回收Imagebutton的可绘制对象

Question

In my 'homescreen' fragment I have a couple of Imagebuttons. XML for the Imagebutton is:

                <ImageButton
                    android:id="@+id/merkzettel"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center_horizontal"
                    android:background="#00000000"
                    android:scaleType="fitXY"
                    android:src="@drawable/dashboard_merkzettel_icon__selector" />

And the drawable XML selector looks like:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/icon_startseite_merkzettel_on"
          android:state_pressed="true" />
    <item android:drawable="@drawable/icon_startseite_merkzettel_off" />
</selector>

On an older device (Nexus S) when I flip the the device around for a while (changing screen orientation) I get the exception:

java.lang.OutOfMemoryError: bitmap size exceeds VM budget
    at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
    at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:460)
    at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:336)
    at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:697)
    at android.content.res.Resources.loadDrawable(Resources.java:1709)
    at android.content.res.Resources.getDrawable(Resources.java:581)
etcetc

This seems to be a common problem beause Android recreated the bitmap drawable every time the Activity / Fragment is recreated and for Drawables the recommended solution is to drawable.recycle() them in onDestroy() but I can't find a suitable method to get a hold on the drawable of the ImageButton.

Anyone knows a solution for this?

Answer 1

In manifest file's application tag add android:largeHeap = "true" then run your project.

Like Below

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.Light.NoTitleBar"
    android:largeHeap="true">
<application/>

In Destroy method

@Override
protected void onDestroy() {
    super.onDestroy();
    ((BitmapDrawable)imagebutton.getDrawable()).getBitmap.recycle();
}

and in onCreate method check this.

if (imagebutton.getDrawable() == null){
  // set your image button image here.
} else {
  // nothing to do.
}