Android Weak Handler

Memory safer implementation of android.os.Handler

Problem

Original implementation of Handler always keeps hard reference to handler in queue of execution. Any object in Message or Runnable posted to android.os.Handler will be hard referenced for some time. If you create anonymous Runnable and call to postDelayed with large timeout, that Runnable will be held in memory until timeout passes. Even if your Runnable seems small, it indirectly references owner class, which is usually something as big as Activity or Fragment.

You can read more on our blog post.

Solution

WeakHandler is trickier then android.os.Handler , it will keep WeakReferences to runnables and messages, and GC could collect them once WeakHandler instance is not referenced any more.

Usage

Add reference to your build.gradle:

repositories {
    maven {
        repositories {
            url 'https://oss.sonatype.org/content/repositories/releases/'
        }
    }
}

dependencies {
    compile 'com.badoo.mobile:android-weak-handler:1.1'
}

Use WeakHandler as you normally would use Handler

import com.badoo.mobile.util.WeakHandler;

public class ExampleActivity extends Activity {

    private WeakHandler mHandler; // We still need at least one hard reference to WeakHandler
    
    protected void onCreate(Bundle savedInstanceState) {
        mHandler = new WeakHandler();
        ...
    }
    
    private void onClick(View view) {
        mHandler.postDelayed(new Runnable() {
            view.setVisibility(View.INVISIBLE);
        }, 5000);
    }
}

Credits

Weak Handler is brought to you by Badoo Trading Limited and it is released under the MIT License.

Created by Dmytro Voronkevych