CODEWITHSUNDEEP
javaandroidxmlandroid-layoutuser-interface
Armai
Armai

Reputation: 174

Improving performance of instantiating and inflating views used with a ViewFlipper

I am using a ViewFlipper to display all the measurements the app has made (1 measurement = 1 page element). The problem is, the performance of initializing/reloading of the content of the ViewFlipper gets very bad if there are more then 50 elements. i.e., the app gets unresponsive for about 15 seconds after it has launched. I did some logging and found out, that more than 70% of the loading time is spent on View.inflate(ctx, R.layout.view_measurement, null);

From my understanding, inflate(...) does parse the layout xml file to a View so it can be used in Java. Since the layout xml file is everytime the same, it looks to me like there is the same heavy job being done for each element over and over again. I tried many things to change this and let this happen only one time, unfortunately without success. I also tried to use and tags in the xml also but always got errors.

I know that there are better ways rather than the ViewFlipper to do this job, but as I am in a hurry everything else works fine, I would like to keep this and find a fast solution.

MainActivity.java

...

ViewFlipper viewFlipper;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    viewFlipper = (ViewFlipper)super.findViewById(R.id.measurementsViewFlipper);

    int measurementsAmount = 100; //example

    for(i=0; i<measurementsAmount; i++){

        View measurementView = View.inflate(ctx, R.layout.view_measurement, null);

        ... fill the view ...

        viewFlipper.add(measurementView);

    }

    ...

}

view_measurement.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    android:gravity="center_vertical" 
    android:orientation="vertical">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:orientation="horizontal">


    ...


</LinearLayout>
</RelativeLayout>

Upvotes: 2

Views: 307

Answers (1)

user
user

Reputation: 87064

The only way to reduce the xml inflation time is to reduce the number of views used in the xml layout. For example, just by looking at he layout you posted, you could(and should) remove the root RelativeLayout if it's just wrapping the LinearLayout. Also, using ConstraintLayout might allow you further remove ViewGroups and reduce the nesting level and the view count.

But this will still not be ok because the real problem is you are inflating a lot of views upfront. In your example if the page layout contains just 5 views you'll create 500 views in total(100 x 5). That's a lot and this is why you need to have a view recycle mechanism so you don't need to create all views upfront, just a few for the current pages.

If you want ViewFlipper's behavior, the Android SDK has a component called AdapterViewFlipper which you should use instead. It just needs an additional adapter class, to which you'll pass the measurement data and in which you'll inflate the measurement layout.

Upvotes: 1

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