Proper Android Activity Cleanup to Reduce Memory Footprint

Question

Perhaps this question is two-fold:

The goal is to reduce memory footprint of the Android app and allow for a reasonably usable experience on low end Low/Med DPI devices with 512 MB ram or less (legacy/repaid phones/etc.)

What I'm observing is that after navigating a few Activities performance degrades, assuming due to created Activities being cached.

What's the preferred way to clean up in between Activity navigation aiming to reduce memory footprint?

Answer 1

You wrote

What's the preferred way to clean up in between Activity navigation aiming to reduce memory footprint?

You can clear the Activity stack by doing the following when starting a new Activity:

Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

This will close all activities except NextActivity.

Alernatively you can specify it in your Manifest that the Activity should not 'live on' when you start another Activity:

<activity
  android:name=".CurrentActivity"
  //...
  android:noHistory="true"/>

You also need to make sure the closed Activities are not leaked, e.g. you need to unregister all BroadcastReceivers which were registered in your Activity when you call onPause() or onStop().

The details will ultimately depend on the specifics of your app.