Question

好日子，大家好，我希望你没事我的问题是我收到了下面所述的错误我试图创建一个警报对话框，其中有一个CalendarView和Timepicker我试图从calendarview和datepicker获取日期并将其传递给firebase云火库。
我的代码：

AlertDialog.Builder dialog= new AlertDialog.Builder(Negociation.this);
            View mView=getLayoutInflater().inflate(R.layout.dialog_negociation,null);
            dialog.setView(mView);
            final Calendar calendar = Calendar.getInstance();

            dialog.setTitle("Modifier les modalitées de livraison:");
            dialog.setNegativeButton("sortir", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            }).setPositiveButton("Envoyer", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    negociationprogressbar.setVisibility(View.VISIBLE);
                    CalendarView mCalendar=(CalendarView)findViewById(R.id.nouvelledateNegociation);
                    final TimePicker mTime=(TimePicker) findViewById(R.id.nouvelleheureNegociation);
                    mCalendar.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
                        @Override
                        public void onSelectedDayChange(@NonNull CalendarView view, final int year, final int month, final int dayOfMonth) {

                            mTime.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
                                @Override
                                public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {
                                    calendar.set(year,month,dayOfMonth,hourOfDay,minute);
                                }
                            });

                        }
                    });
                    Map<String,Object> Negociationmap=new HashMap<>();
                    String message="Le pharmacien "+nomPh+" a proposé d'autre horaire pour la livraison concernant le formulaire envoyée le: "+Dateenvoi+"\n"+"Le jour et l'heure proposés : "+datecreation(calendar.getTime());
                    Negociationmap.put("Message",message);
                    Negociationmap.put("Validation",false);
                    Negociationmap.put("PharmacienID",User_id);
                    mFirestore.collection("Clients/"+Client+"/Negociations").add(Negociationmap).addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
                        @Override
                        public void onSuccess(DocumentReference documentReference) {
                            Toast.makeText(Negociation.this, "Le message est envoyé", Toast.LENGTH_SHORT).show();
                        }
                    }).addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            Toast.makeText(Negociation.this, "Echec d'envoi", Toast.LENGTH_SHORT).show();
                        }
                    });

                }
            });
            dialog.show();


        }
    });

}

XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:id="@+id/negociationTextView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="15sp"
            android:fontFamily="@font/nunito_light"
            android:padding="5sp"
            android:text="Choisissez le jour et l'heure préférés"
            android:textSize="20sp" />

        <CalendarView
            android:id="@+id/nouvelledateNegociation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15sp"
            android:background="@drawable/logout_button"
            android:backgroundTint="@android:color/holo_red_light"
            android:dateTextAppearance="@style/CalenderViewDateCustomText"
            android:fontFamily="@font/nunito_light"
            android:theme="@style/CalenderViewCustom"
            android:weekDayTextAppearance="@style/CalenderViewWeekCustomText" />

        <TimePicker
    android:id="@+id/nouvelleheureNegociation"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:fontFamily="@font/nunito_light"
    android:theme="@style/myTimePickerStyle"
    android:layout_margin="15sp"

    />
    </LinearLayout>

</ScrollView>

错误：

beginning of crash
05-31 12:35:35.316 2891-2891/? E/AndroidRuntime: FATAL EXCEPTION: main
                                             Process: comi.example.youyo.medicom, PID: 2891
                                             java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.CalendarView.setOnDateChangeListener(android.widget.CalendarView$OnDateChangeListener)' on a null object reference
                                                 at comi.example.youyo.medicom.Negociation$3.onClick(Negociation.java:123)
                                                 at android.view.View.performClick(View.java:5609)
                                                 at android.view.View$PerformClick.run(View.java:22259)
                                                 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:6077)
                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

显示我想要做的图像：

Answer 1

更改此行

 CalendarView mCalendar=(CalendarView)findViewById(R.id.nouvelledateNegociation);
 final TimePicker mTime=(TimePicker) findViewById(R.id.nouvelleheureNegociation);

到

 CalendarView mCalendar=(CalendarView)mView.findViewById(R.id.nouvelledateNegociation);
 final TimePicker mTime=(TimePicker) mView.findViewById(R.id.nouvelleheureNegociation);

findViewById方法会从Activity的contentview中找到一个视图。要从特定ViewGroup来电View.findViewById

中查找视图

Answer 2

试试这个：

public Dialog onCreateDialog(Bundle onSaveInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = getActivity().getLayoutInflater();
        View v= inflater.inflate(R.layout.calendarpopup, null);
        final CalendarView cal= 
       (CalendarView)v.findViewById(R.id.calendarView1);

警报对话框CalendarView NullpointException

2 个答案: