利用AOP对点击事件作防抖处理

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.CLASS)
public @interface Except {
}

@Aspect
public class SingleClickAspect {
    ...
}

// normal onClick
private static final String ON_CLICK_POINTCUTS = "execution(* android.view.View.OnClickListener.onClick(..))";
// 如果 onClick 是写在 xml 里面的
private static final String ON_CLICK_IN_XML_POINTCUTS = "execution(* android.support.v7.app.AppCompatViewInflater.DeclaredOnClickListener.onClick(..))";
// butterknife on click
private static final String ON_CLICK_IN_BUTTER_KNIFE_POINTCUTS = "execution(@butterknife.OnClick * *(..))";
// view tag unique key, must be one of resource id
private static final int SINGLE_CLICK_KEY = R.string.me_yuqirong_singleclick_tag_key;

@Pointcut(ON_CLICK_POINTCUTS)
public void onClickPointcuts() {
}

@Pointcut(ON_CLICK_IN_XML_POINTCUTS)
public void onClickInXmlPointcuts() {
}

@Pointcut(ON_CLICK_IN_BUTTER_KNIFE_POINTCUTS)
public void onClickInButterKnifePointcuts() {
}

@Around("onClickPointcuts() || onClickInXmlPointcuts() || onClickInButterKnifePointcuts()")
public void throttleClick(ProceedingJoinPoint joinPoint) throws Throwable {
    try {
        // check for Except annotation
        Signature signature = joinPoint.getSignature();
        if (signature instanceof MethodSignature) {
            MethodSignature methodSignature = (MethodSignature) signature;
            Method method = methodSignature.getMethod();
            // 如果有 Except 注解，就不需要做点击防抖处理
            boolean isExcept = method != null && method.isAnnotationPresent(Except.class);
            if (isExcept) {
                Log.d(TAG, "the click method is except, so proceed it");
                joinPoint.proceed();
                return;
            }
        }
        Object[] args = joinPoint.getArgs();
        View view = getViewFromArgs(args);
        // unknown click type, so skip it
        if (view == null) {
            Log.d(TAG, "unknown type method, so proceed it");
            joinPoint.proceed();
            return;
        }
        Long lastClickTime = (Long) view.getTag(SINGLE_CLICK_KEY);
        // if lastClickTime is null, means click first time
        if (lastClickTime == null) {
            Log.d(TAG, "the click event is first time, so proceed it");
            view.setTag(SINGLE_CLICK_KEY, SystemClock.elapsedRealtime());
            joinPoint.proceed();
            return;
        }
        if (canClick(lastClickTime)) {
            Log.d(TAG, "the click event time interval is legal, so proceed it");
            view.setTag(SINGLE_CLICK_KEY, SystemClock.elapsedRealtime());
            joinPoint.proceed();
            return;
        }
        Log.d(TAG, "throttle the click event, view id = " + view.getId());
    } catch (Throwable e) {
        e.printStackTrace();
        Log.d(TAG, e.getMessage());
        joinPoint.proceed();
    }
}

/**
 * 获取 view 参数
 *
 * @param args
 * @return
 */
private View getViewFromArgs(Object[] args) {
    if (args != null && args.length > 0) {
        Object arg = args[0];
        if (arg instanceof View) {
            return (View) arg;
        }
    }
    return null;
}

/**
 * 判断是否达到可以点击的时间间隔，这里间隔就设置为500L
 *
 * @param lastClickTime
 * @return
 */
private boolean canClick(long lastClickTime) {
    return SystemClock.elapsedRealtime() - lastClickTime
            >= 500L;
}