java - Android 图像按钮不显示

Question

图像按钮没有显示在我的应用程序中，但该按钮仍然可点击，其点击日志有效。

这是按钮:

<ImageButton
    android:id="@+id/stopStream"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_margin="10dp"
    android:background="@drawable/cancel_btn"
    android:contentDescription="@string/stop_stream"
    android:onClick="hangup"
    android:visibility="visible" />

Android Studio 确实显示了可绘制图标和左侧工具栏，因此图像的路径是正确的。首先我想到了 z-index 错误(我来自网络世界)。但据我所知，android 中并没有真正的 z-index 来给出标签。什么可能进一步导致此问题

<RelativeLayout 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:color/black"
    tools:context="de.app.test.VideoChatActivity">

    <android.opengl.GLSurfaceView
        android:id="@+id/gl_surface"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone" />

    <ImageButton
        android:id="@+id/stopStream"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:background="@drawable/cancel_btn"
        android:contentDescription="@string/stop_stream"
        android:onClick="hangup"
        android:visibility="visible" />

    <ImageButton
        android:id="@+id/switchCameraBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignTop="@+id/stopStream"
        android:layout_marginEnd="9dp"
        android:background="@color/transparent"
        android:contentDescription="@string/send"
        android:visibility="gone" />

    <ImageButton
        android:id="@+id/switchBtn"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_alignParentEnd="true"
        android:layout_alignTop="@+id/switchCameraBtn"
        android:layout_marginEnd="9dp"
        android:background="@drawable/call_btn"
        android:contentDescription="@string/send" />

    <RelativeLayout
        android:id="@+id/drawable_mod"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:gravity="center"
        android:orientation="horizontal"
        android:visibility="gone">

        <ImageView
            android:id="@+id/drawing1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_centerInParent="true"
            android:scaleType="fitXY"
            android:contentDescription="@string/drawing_one" />

    </RelativeLayout>

</RelativeLayout>

Answer 1

尝试使用 src 将图标设置为 ImageButton，例如

<ImageButton
        android:id="@+id/stopStream"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:src="@drawable/cancel_btn"
        android:background="@null"
        android:contentDescription="@string/stop_stream"
        android:onClick="hangup"
        android:visibility="visible" />

//used background="@null" to set the image button background as null to only show the icon which was set with the src.