@OnClick array with optional ids (ButterKnife)

Question

I have an activity that inflates a view when a web request finished. Some of the widgets of this view have to be attached to one onClick method, so I have:

@OnClick({R.id.bt1, R.id.bt2, R.id.inflated_bt1, R.id.inflated_bt2}) public void onClick(View view) {     // ... } 

As R.id.inflated_bt1 and R.id.inflated_bt2 don't exist when the app is created, it throws an exception suggesting to set an @Optional annotation.

Required view 'inflated_bt1' with ID XXXXXXXX for method 'onClick' was not found. If this view is optional add '@Optional' annotation.

Is there a way to set some of the views with the @Optional annotation and inject them when the view is inflated? Or, is there another way to do it?

Thank you

Answer 1

Just add @Optional annotation on the top of your method as is shown in the code below:

@Optional @OnClick({R.id.bt1, R.id.bt2, R.id.inflated_bt1, R.id.inflated_bt2}) public void onClick(View view) {     // ... } 

There is a case where you don't have R.id.inflated_bt1 in the layout xml which you use on your Activity. For case like this you have to use @Optional annotation.

When you use only @OnClick annotation in YourClass$$ViewInjector source code looks like below:

view = finder.findRequiredView(source, 2131230789, "method 'onClick'"); view.setOnClickListener(   new butterknife.internal.DebouncingOnClickListener() {     @Override public void doClick(       android.view.View p0     ) {       target.onClick();     }   }); 

and the method findRequiredView throws IllegalStateException when view is null.

But when you use additionally @Optional annotation, generated code looks like below

view = finder.findOptionalView(source, 2131230789); if (view != null) {   view.setOnClickListener(     new butterknife.internal.DebouncingOnClickListener() {       @Override public void doClick(         android.view.View p0       ) {         target.onClick();       }     }); } 

Answer 2

The correct answer is to use the @Nullable annotation. See the Butterknife home page. Usage example:

import android.support.annotation.Nullable;  @Nullable @OnClick(R.id.maybe_missing) void onMaybeMissingClicked() {     // TODO ... } 

EDIT:

In the year since I wrote this answer and it was accepted, the Butterknife docs changed, and the current preferred method for accomplishing this is to use the @Optional annotation. Since this is the accepted answer, I feel it important to update it to address current practice. For example:

import butterknife.Optional;  @Optional @OnClick(R.id.maybe_missing) void onMaybeMissingClicked() {     // TODO ... }