当高度设置为 0dp 时，包含 TextView 的 ScrollView 在 ConstraintLayout 中消失

Answer 1

所以我修复了它，如果你将值设为 match_parent，而不是 0dp，它会起作用：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/white">
    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="A title"
        android:textSize="20dp"
        android:gravity="start"
        android:textColor="#000000"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        />
    <ScrollView
        android:id="@+id/svBody"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true"
        app:layout_constraintTop_toBottomOf="@id/tvTitle"
        app:layout_constraintBottom_toTopOf="@id/btnClose"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        >
        <TextView
            android:id="@+id/tvBody"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="AA text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long.A text that is really long. text that is really long."
            android:textSize="16dp"
            android:textColor="#000000"
            />
    </ScrollView>
    <Button
        android:id="@+id/btnClose"
        android:layout_width="100dp"
        android:layout_height="40dp"
        android:text="close"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_margin="5dp"
        />
</androidx.constraintlayout.widget.ConstraintLayout>

其他选项，使用 PopupWindow 而不是 AlertDialog （您可以像以前一样正常插入的弹出视图）：

    int width = LinearLayout.LayoutParams.MATCH_PARENT;
    int height = LinearLayout.LayoutParams.MATCH_PARENT;
    boolean focusable = true; // lets taps outside the popup also dismiss it
    final PopupWindow popupWindow = new PopupWindow(popupView, width, height, focusable);
        
    // show the popup window
    // which view you pass in doesn't matter, it is only used for the window tolken

popupWindow.showAtLocation(getWindow().getDecorView().findViewById(android.R.id.content), Gravity.CENTER, 0, 0);
        
    // dismiss the popup window when touched
    popupView.setOnTouchListener(new View.OnTouchListener() {
         @Override
         public boolean onTouch(View v, MotionEvent event) {
              popupWindow.dismiss();
              return true;
         }
    });

Answer 2

可能您的对话框没有父级。因此 ConstraintLayout 的 match_parent 不起作用。所以对话框仅限于设置了 wrap_content 的元素。如果您在具有活动的普通片段中显示整个内容，则它可以工作。 因此，我会尝试使用 DialogFragment。在那里它应该可以正常工作。此外，它看起来更漂亮。

相关文档： https://developer.android.com/guide/fragments/dialogs

Answer 3

我认为这应该可以解决您的问题。

https://stackoverflow.com/a/3256305/13303290