Question

我有一个简单的应用程序向用户显示一个图像（在UIImageView中），它触摸屏幕的一部分，然后在下一个屏幕上显示相同的图像（在UIImageView中）但现在有一个“签名“重叠在上面。我遇到的问题是，似乎从触摸返回的x，y坐标似乎没有在第二个屏幕上的UIImageView上正确映射。

例如，当我触摸屏幕底部时，我得到：X：157.000000 Y：358.000000

但是屏幕的底部应该是480？因为我的屏幕尺寸是：屏幕高度和宽度X：320.000000 Y：480.000000。这会导致签名放置在与用户预期不同的位置。

我使用以下代码来获取触摸坐标：

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

    NSLog(@"TOUCH HAPPENED");
    UITouch *touch = [touches anyObject];
    CGPoint touchCoordinates = [touch locationInView:self.view];
    NSLog(@"X: %f   Y: %f",touchCoordinates.x, touchCoordinates.y);

}

我使用以下代码将“签名”与我从触摸中获得的值放在一起：

CGRect screenRect = [[UIScreen mainScreen] bounds]; 
        UIGraphicsBeginImageContext(screenRect.size);


        [pageImage drawInRect:CGRectMake(0, 0, screenRect.size.width, screenRect.size.height)]; // this is the original image

        NSLog(@"SCREEN HEIGHT AND WIDTH  AT   X: %f   Y: %f",screenRect.size.width, screenRect.size.height);


        NSLog(@"PLACING IT AT TOUCH COORDINATES  X: %f   Y: %f",sigLocation.x, sigLocation.y);
        UIImage *shieldLogo = [UIImage imageNamed:@"shield_bw.gif"];
        [shieldLogo drawInRect:CGRectMake(sigLocation.x, sigLocation.y, shieldLogo.size.width/2, shieldLogo.size.height/2)];
        [theSignature drawAtPoint:CGPointMake(sigLocation.x+24.000000, sigLocation.y) withFont:[UIFont fontWithName:@"Arial" size:8.0]];
        [theSignature2 drawAtPoint:CGPointMake(sigLocation.x+24.000000, sigLocation.y+ 8.000000) withFont:[UIFont fontWithName:@"Arial" size:8.0]];

        UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        [image setImage:resultingImage];

Answer 1

问题可能在于用户正在触摸的观点。您可以尝试（如this link中所示）

UITouch * touch = [touches anyObject];
CGPoint pos = [touch locationInView: [UIApplication sharedApplication].keyWindow];
NSLog(@"Position of touch: %.3f, %.3f", pos.x, pos.y);

这应该给出相对于屏幕的触摸位置。

获取触摸坐标的严重问题

1 个答案: