A JUnit Rule for capturing screenshots using Spoon

CaptureScreenshots.java

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Target(METHOD)
@Retention(RUNTIME)
public @interface CaptureScreenshots {
  String before() default "";
  String after() default "";
}

ScreenshotsRule.java

import android.app.Activity;
import android.support.test.rule.ActivityTestRule;
import android.text.TextUtils;

import com.squareup.spoon.Spoon;

import org.junit.runner.Description;
import org.junit.runners.model.Statement;

public class ScreenshotsRule<T extends Activity> extends ActivityTestRule<T> {
  private Description description;

  public ScreenshotsRule(Class<T> clazz) {
    super(clazz);
  }

  @Override
  public Statement apply(Statement base, Description description) {
    this.description = description;
    return super.apply(base, description);
  }

  @Override
  public void finishActivity() {
    if (getActivity() != null) {
      beforeActivityFinished();
    }
    super.finishActivity();
  }

  public void screenshot(String tag) {
    if (getActivity() == null) {
      throw new IllegalStateException("Activity has not been started yet" +
              " or has already been killed!");
    }

    Spoon.screenshot(getActivity(), tag, description.getClassName(),
            description.getMethodName());
  }

  Override
  protected void afterActivityLaunched() {
    CaptureScreenshots captureScreenshots =
            description.getAnnotation(CaptureScreenshots.class);
    if (captureScreenshots != null) {
      String tag = captureScreenshots.before();
      if (TextUtils.isEmpty(tag)) {
        tag = "before_" + description.getMethodName();
      }
      screenshot(tag);
    }
  }

  protected void beforeActivityFinished() {
    CaptureScreenshots captureScreenshots =
            description.getAnnotation(CaptureScreenshots.class);
    if (captureScreenshots != null) {
      String tag = captureScreenshots.after();
      if (TextUtils.isEmpty(tag)) {
        tag = "after_" + description.getMethodName();
      }
      screenshot(tag);
    }
  }
}