Can one relative layout / linear layout can have multiple constraint layouts? Do they affect on the performance of application while inflating?
Also, can one constraint Layout can have multiple constraint layouts?
If you are talking about nesting view groups(relative layout/linear layout/constraint layout) inside another view group, yes it is possible. But the issue with nesting view groups is each of the view group has to perform calculations to constrain its children. This is usually done in a depth-first search manner. So it will affect the inflation speed and thus the overall performance of the layout.
It is always better to keep the hierarchy as flat as possible. Which means maximum avoid the nesting of view groups wherever possible.
Nested view hierarchies should be avoided because it takes more time in rendering. To overcome from box-model logic (in HTML), ConstraintLayout has been introduced. It is clearly mentioned in the documentation.
Related
I have a list of items and I'm using RecyclerView to showing it.
This is an example of my list:
I need to understand what is better to use for item layout: RelativeLayout or ConstraintLayout in my case.
On the one hand, the RelativeLayout is considered as deprecated and recommended to use ConstraintLayout. But at the same time, it is better to use the ConstraintLayout when there are many child views, and then we will get a performance improvement. But I only have two child views and I have a feeling that the ConstraintLayout can only hurt.
Please tell me which view group is better to choose in my case?
Use Constraint Layout Only. Because Relative Layout is deprecated and now days most of the people not using.The Relative layout also fluctuates depending on screen.The
Constraint layout remains fix in all screen resolution.
I can see that Google actively promotes ConstraintLayout.
Is this means that it should be used in any case where this is possible?
I mean, if we have even some simple view with one or two child views, should we still use ConstraintLayout or this is not justifiable for simple views?
I mean from the performance perspective.
Are there any restrictions where usage is forbidden?
Performance suffers when you have multiple nested views eg relative layout contains a linear layout which contains a scroll view etc etc
The nature of constraint layout is that you can achieve things possible only by nesting other views, in a single constraint layout without nesting.
As long as the simple layout does not contain nested views, there is no strong performance gain by using constraint layout.
According to #Vardaan performances improvement is seen in the application which is also given in android developer blog and using it eliminates deep nesting, but it’s way too hard to do complex layouts with it since we don't deal with simple layout now days check this
I've created a very big layout (approx 2000 lines) that contains a large number of views and sub-layouts, often with weighted measures. The tree is pretty complex and goes down to 8 or more levels of nesting.
To create different "perspectives", the app programmatically sets some of the views' visibility to View.GONE, expecially those one that are at the head of a tree of views that I don't want to be displayed, in different moments of the app life cycle, and sometimes changes the weights to resize views; hence, the final layout that is displayed to the user contains at every time not more than 1/3 of the views and view-trees that are in the main layout.
I don't care about the performance at "switch" time, so when the user switches from one perspective to the other, I've got plenty of time to switch on and off the visibility and that's not a problem.
Instead, does having so many view and view trees set to View.GONE affect performance at runtime? What is the effect of GONE views on CPU and Memory performance, in contrast to a smaller layout (maybe programmatically inflated) where all views are displayed?
Actually while creating complex layout have to use constraint layout.
ConstraintLayout allows you to create large and complex layouts with a flat view hierarchy (no nested view groups). It's similar to RelativeLayout in that all views are laid out according to relationships between sibling views and the parent layout, but it's more flexible than RelativeLayout and easier to use with Android Studio's Layout Editor.
Please find the doc from url :
https://developer.android.com/training/constraint-layout/index.html
I'm writing an app with a custom theme and layout (some CI) for API 18+, so I need to align a lot of elements.
I read several times, that one should avoid nested layouts as good as possible, but also that some layout types are less efficient than others (RelativeLayout).
should I still avoid nested views these days?
if yes, what is more efficient
flat RelativeLayout
nested LinearLayout (2 levels)
what about TableLayout with TableRows
Currently I already have this layout hierarchy:
Drawer (for sidemenu)
Relative (because of header and footer)
Frame (Content goes below here, just used for easy replacing of fragments)
Your current layout hierarchy is very sample and under normal circumstances it should not be slow at all. Of course the FrameLayout is not needed as you are using a relative layout because your can align the center content below and above the header and footer of the relative layout children.
For this level of nesting the view there is absolutely no problem as for performance.
Both RealtiveLayout and LinearLayout extend FrameLayout with relative being a little heavier as it handles what else the relationships between the views.
If you need to align many element (like editexts and textview) in a form-type layout the best option is TableLayout.
General speaking layout inflation from XML is expensive, but nesting a view inside another makes no difference in real life. The problem would be if you had a thousand views in a TableView with TableRows having nested layout inside.
I got two views which are equally distributed on my main layout.But my two views in tern have nested childs which are again equally spaced.I am using nested layout weight's which is working fine. Whether nested weights effects the performance.What is the work around for this?
Every view — or worse, every layout manager — that you add to your
application comes at a cost: initialization, layout and drawing become
slower. The layout pass can be especially expensive when you nest
several LinearLayout that use the weight parameter, which requires the
child to be measured twice.
Refer: http://developer.android.com/resources/articles/layout-tricks-efficiency.html
You can use a RelativeLayout in most cases to avoid such expensive measurements. In a RelativeLayout, views are aligned with their parent, with the RelativeLayout itself, or with other views.
To clearly understand how the views are positioned with respect to each other, a wireframe of the layout can be captured by using HierarchyViewer perspective of Android SDK.