Selector, Layer-list and shape/bitmap in the same xml

Question

I have this code in an xml inside the drawable folder:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_pressed="true">
        <layer-list>
            <item>
                <shape android:shape="rectangle">
                    <size android:width="90dp" android:height="90dp" />

                <solid android:color="#9933CC" />
                </shape>
            </item>
            <item>
                <bitmap android:gravity="center" android:src="@drawable/main_achievements_synthesis" />
            </item>
        </layer-list>
    </item>
    <item>
        <layer-list>
            <item>
                <shape android:shape="rectangle">
                    <size android:width="90dp" android:height="90dp" />

                    <solid android:color="#AA66CC" />
                </shape>
            </item>
            <item>
                <bitmap android:gravity="center" android:src="@drawable/main_achievements_synthesis" />
            </item>
        </layer-list>
    </item>

</selector>

I use it to have an image with 2 states (to use as a button). Everything works as expected on emulator and devices.

I know that I can create different drawable xml and make a reference to achieve the same result.

I just switched to Android Studio and it shows me this mesage: Element XXX is not allowed here. It warns me about Layer-list and all the tags inside it. However, as I said, this code works just fine.

Should I switch my code into separated XMLs (knowing that I will only use them once) or is an "error" in the Android Studio's Inspector Code?

NOTE: I think my code can be optimized, but I haven't figured out how yet.

Answer 1

This is an error in Android Studio's linting tool. Please file a bug at https://code.google.com/p/android/issues/list.

Also, you can optimize a little by using:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <selector>
            <item android:state_pressed="true">
                <shape android:shape="rectangle">
                    <size android:width="90dp" android:height="90dp" />
                    <solid android:color="#9933CC" />
                </shape>
            </item>
            <item>
                <shape android:shape="rectangle">
                    <size android:width="90dp" android:height="90dp" />
                    <solid android:color="#AA66CC" />
                </shape>
            </item>
        </selector>
    </item>
    <item>
        <bitmap
            android:gravity="center"
            android:src="@drawable/main_achievements_synthesis" />
    </item>
</layer-list>