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

Temperance

https://mcmap.net/q/353648/-how-to-avoid-complier-warning-parameter-39-x-39-is-never-used - kind of same – Cichlid

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'

Kruger

how do you undo this action? – Bazaar

FYI, it adds exactly what @codesparkle said (tested with AS 2.0) – Jennine

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

Flighty

it can be more detailed: @SuppressWarnings({"UnusedDeclaration"}) @SuppressWarnings({"UnusedParameters"}) – Purington

@SuppressWarnings("unused") did not work for me, but @Suppress("unused") did. – Acerbity

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.

Misericord

Not bad, but I think one doesn't usually commit .idea files into the repository, so every developer has to do this trick individually, whereas an annotation works automatically for everyone since it's an integral part of the codebase – Flighty

@KonradMorawski Both methods only change .idea files so you'd have the same issue either way. What is and is not committed to a repository depends entirely on what the repository is configured to ignore. – Meatman

@Meatman no, SuppressWarnings is an annotation used in code files directly – Flighty

Oh I see, I was referring to Osvald's and Codesparkle's answers, which only change .idea/misc.xml file. You meant annotations. I'll just shuffle over here... – Meatman

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.

Chic

Answer 5

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

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

}

Acerbity