ListView空视图不会显示

Posted 2021-04-16

当我设置list.setEmptyView(empty)时，列表背景颜色为白色，我找不到绿色的文本视图，但如果我对此行进行注释，则列表背景颜色将为青色。

addedItems数组：

String[] addedItems = {};

这是loadList功能：

private void loadList() {
    ListView list = findViewById(R.id.list);
    if(addedItems != null) {
        itemsAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, addedItems);
        list.setAdapter(itemsAdapter);
        TextView empty = new TextView(this);

        empty.setText("The list is empty");
        empty.setBackgroundColor(Color.GREEN);
        list.setEmptyView(empty);

        list.setBackgroundColor(Color.CYAN);
    }
} 

这是我的main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
tools:context="ir.vahid.actionbarmenu.MainActivity">

<ListView
    android:id="@+id/list"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    >
</ListView>

</android.support.constraint.ConstraintLayout>

答案

手动（膨胀）将空视图添加到Listview的“父”视图：

ListView my_list = (ListView) findViewById(R.id.my_list);
View emptyView = getLayoutInflater().inflate(R.layout.empty_view,null);
((ViewGroup)my_list.getParent()).addView(emptyView); 
listView.setEmptyView(emptyView);

要么

您的TextView应放在ListView项目的正下方，其可见性设置为已消失

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
tools:context="ir.vahid.actionbarmenu.MainActivity">

<ListView
    android:id="@+id/list"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    >
</ListView>

<TextView
        android:id="@+id/empty_list_item"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone"
        android:text="@string/emptyList" >
</TextView>

</android.support.constraint.ConstraintLayout>