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View inflation you can intercept.

ViewPump installs a custom LayoutInflater via a ContextThemeWrapper and provides an API of pre/post-inflation interceptors.

Getting started


Include the dependency Download (.aar) :

dependencies {
    implementation 'io.github.inflationx:viewpump:2.1.0'


Define your interceptor. Below is a somewhat arbitrary example of a post-inflation interceptor that prefixes the text in a TextView.

public class TextUpdatingInterceptor implements Interceptor {
    public InflateResult intercept(Chain chain) {
        InflateResult result = chain.proceed(chain.request());
        if (result.view() instanceof TextView) {
            // Do something to result.view()
            // You have access to result.context() and result.attrs()
            TextView textView = (TextView) result.view();
            textView.setText("[Prefix] " + textView.getText());
        return result;

Below is an example of a pre-inflation interceptor that returns a CustomTextView when a TextView was defined in the layout's XML.

public class CustomTextViewInterceptor implements Interceptor {
    public InflateResult intercept(Chain chain) {
        InflateRequest request = chain.request();
        if ("TextView")) {
            CustomTextView view = new CustomTextView(request.context(), request.attrs());
            return InflateResult.builder()
        } else {
            return chain.proceed(request);


Create a ViewPump instance via ViewPump.builder() and add your interceptors. The order of the interceptors is important since they form the interceptor chain of requests and results.

An interceptor may choose to return a programmatically instantiated view rather than letting the default inflation occur, in which case interceptors added after it will be skipped. For this reason, it is better to add your post-inflation interceptors before the pre-inflation interceptors

ViewPump viewPump = ViewPump.builder()
    .addInterceptor(new TextUpdatingInterceptor())
    .addInterceptor(new CustomTextViewInterceptor())

Once the instance is created (via dependency injection or otherwise), provide it to your relevant context via wrapping the Activity context:

protected void attachBaseContext(Context newBase) {
    super.attachBaseContext(ViewPumpContextWrapper.wrap(newBase, viewPump));

You're good to go!

To see more ideas for potential use cases, check out the Recipes wiki page.


If you need to test views in isolation (i.e. not under the indirect umbrella of an Activity), you need to set factory2 manually in order for ViewPump to work.

val context = ViewPumpContextWrapper.wrap(textContext, viewPump)
LayoutInflater.from(context).factory2 = FakeFactory2() // Can be a stub that just returns null

// Now inflate your view
val view = LayoutInflater.from(context).inflate(R.layout.view, null)

Otherwise, no factory2 instance will be set in the underlying LayoutInflater and subsequently ViewPump will never be called during inflation.



Copyright 2017 InflationX

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