Im versucht, mein Hintergrundbild in der Listenansicht unscharf zu machen, aber ich habe versucht, den Tutorials zu folgen, und es funktioniert nicht. Jeder bitte beraten, danke.

main activity.java

public class IngredientCategoryMain extends Activity {

ListView list;
String[] title;
CategoryImageAdapter adapter;





@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_ingredient_category_main);

    list=(ListView)findViewById(R.id.listView);
    title = getResources().getStringArray(R.array.titles);
    adapter=new CategoryImageAdapter(this, mStrings, title);
    list.setAdapter(adapter);

}

@Override
public void onDestroy() {
    list.setAdapter(null);
    super.onDestroy();
}

public View.OnClickListener listener=new View.OnClickListener() {
    @Override
    public void onClick(View arg0) {
        adapter.imageLoader.clearCache();
        adapter.notifyDataSetChanged();


    }
};

public void onItemClick(int mPosition) {
    String tempValues = title[mPosition];
    Toast.makeText(IngredientCategoryMain.this, "Click on image "+tempValues+" to enter", Toast.LENGTH_LONG).show();

}

private String[] mStrings={
        "https://pixabay.com/static/uploads/photo/2014/07/08/14/33/breads-387544_960_720.jpg",
        "http://mtbev.org/wp-content/uploads/2014/02/Bottles.jpg",
        "https://c2.staticflickr.com/8/7023/6548962149_7a9fdd9cf4_b.jpg",
        "https://upload.wikimedia.org/wikipedia/commons/2/2f/Culinary_fruits_front_view.jpg",
        "https://upload.wikimedia.org/wikipedia/commons/e/ea/Indian_Spices.jpg",
        "https://pixabay.com/static/uploads/photo/2016/01/13/17/21/raw-1138562_960_720.jpg",
        "https://pixabay.com/static/uploads/photo/2010/12/13/09/51/seed-1716_960_720.jpg",
        "https://upload.wikimedia.org/wikipedia/commons/b/ba/Rice_grains_(IRRI).jpg",
        "http://www.stock-free.org/images/Thanksgiving-Stock-Free-Image-08112015-image-239.jpg",
        "https://pixabay.com/static/uploads/photo/2012/10/01/18/34/dips-58738_960_720.jpg",
        "https://pixabay.com/static/uploads/photo/2013/07/19/00/18/seafood-165220_960_720.jpg",
        "https://c1.staticflickr.com/3/2877/10866943666_471d9f2845_b.jpg"
};


}

xml-Datei, in der ich die Listenansicht erstellt habe

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content">


<ImageButton
    android:layout_width="90dp"
    android:layout_height="90dp"
    android:id="@+id/imageButton2"
    android:scaleType="fitXY"
    android:layout_below="@+id/textView2"
    android:layout_alignParentStart="true"
    android:layout_alignParentEnd="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:id="@+id/textView2"
    android:layout_marginLeft="20dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:textColor="#f7338b"
    android:textStyle="bold"
    android:background="#80ffffff" />

und listview.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.cassieleong.delishcart.IngredientCategoryMain"
tools:showIn="@layout/activity_ingredient_category_main"
android:background="#fde7e7">

<ListView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/listView"
    android:layout_alignParentTop="true"
    android:layout_alignParentStart="true"
    android:background="@drawable/appicon"/>