Tap spark

简单的小demo, 有一定的用处. 用于反馈用户的touch事件, 以告知用户操作有效(近来越来越觉得, 用户体验很重要)。
基本思路，创建UIImageView子类，添加+ (id)handTraceWithPostion:(CGPoint)pos inView:(UIView *)inView type:(int)type方法。

实现如下：

+ (id)handTraceWithPostion:(CGPoint)pos inView:(UIView *)inView type:(int)type{
    // 注意内存，一定要autorelese
    return [[[self alloc] initWithPostion:pos inView:inView type:type] autorelease];
}

- (id)initWithPostion:(CGPoint)pos inView:(UIView *)inView type:(int)type{
    if ((self = [super initWithFrame:CGRectMake(0, 0, kTraceSizeFrom.width, kTraceSizeFrom.height)])) {
        
        [self setImage:[UIImage imageNamed:[NSString stringWithFormat:@"star%i.png", type]]];
        [self setCenter:pos];
        [inView addSubview:self];
        
        // start action
        // 另，注意内存，一定在动画结束后removeFromSuperview，以抵消被addSubview时被retain的一次，不然内存泄露，这个量可就太巨大了……
        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDidStopSelector:@selector(removeFromSuperview)];
        [UIView setAnimationDuration:kTraceDurTime];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        
        [self setFrame:CGRectMake(pos.x - kTraceSizeEnd.width / 2.0, pos.y - kTraceSizeEnd.height / 2.0, kTraceSizeEnd.width, kTraceSizeEnd.height)];
        [self setAlpha:0.0f];
        
        [UIView commitAnimations];
    }
    return self;
}

用法很明显，在相应的touch事件里调用类方法即可：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint pos = [touch locationInView:self.view];
    int type = arc4random() % 3 + 1;
    [HandTrace handTraceWithPostion:pos inView:self.view type:type];
}

效果如下：

工程：

Tagged with gesture