Question

当我触摸UIImage它移动到一个随机位置时，我正试图这样做，但是在两次或多次移动后它会一直离开屏幕。我试图重置它是因为它移动到一个随机点但它仍然最终离开屏幕。那么有没有办法告诉它是否会关闭屏幕或我只是遗漏了什么？

-(IBAction)moveimage {
    int x = 240;
    int y = 160;

    image.center = CGPointMake(x, y);

    int xr = arc4random() % (int) self.view.frame.size.width;
    int yr = arc4random() % (int) self.view.frame.size.height;

    image.center = CGPointMake(xr, yr);

}

我还是iOS的新手，所以感谢任何帮助，谢谢。

Answer 1

小心你的xr和yr类型。 CGPoint是2 CGFloat的结构（即在64位架构上加倍）。

Answer 2

int xr = arc4random() % (int) self.view.frame.size.width;

int yr = arc4random() % (int) self.view.frame.size.height;

xr = MAX(image.frame.size.width , xr); // left edge detect
xr = MIN(image.superview.frame.size.width - image.frame.size.width , xr); //right edge detect

yr = MAX(image.frame.size.height , yr); //  top edge detect
yr = MIN(image.superview.frame.size.height - image.frame.size.height , yr); //bottom edge detect 

image.center = CGPointMake(xr, yr);

Answer 3

尝试使用以下代码替换您的代码：

CGFloat xRange = self.view.bounds.size.width - image.bounds.size.width;
CGFloat yRange = self.view.bounds.size.height - image.bounds.size.height;

CGFloat minX = self.view.center.x - (xRange / 2);
CGFloat minY = self.view.center.y - (yRange / 2);

int randomX = (arc4random() % (int)floorf(xRange)) + minX;
int randomY = (arc4random() % (int)floorf(yRange)) + minY;
image.center = CGPointMake(randomX, randomY);

此外，当您运行以下内容时，只需记下原始代码：

int x = 240;

int y = 160;

image.center = CGPointMake(x, y);

直接跟着这个：

int xr = arc4random() % (int) self.view.frame.size.width;

int yr = arc4random() % (int) self.view.frame.size.height;

image.center = CGPointMake(xr, yr);

您的第一个作业变得不必要

Answer 4

试试这个

-(IBAction)moveimage {

    int x = 240;
    int y = 160;

    image.center = CGPointMake(x, y);

    int newx =[self getRandomNumberBetween:self.view.bounds.size.width-imageWidth
                                 maxNumber:self.view.bounds.size.height-imageHeight];
    int newy =[self getRandomNumberBetween:self.view.bounds.size.width-imageWidth
                                 maxNumber:self.view.bounds.size.height-imageHeight];

    CGRect newFrame=[image frame];
    newFrame.origin.x = newx;
    newFrame.origin.y = newy;

    [image setFrame:newFrame];
}

- (NSInteger)getRandomNumberBetween:(NSInteger)min
                          maxNumber:(NSInteger)max{
    return min + arc4random() % (max - min + 1);
}

如何阻止图像离开屏幕？

4 个答案: