Android View 永远不会变得不可见

Question

我试图让我的一些观点不可见。这是 XML 代码:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">


    <Button
            android:text="See More Like This"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/recommender"
            tools:visibility="invisible"
            android:layout_marginEnd="24dp" android:layout_marginRight="24dp" android:layout_marginBottom="20dp"
            app:layout_constraintEnd_toEndOf="parent" app:layout_constraintBottom_toTopOf="@+id/imageView"/>
    <TextView
            android:text="https://www.google.com"
            android:layout_width="169dp"
            android:layout_height="50dp"
            android:autoLink="web"
            android:linksClickable="true"
            android:id="@+id/urlDisplay"
            tools:visibility="invisible"
            app:layout_constraintTop_toTopOf="parent" app:layout_constraintStart_toStartOf="parent"
            android:layout_marginLeft="24dp" android:layout_marginTop="101dp" android:layout_marginStart="24dp"/>

    <TextView
            android:text="TextView"
            android:layout_width="0dp"
            android:layout_height="59dp"
            android:id="@+id/comicTitle" tools:visibility="invisible"
            android:layout_marginTop="21dp" android:layout_marginBottom="21dp" app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toTopOf="@+id/urlDisplay" app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent" android:layout_marginLeft="40dp"
            android:layout_marginStart="40dp" android:layout_marginEnd="40dp" android:layout_marginRight="40dp"/>

</android.support.constraint.ConstraintLayout>

除了样板文件外，没有任何 Kotlin 代码。当我启动应用程序时，我的所有 View 都是可见的。我不明白这是怎么发生的，因为我已经明确地将它们设置为在 xml 中不可见。

如何让它们不可见？

Answer 1

阅读Tools attributes reference

Android Studio supports a variety of XML attributes in the tools namespace that enable design-time features (such as which layout to show in a fragment) or compile-time behaviors (such as which shrinking mode to apply to your XML resources). When you build your app, the build tools remove these attributes so there is no effect on your APK size or runtime behavior.

你应该使用 android:visibility="invisible" 而不是 tools:visibility="invisible"