java.lang.NullPointerException while設置時間

Question

TimePicker出現，但是當我嘗試選擇時間。它引發了我下面的例外。

TimeFragment類。

import java.util.Calendar; 
import com.actionbarsherlock.app.SherlockDialogFragment; 
import android.app.Dialog; 
import android.app.TimePickerDialog; 
import android.content.Context; 
import android.os.Bundle; 
import android.text.format.DateFormat; 
import android.widget.TimePicker; 

public class TimePickerFragment extends SherlockDialogFragment implements TimePickerDialog.OnTimeSetListener 
{ 
    private TimePickedListener mListener; 
    static int hour; 
    static int minute; 
    static Context mContext; 

    public static TimePickerFragment newInstance(Context context, TimePickedListener listener, Calendar now) 
    { 
     TimePickerFragment dialog = new TimePickerFragment(); 
     mContext = context; 
     hour = now.get(Calendar.HOUR_OF_DAY); 
     minute = now.get(Calendar.MINUTE); 

     return dialog; 
    } 

    @Override 
    public Dialog onCreateDialog(Bundle savedInstanceState) 
    { 
     return new TimePickerDialog(mContext, this, hour, minute, DateFormat.is24HourFormat(getActivity())); 
    } 

    @Override 
    public void onTimeSet(TimePicker view, int hourOfDay, int minute) 
    { 
     // when the time is selected, send it to the activity via its callback 
     // interface method 
     Calendar c = Calendar.getInstance(); 
     c.set(Calendar.HOUR_OF_DAY, hourOfDay); 
     c.set(Calendar.MINUTE, minute); 

     mListener.onTimePicked(c); 
    } 

    public static interface TimePickedListener 
    { 
     public void onTimePicked(Calendar time); 
    } 
} 

選擇時間主要碎片內

public void selectTime(final TextView lblTime, final int position) { 
    hideRight(); 
    timeFrag = TimePickerFragment.newInstance(getActivity(), new TimePickedListener() {@ 
     Override 
     public void onTimePicked(Calendar time) { 
      lblTime.setText(DateFormat.format("h:mm a", time)); 
     } 
    }, now); 
    timeFrag.show(getActivity().getSupportFragmentManager(), "timePicker"); 
} 

07-02 17：28：04.214：E/XXX（10341）：未捕獲的例外情況是：07-02 17：28：04.214 ：E/XXX（10341）：java.lang.NullPointerException 07-02 17：28：04.214：E/XXX（10341）：at com.common.TimePickerFragment.onTimeSet（TimePickerFragment.java:47） 07-02 17：28：04.214：E/XXX（10341）：at android.app.TimePickerDialog.tryNotifyTimeSet（Tim ePickerDialog.java:130） 07-02 17：28：04.214：E/XXX（10341）：at android.app.TimePickerDialog.onClick（TimePickerDialog.java:115）07-02 17：28：04.214：E/XXX（10341）：at com.android.internal.app.AlertController $ ButtonHandler.handleMessage（AlertController.java:166） 07-02 17：28：04.214：E/XXX（10341）：at android.os .Handler.dispatchMessage（Handler.java:99）07-02 17：28：04.214：E/XXX（10341）：at android.os.Looper.loop（Looper.java:137）07-02 17:28 ：04.214： E/XXX（10341）：at android.app.ActivityThread.main（ActivityThread.java:4928）07-02 17：28：04.214：E/XXX（10341）：at java.lang。反映。方法.invokeNative（本地方法）07-02 E/XXX（10341）：at（0334）：17/28 com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:791） 07-02 17：28：04.214：E/XXX（10341）：at com.android.internal.os.ZygoteInit。主（ZygoteInit.java:558）07-02 17：28：04.214：E/XXX（10341）：在dalvik.system.NativeStart.main（本地 法）

Answer 1

你忘了初始化private TimePickedListener mListener;

更改您的newInstance法：

public static TimePickerFragment newInstance(Context context, TimePickedListener listener, Calendar now) 
    { 
     TimePickerFragment dialog = new TimePickerFragment(); 
     mContext = context; 
     mListener = listener; 
     hour = now.get(Calendar.HOUR_OF_DAY); 
     minute = now.get(Calendar.MINUTE); 

     return dialog; 
    } 

Answer 2

你沒有實例private TimePickedListener mListener;任何地方。它參考null。

public static TimePickerFragment newInstance(Context context, TimePickedListener listener, Calendar now) 
{ 
    TimePickerFragment dialog = new TimePickerFragment(); 
    mContext = context; 
    hour = now.get(Calendar.HOUR_OF_DAY); 
    minute = now.get(Calendar.MINUTE); 
    mListener = listener; // you missed this line 
    return dialog; 
}