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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 than 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 JitPack repository to your build.gradle:

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'com.github.badoo:android-weak-handler:1.3'
}

Use WeakHandler as you normally would use Handler

import com.badoo.mobile.util.WeakHandler;

public class ExampleActivity extends Activity {

    private WeakHandler handler; // We still need at least one hard reference to WeakHandler

    protected void onCreate(Bundle savedInstanceState) {
        handler = new WeakHandler();
        ...
    }

    private void onClick(View view) {
        handler.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.

Blog

Read more on our tech blog or explore our other open source projects