有没有办法在视图中反转触摸位置？

Question

我正在编写一个基于 CGRect 中的触摸位置更改图像和变量的方法。我目前正在使用一系列 if 语句手动反转触摸位置。我不相信这是一种特别有效的方法。

它适用于图像更改，但对于 var 更改（我还没有实现）我需要以 +1 为增量从 1 到 100 进行缩放。

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView: self.view];
    if (CGRectContainsPoint(CGRectMake(0, 20, 117, 200), point)) {

    if (point.y >= 20 && point.y <= 32) //12
        imageA.image = [UIImage imageNamed:@"ChemA-15.png"];
    if (point.y >= 33 && point.y <= 45)
        imageA.image = [UIImage imageNamed:@"ChemA-14.png"];
    if (point.y >= 46 && point.y <= 58)
        imageA.image = [UIImage imageNamed:@"ChemA-13.png"];
    if (point.y >= 59 && point.y <= 70)
        imageA.image = [UIImage imageNamed:@"ChemA-12.png"];
    if (point.y >= 71 && point.y <= 82)
        imageA.image = [UIImage imageNamed:@"ChemA-11.png"];
    if (point.y >= 83 && point.y <= 94)
       imageA.image = [UIImage imageNamed:@"ChemA-10.png"];
    if (point.y >= 95 && point.y <= 106)
        imageA.image = [UIImage imageNamed:@"ChemA-9.png"];
    if (point.y >= 107 && point.y <= 118)
        imageA.image = [UIImage imageNamed:@"ChemA-8.png"];
    if (point.y >= 119 && point.y <= 130)
        imageA.image = [UIImage imageNamed:@"ChemA-7.png"];
    if (point.y >= 131 && point.y <= 142)
        imageA.image = [UIImage imageNamed:@"ChemA-6.png"];
    if (point.y >= 143 && point.y <= 154)
        imageA.image = [UIImage imageNamed:@"ChemA-5.png"];
    if (point.y >= 155 && point.y <= 166)
        imageA.image = [UIImage imageNamed:@"ChemA-4.png"];
    if (point.y >= 167 && point.y <= 178)
       imageA.image = [UIImage imageNamed:@"ChemA-3.png"];
    if (point.y >= 179 && point.y <= 190)
        imageA.image = [UIImage imageNamed:@"ChemA-2.png"];
    if (point.y >= 191 && point.y <= 202)
        imageA.image = [UIImage imageNamed:@"ChemA-1.png"];

    }
}

有没有更好的方法来做到这一点？感谢您提供的任何帮助。

Answer 1

你可以计算出你需要什么样的图片：

int image = 15 - (int)((point.y - 20) / 13);

然后从中创建一个字符串并检查以下边界：

if(image >= 1 && image <= 15)
    imageA.image = [UIImage imageNamed:
                    [NSString stringWithFromat: @"ChemA-%d.png", image]];