Remove "Method is never used" warning for OnClick annotation in Android Studio

Question

Sorry if this question has been asked before. I am using the Butterknife 5.0 with the latest version of Android Studio(0.5.7). How can I remove the "Method is never used" warning for methods that use the 'OnClick' Annotation of ButterKnife.I noticed that Eclipse doesnt give this warning for the 'OnClick' methods. Thanks in advance

Answer 1

The correct way in Android Studio to suppress these warnings is to press Alt+Enter on the method giving the Method 'yourFunction()' is never used warning, and selecting

Suppress for methods annotated by 'butterknife.OnClick'

Answer 2

Simply add this annotation:

@SuppressWarnings("unused")

Just like that:

@SuppressWarnings("unused")
@OnClick(R.id.myButton)
public void clickHandler()
{
    // ...
}

My personal preference (which I see as good practice) is to add a comment with a brief explanation:

@SuppressWarnings("unused") // it's actually used, just injected by Butter Knife

Answer 3

Osvald's answer is spot on.

However, if you want to avoid suppressing warnings separately for each type of butterknife annotation, follow his instructions, and then open up .idea/misc.xml and find this section:

<component name="EntryPointsManager">
  <entry_points version="2.0" />
  <list size="1">
    <item index="0" class="java.lang.String" itemvalue="butterknife.OnClick" />
  </list>
</component>

Therein, simply replace butterknife.OnClick with butterknife.*.

From now on, all your injected event handlers will evade the warning.

Answer 4

Add another dependency for the compiler:

Gradle

dependencies {
    annotationProcessor 'com.jakewharton:butterknife-compiler:8.4.0' // new line
    compile 'com.jakewharton:butterknife:8.4.0' // original library
}

This is recommended on the official website.

Remember to Build -> Rebuild Project, so it will generate usages and make the warning go away.

Answer 5

With Kotlin, you should use @Suppress("unused") instead of @SuppressWarnings("unused")

@Suppress("unused") 
fun foo() {

}