RelativeLayout doesn't draw children if background is set

问题

I have class CalloutView extended from RelativeLayout. Currently has no any methods, it just redefines constructors.

I also have an XML layout for it:

<?xml version="1.0" encoding="utf-8"?>
<com.example.CalloutView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="70dp">

    <ImageButton
        android:id="@+id/imageButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="6dp"
        android:layout_marginTop="6dp"
        android:background="@drawable/button_disclose"
        android:src="@drawable/disclose" />

</com.example.CalloutView>

I inflate layout of instance of CalloutView by this code:

this.calloutView = (CalloutView) ((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.callout_view, null);
this.calloutView.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, 105));
this.calloutView.measure(MeasureSpec.makeMeasureSpec(400, MeasureSpec.AT_MOST),  MeasureSpec.makeMeasureSpec(105, MeasureSpec.EXACTLY));

It renders perfectly. ImageButton appears on the right side of it like it should.

But when I add a background to CalloutView:

<com.example.CalloutView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="70dp"
    android:background="@drawable/callout">
...
</com.example.CalloutView>

It renders only background, but ImageButton doesn't appear.

Edit

I use NinePatch image as a background. If I replace it with non-NinePatch everything works fine. Bug in Android?

The main question is, why it ImageButton isn't rendered, if background is set?

回答1:

I tried your code but replaced your custom layout with a RelativeLayout:

RelativeLayout calloutView = (RelativeLayout) ((LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.main, null);
        calloutView.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, 105));
        calloutView.measure(MeasureSpec.makeMeasureSpec(400, MeasureSpec.AT_MOST),  MeasureSpec.makeMeasureSpec(105, MeasureSpec.EXACTLY));

        setContentView(calloutView);

And the xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="70dp"
    android:background="@drawable/ic_launcher">

    <ImageButton
        android:id="@+id/imageButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="6dp"
        android:layout_marginTop="6dp"
        android:background="#ff0000"
        android:src="@drawable/ic_launcher"
         />

</RelativeLayout>

It works fine:

Therefore, this must be something about your layout. Make sure that in your redefined constructors, your call the super constructors first.

回答2:

It looks like a bug in Android 2.3.3. I use my PNG file as NinePatch as background, I get this issue. If I use another NinePatch, everything works like it should.

I can't reproduce this issue on Android 3.1.

来源：https://stackoverflow.com/questions/8184961/relativelayout-doesnt-draw-children-if-background-is-set

标签

android

background

relativelayout

imagebutton

xml-layout