java为什么在片段对话框中ListView总是空的

Question

对话框正确显示，但listview始终为空。 以下是我启动活动时得到的信息 enter image description here

public class MainFragment extends Fragment {
    String[] cities = {"Tanger", "Meknes", "Casablanca",
            "Fes", "Tetouan", "Taza", "Rabat"};
    Dialog dialog;
  
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        TextView currentCity = view.findViewById(R.id.city);
        currentCity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dialog = new Dialog(getContext());
                dialog.setContentView(R.layout.dialog_searchable_spinner);
                dialog.getWindow().setLayout(800, 1000);
                View spinnerView = getLayoutInflater().inflate(R.layout.dialog_searchable_spinner, container, false);
                dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                dialog.show();
                EditText searchTextView = spinnerView.findViewById(R.id.editText);
                ListView citiesListView = spinnerView.findViewById(R.id.citiesListView);
                ArrayAdapter<String> adapter = new ArrayAdapter<>(getActivity(), 安卓.R.layout.simple_list_item_1, cities);
                citiesListView.setAdapter(adapter);
}

Answer 1

对话框布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/alert_dialog"
    android:padding="16dp"
    android:orientation="vertical"
    android:gravity="center">


    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="البحث عن المدينة"
        android:textSize="25sp"
        android:textColor="@color/primaryColor"
        android:fontFamily="@font/alhurra"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:background="@android:drawable/editbox_background"
        android:hint="إسم المدينة..."
        android:fontFamily="@font/aj_bold"
        android:textDirection="rtl"
        android:layoutDirection="rtl"
        android:padding="10dp"
        android:singleLine="true"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <ListView
        android:id="@+id/citiesListView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginTop="5dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:layout_editor_absoluteX="16dp" />



</androidx.constraintlayout.widget.ConstraintLayout>

碎片布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/activitybackground"
    tools:context=".MainFragment">


            <TextView
                android:id="@+id/city"
                android:layout_width="120dp"
                android:layout_height="wrap_content"
                android:layout_margin="5dp"
                android:layout_weight="1"
                android:fontFamily="@font/alhurra"
                android:gravity="center"
                android:text="مكنـاس"
                android:textColor="@color/primaryColor"
                android:textSize="20sp" />

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 2

你的布局有问题ConstraintLayout以某种方式隐藏了listview。您必须对布局文件进行一些更改。例如，我使用LinearLayout就可以做到这一点

        Dialog dialog;
        dialog = new Dialog(this);
        dialog.setContentView(R.layout.dialog_searchable_spinner);
        dialog.getWindow().setLayout(800, 1000);
        //View spinnerView = getLayoutInflater().inflate(R.layout.dialog_searchable_spinner,binding.getRoot());
        //dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

        ListView citiesListView = dialog.findViewById(R.id.citiesListView);
        ArrayAdapter<String> adapter = new ArrayAdapter<>(getApplicationContext(), android.R.layout.simple_list_item_1, cities);
        citiesListView.setAdapter(adapter);
        dialog.show();

==

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    android:gravity="center">


    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="البحث عن المدينة"
        android:textSize="25sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editText"
        android:layout_below="@id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:background="@android:drawable/editbox_background"
        android:hint="إسم المدينة..."
        android:textDirection="rtl"
        android:layoutDirection="rtl"
        android:padding="10dp"
        android:singleLine="true"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <ListView
        android:id="@+id/citiesListView"
        android:layout_below="@id/editText"
        android:layout_width="match_parent"
        android:layout_height="400dp"
        android:layout_marginTop="5dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:layout_editor_absoluteX="16dp" />



</RelativeLayout>