Question

I am writing a simple app that changes the application background randomly on button click.

I have a arraylist that contains 5 id’s of images that the application should use:

    ArrayList<Integer> imageID = new ArrayList<Integer>();
    imageID.add(R.drawable.frame_blue);
    imageID.add(R.drawable.frame_green);
    imageID.add(R.drawable.frame_lilac);
    imageID.add(R.drawable.frame_pink);
    imageID.add(R.drawable.frame_yellow);

I have two buttons in my layout xml file for next and previous. Both should change Application background when clicked.

I change the image background from this arraylist:

iM.setBackgroundResource(imageID.get(r.nextInt(5)));

and my layout xml looks like:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/parentLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="76dp"
        android:onClick="previous"
        android:text="Previous" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_alignParentRight="true"
        android:onClick="next"
        android:text="Next" />

</RelativeLayout>

All works fine on button click’s, ImageView background change as I expect, but the problem is the background is not changing smoothly.

It hangs some time. May be the main ui thread will be block for 1 or 2 second and this look like application hangs.

Hangs mean: Some time button remain clicked for a few seconds.

I tried asynctask did not have success. Is there a way to make it change smoothly?

Answer 1

you need to use caching in order to save time and not inflate every time the images
like this : Drawable image_frame_green = getResources().getDrawable(
R.drawable.frame_green);