Even though android is powerful mobile operating system platform still there are few pitfalls. One of them is memory optimization to ensure user never run out of space and do you know how to do it.

1. Android Memory Optimization
Best Practices for Better
Memory Management

2. Two types of memories in Android
Clean RAM
Android makes memory available to the system through paging and memory-
mapping techniques which is clean RAM. Files and resources are kept in
mapped pages which can be easily recovered from disk hence these can be
paged out and memory can be released for the system.
Dirty RAM
Dirty RAM is one that is quite expensive when runs in background since they
cannot be paged out. Maximum memory inside a running application is dirty
memory and it is used for memory optimization.

3. Android Memory Overview
All applications are recognized by android either as running process or
cached process. Android kills one or multiple cached processes when
there is need of memory for running process. According to LRU (least
recently used) process under cached process are killed.

4. Memory Optimization: Best practices for
enhanced memory usage
When the system is not running out of memory then it is good for
boosting the overall memory usage and performance of Android and
eventually ensure a delightful user experience.

5. Avoid Memory Leaks at all cost
✓ Main reason for memory leak is to forget to free up the allocated memory
before all related references go out of the scope. Memory leaks happen
when references to the objects that are no longer needed in an app are
not released and this type of memory leaks are known as logical memory
leaks.
✓ A very strong Logical memory leaks is the result of not releasing references
to those objects that are no more required in app. When a strong
reference to an object is still present then even the garbage collector fails
to remove the object from the memory

6. Avoid Memory Leaks at all cost

7. Avoid Memory Leaks at all cost
It can be avoided by following ways:
✓ Once the database query is done always close the cursor.
✓ Remember to call unregisterReceiver() after calling
registerReceiver().
✓ Significant memory loss is caused by Activity instance leakage and
it also increases the OOM(out of memory) value.
This can be avoided as following:
✓ Don’t keep the long-lived references to a context-activity.
✓ Replace the context-activity with context-application.
✓ Use AsyncTask for short-lived operations.

8. Profile guided Dex file layout

9. Profile guided Dex file layout
Application is wrapped in an APK file where multiple dex files
(contains instruction for application execution) are present and when
an application is launched on the device, the dex file is read by device
into memory with several hundred pages being loaded into the
memory. Usually, developers are not aware about important use
cases required by a specific user hence, there are all a lot of
unimportant things present along with important things.

10. Profile guided Dex file layout
To improve the Dex file layout use the JIT profile information for moving important things
close to each other as shown below:

11. Profile guided Dex file layout
Below snapshot showcase a significant reduction in RAM usage by dex file after
layout.

12. Code Sinking
In this type of optimization instructions are moved closer to those instructions
that actually use them. Instructions that are rarely used need to be moved
closer to where they are used. It basically means instruction not in the regular
flow should be moved to the exceptional cases.

13. Code Sinking

14. It is a common optimization technique in object oriented language a runtime
will try to infer classes and methods that can be made final even though they
aren't final actually. Having this information internally gives a lot of room for
the compiler for more optimizations.
Class Hierarchy Analysis

15. Class Hierarchy Analysis

16. Loop Optimization
Programs tend to spend most of the time inside loops. Loop optimization has an analysis part
where we look into the program and transformations are performed in the optimization part.

17. Optimized Data Containers
Few classes provided are not optimized for usage on mobile devices.
Implementation of generic HashMap is a bit memory intensive due to its
requirement for a separate entry object in each mapping. This memory issue
can be solved by using optimized data containers like SparseArray,
SparseBooleanArray, and LongSparseArray. As SparseArray classes avoid the
system requirement to autobox the key and sometimes the value thus, they are
more efficient. When required switch to raw arrays for lean data structure.

18. Choose Data Types Wisely
Using primitive types will reduce the memory usage. An integer objects
consume 4 times more memory than a primitive int. Similarly, a boolean object
will occupy more memory than a primitive boolean type. For Constants prefer
static final variables as they consume half the memory in comparison to enums.