Custom DialogPreference not showing ImageView properly

Question

I have a custom DialogPreference:

    <com.myapp.MyPreferenceDialog
        android:key="dialog_key"
        android:title="Test MyDialogPreference"
        android:positiveButtonText="ok"
        android:negativeButtonText="cancel"
        />

The dialog code is the following:

class MyDialogPreference extends DialogPreference
{

    public MyDialogPreference( Context context, AttributeSet attrs )
    {
        super(context, attrs);
        setDialogLayoutResource( R.layout.test );
    }
}

The layout xml code is the following:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical">

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/image" />
</LinearLayout>

When i launch the app settings and touch "Test MyDialogPreference", a dialog is shown but the imageview does not display any image. I know how to fix this programmatically (just override onBindDialogView() and set the ImageView image resource to its drawable), but i would like to understand why i have to do it programmatically.

Answer 1

add following to your build.gradle file

defaultConfig {  
 vectorDrawables.useSupportLibrary = true  
}