UI Performance

Avoid slow rendering:

System draw app's screen after every 1000/60FPS = 16.7ms. If our app CANNOT complete logic in 16.7ms it will force system to drop frame which called a jank.
To avoid it we can: use Layout Inspector, profile GPU rendering, use ConstrainLayout to reduce nested layout, move onMeasure, onLayout to background thread, use match_parent.
Long-running task should run asynchronous outside UI thread.
Avoid nested RecyclerView, avoid call notifyDatasetChanged() in RV adapter with small update. Apply DiffUtil.Callback to calculate the diff between two lists to minimal number of updates.
Use RV Prefetch to reduce the cost of inflation in most case by doing the work ahead of time, while UI thread is idle.
RV onBindViewHolder() or ListView onBind() called on UI thread -> it should be very simple, and take much less than one millisecond for all but the most complex items, it should only get data from POJO and update ui.

Optimize layout hierachy to avoid nested LinearLayout that use layout_weight or nested RelativeLayout.
Reuse layout using <include> or <merge>. Use dynamic views with views rarely use. Use RecyclerView instead of the old ListView.
Apply ViewHolder design pattern for lists to reuse row item view instead of create new View object. This will avoid findViewById() overhead. (Number of row item views = number of rows inside screen + 2 (threshold) -> recycle row item views to reuse when scroll).
Use lint tool to check layouts.