Android 视图被线性布局推开

Question

I have a vertical LinearLayout with a TextView , a custom view (replaced with VideoView to illustrate the problem), and a Button . I want the TextView horizontally centered on the top, and the Button horizontally centered on the bottom (as well as vertically centered in the remaining space between VideoView and bottom of the screen). The VideoView should occupy at most the space between the TextView and the Button . However, in my implementation the VideoView pushes the TextView and the Button off of the screen, despite the height being set to wrap_content . Everything works if I set the VideoView height to a manual height. What am I doing wrong? I tried playing around with layout weights but couldn't get anything working.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?android:attr/colorBackground"
    android:clickable="true"
    android:focusable="true"
    android:gravity="center"
    android:orientation="vertical">

    <TextView
        android:id="@+id/titleTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="title"
        android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

    <VideoView
        android:id="@+id/videoView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Space
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="button" />

    <Space
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

Answer 1

Jeff,

I believe it's easier to use constraint layout instead here. The current problem is that you can't determine the size of videoview because it has a wrap_content height

which is trying to take over the whole space in this case

In Constraint layout if you are trying to achieve the following:

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?android:attr/colorBackground"
    android:clickable="true"
    android:focusable="true">

    <TextView
        android:id="@+id/titleTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="title"
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <VideoView
        android:id="@+id/videoView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/titleTextView" />


    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

---

if you are interested on how it should be fixed in LinearLayout I believe you will need to remove all <Space and add the weight to the VideoView