Question

我有一个活动有2个按钮 - 一个用于DatePicker和一个TimePicker。当我选择应用程序崩溃的时间并给出空指针异常时。我认为它发生在我的ActivityResult方法中，但不确定，因为我不理解logcat错误。如果我在错误的位置查找错误，我可以提供更多代码。任何帮助都会很棒。 Thansk。

这是logcat：

04-28 12:18:01.676  13968-13968/com.pctoolman.planme.app W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-28 12:18:01.766  13968-13968/com.pctoolman.planme.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
        at java.util.Calendar.setTime(Calendar.java:1320)
        at android.text.format.DateFormat.format(DateFormat.java:438)
        at com.pctoolman.planme.app.NewEventSetupFragment.updateDate(NewEventSetupFragment.java:36)
        at com.pctoolman.planme.app.NewEventSetupFragment.onActivityResult(NewEventSetupFragment.java:56)
        at com.pctoolman.planme.app.TimePickerFragment.sendResult(TimePickerFragment.java:45)
        at com.pctoolman.planme.app.TimePickerFragment.access$100(TimePickerFragment.java:22)
        at com.pctoolman.planme.app.TimePickerFragment$2.onClick(TimePickerFragment.java:92)
        at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5041)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
        at dalvik.system.NativeStart.main(Native Method)
     04-28 12:18:58.726  13968-13968/com.pctoolman.planme.app I/Process﹕ Sending signal. PID: 13968 SIG: 9
   04-28 12:18:59.876  14006-14006/com.pctoolman.planme.app E/Trace﹕ error opening trace file: No such file or directory (2)

这是我的ActivityResult方法。

 private static final String DIALOG_DATE = "date";
private static final int REQUEST_DATE = 0;
private static final int REQUEST_TIME = 0;

public void updateDate() {
    mEventDateButton.setText(DateFormat.format("EEEE, MMM dd, yyyy", mEvent.getDate()).toString());
}

public void updateTime() {
    mEventTimeButton.setText(mEvent.getTime().toString());
}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mEvent = new Event();
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode != Activity.RESULT_OK) return;;
    if (requestCode == REQUEST_DATE) {
        Date date = (Date)data.getSerializableExtra(DatePickerFragment.EXTRA_DATE);
        mEvent.setDate(date);
        updateDate();
    } else if(requestCode == REQUEST_TIME){
        Date time = (Date)data.getSerializableExtra(TimePickerFragment.EXTRA_TIME);
        mEvent.setTime(time);
        updateTime();
    }
}

newEventSetupFragment的第36行

public void updateDate() {
    mEventDateButton.setText(DateFormat.format("EEEE, MMM dd, yyyy", mEvent.getDate()).toString());


}

event.java 公共课活动{

private UUID mId;
private String mEventNameTitle;
private Date mDate;
private Date mTime;

public Event() {
    //generate uniques identifier
    mId=UUID.randomUUID();

    //generate date
    mDate = new Date();

    //generate time
    mTime = new Date();
}

public UUID getId() {
    return mId;
}

//event name title getter and setter
public String getTitle() {
    return mEventNameTitle;
}

public void setTitle(String title){
    mEventNameTitle = title;
}

//event date getter and setter
public Date getDate() {
    return mDate;
}

public void setDate(Date date) {
    mDate = date;
}

//event time getter and setter
public Date getTime() {
    return mTime;
}

public void setTime (Date time) {
    mTime = time;
}

}

mEventDate和mEventTime按钮

   event date button set
    mEventDateButton = (Button)v.findViewById(R.id.eventDateButton);
    updateDate();
    mEventDateButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            FragmentManager fm =getActivity().getSupportFragmentManager();
            DatePickerFragment dialog =  DatePickerFragment.newInstance(mEvent.getDate());
            dialog.setTargetFragment(NewEventSetupFragment.this, REQUEST_DATE);
            dialog.show(fm, DIALOG_DATE);
        }
    });

    //event time button set
    mEventTimeButton = (Button)v.findViewById(R.id.eventTimeButton);
    updateTime();
    mEventTimeButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            FragmentManager fm = getActivity().getSupportFragmentManager();
            TimePickerFragment dialog = TimePickerFragment.newInstance(mEvent.getTime());
            dialog.setTargetFragment(NewEventSetupFragment.this,REQUEST_TIME);
            dialog.show(fm, DIALOG_DATE);

活动结果if / else语句

0 个答案: