iphone开发：使用NSTimer制作动画

我编写了下面的代码，使用NSTimer将图像从顶部移动到按钮。但是，当我运行它时，我不能单独使用图像。基本上，图像留下了痕迹。我想要的是让图像一帧一帧地移动。我错过了什么

-(void)printOut:(NSTimer*)timer1;
{

    image = [[UIImageView alloc] initWithFrame:CGRectMake(50, -50+m, 50, 50)];
    [image setImage:[UIImage imageNamed:[NSString stringWithFormat:@"image.png"]]];

    CGRect oldFrame = image.frame;
    image.frame = CGRectMake(oldFrame.origin.x+5, oldFrame.origin.y, oldFrame.size.width, oldFrame.size.height);

    [self.view addSubview:image];

    m++;
    if (m == 1000) {
        [timer1 invalidate];
    }

}

编辑：我不想使用动画。因为稍后我需要使用碰撞检测，并且不可能控制动画的坐标

这样做：

image.frame = (top frame here)

[UIView animateWithDuration:0.4 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ 
//change time duration according to requirement
// animate it to the bottom of view
image.frame = (bottom frame here)
} completion:^(BOOL finished){
// if you want to do something once the animation finishes, put it here
}];

这样做：

image.frame = (top frame here)

[UIView animateWithDuration:0.4 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ 
//change time duration according to requirement
// animate it to the bottom of view
image.frame = (bottom frame here)
} completion:^(BOOL finished){
// if you want to do something once the animation finishes, put it here
}];

---

您每次都在分配子视图并将其添加到self。何时删除ImageView以消失上一个ImageView。因此，请在分配之前尝试删除图像。像这样试试

-(void)printOut:(NSTimer*)timer1;
{
[image removeFromSuperview];
image = nil;
image = [[UIImageView alloc] initWithFrame:CGRectMake(50, -50+m, 50, 50)];
[image setImage:[UIImage imageNamed:[NSString stringWithFormat:@"image.png"]]];

CGRect oldFrame = image.frame;
image.frame = CGRectMake(oldFrame.origin.x+5, oldFrame.origin.y, oldFrame.size.width, oldFrame.size.height);

[self.view addSubview:image];

m++;
if (m == 1000) {
    [timer1 invalidate];
}
}

---

您每次都在分配子视图并将其添加到self。何时删除ImageView以消失上一个ImageView。因此，请在分配之前尝试删除图像。像这样试试

-(void)printOut:(NSTimer*)timer1;
{
[image removeFromSuperview];
image = nil;
image = [[UIImageView alloc] initWithFrame:CGRectMake(50, -50+m, 50, 50)];
[image setImage:[UIImage imageNamed:[NSString stringWithFormat:@"image.png"]]];

CGRect oldFrame = image.frame;
image.frame = CGRectMake(oldFrame.origin.x+5, oldFrame.origin.y, oldFrame.size.width, oldFrame.size.height);

[self.view addSubview:image];

m++;
if (m == 1000) {
    [timer1 invalidate];
}
}

---

我不能理解你的疑问，你能吗please@Rajneesh071嗯，当我运行这个代码时，图像从屏幕顶部出现并开始移动，但它不是逐帧发生的。我的意思是，当新帧出现时，前一帧不会消失。希望清楚：/UIImageView*image=[[UIImageView alloc]initWithFrame:CGRectMake（50，-50+m，50，50）]；[image setImage:[UIImage ImageName:[NSString stringWithFormat:@“image.png”]]；[self.view addSubview:image]；我不能理解你的疑问，你能吗please@Rajneesh071嗯，当我运行这个代码时，图像从屏幕顶部出现并开始移动，但它不是逐帧发生的。我的意思是，当新帧出现时，前一帧不会消失。希望清楚：/UIImageView*image=[[UIImageView alloc]initWithFrame:CGRectMake（50，-50+m，50，50）]；[image setImage:[UIImage ImageName:[NSString stringWithFormat:@“image.png”]]；[self.view addSubview:image]；我很抱歉，但问题是我不想使用动画。因为稍后我需要使用碰撞检测，并且不可能控制动画的坐标。哦，我很抱歉，但问题是我不想使用动画。因为稍后我需要使用碰撞检测，并且不可能控制动画的坐标。