java - 我尝试显示DatePickerDialog时出现BadTokenException

单击按钮后，我试图显示DatePickerDialog，但是单击按钮后，它将停止应用程序并引发以下异常：

05-06 08:46:00.688 18786-18786/carloscoronado.chillout E/AndroidRuntime: FATAL EXCEPTION: main
                                                                         Process: carloscoronado.chillout, PID: 18786
                                                                         android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
                                                                             at android.view.ViewRootImpl.setView(ViewRootImpl.java:694)
                                                                             at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:342)
                                                                             at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93)
                                                                             at android.app.Dialog.show(Dialog.java:316)
                                                                             at carloscoronado.chillout.reservar_restaurant$3.onClick(reservar_restaurant.java:188)
                                                                             at android.view.View.performClick(View.java:5612)
                                                                             at android.view.View$PerformClick.run(View.java:22285)
                                                                             at android.os.Handler.handleCallback(Handler.java:751)
                                                                             at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                             at android.os.Looper.loop(Looper.java:154)
                                                                             at android.app.ActivityThread.main(ActivityThread.java:6123)
                                                                             at java.lang.reflect.Method.invoke(Native Method)
                                                                             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
                                                                             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)

这是活动的代码：

public class reservar_restaurant extends AppCompatActivity implements DatePickerDialog.OnDateSetListener{

    int mDay = 0;
    int mMonth = 0;
    int mYear = 0;
    int mHour = 0;
    int mMinute =0;

    Button buttonDate;
    Calendar calender = Calendar.getInstance();

    DatePickerDialog theDatePickerDialog;


    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_reservar_restaurant);

        buttonDate = (Button) findViewById(R.id.btn_fecha);

        Calendar c = Calendar.getInstance();
        mDay = c.get(Calendar.DAY_OF_MONTH);
        mMonth = c.get(Calendar.MONTH);
        mYear = c.get(Calendar.YEAR);
        mHour = c.get(Calendar.HOUR_OF_DAY);
        mMinute = c.get(Calendar.MINUTE);


        buttonDate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //onCreateDialog(DATE_DIALOG_ID);

                long actualDay= calender.getTimeInMillis();
                final long oneDay = 24 * 60 * 60 * 1000L;

                DatePickerDialog datePickerDialog = new DatePickerDialog(
                        getApplicationContext(), reservar_restaurant.this, mYear, mMonth, mMinute);
                datePickerDialog.getDatePicker().setMinDate(actualDay);
                datePickerDialog.getDatePicker().setMaxDate(actualDay+(oneDay*7));
                datePickerDialog.setTitle("Pick your reservation day");
                datePickerDialog.show();

            }
        });
    }


    @Override
    public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
        mYear = year;
        mMonth = month + 1;
        mDay = dayOfMonth;

        String sYear = String.valueOf(mYear);
        String sMonth = String.valueOf(mMonth);
        String sDayOfMonth = String.valueOf(mDay);

        if(sMonth.length() <= 1){
            sMonth = "0" + sMonth;
        }

        if (sDayOfMonth.length() <= 1){
            sDayOfMonth = "0" + sDayOfMonth;
        }

        text7.setText(sDayOfMonth + "/" + sMonth + "/" + sYear );
    }
}

异常使我进入以下代码行：

datePickerDialog.show();

会是什么呢？？

最佳答案

代替：

 DatePickerDialog datePickerDialog = new DatePickerDialog(
                    getApplicationContext(), reservar_restaurant.this, mYear, mMonth, mMinute);

用途：活动上下文

 DatePickerDialog datePickerDialog = new DatePickerDialog(
                        reservar_restaurant.this, reservar_restaurant.this, mYear, mMonth, mMinute);