokeNative(Native Method)

E/AndroidRuntime( 8671):    at java.lang.reflect.Method.invoke(Method.java:515)

E/AndroidRuntime( 8671):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)

E/AndroidRuntime( 8671):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)

E/AndroidRuntime( 8671):    at dalvik.system.NativeStart.main(Native Method)

我通过添加

<TimePicker android:id="@+id/timePicker"     
     android:layout_width="wrap_content"    
     android:layout_height="wrap_content"    
     android:layout_gravity="center_horizontal"
android:descendantFocusability="blocksDescendants">  
 <requestFocus />  
</TimePicker>  

timePicker = (TimePicker) viewContent.findViewById(R.id.timePicker);
timePicker.setIs24HourView(true);
timePicker.setOnTimeChangedListener(listener);