Question

使用手势放大和缩小View如何设置最大和最小界限

Answer 1

第一步：声明手势对象，并加入你想要作用的view上

// 放大缩小手势

UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc]

initWithTarget:self action:@selector(scale:)];

[pinchRecognizer setDelegate:self];

[self.view addGestureRecognizer:pinchRecognizer];

[pinchRecognizer release];

第二步：声明3个成员变量，lastScale用来保存上次放大或缩小的那个值，并赋初值为1，因为原大小时就是1.

CGFloat lastScale = 1.0f;

设置可允许放大或缩小的值.

CGFloat mixScale, maxScale;

第三步：实现scale方法，来获取当前scale的值，并设置view的缩放。

- (void)scale:(UIGestureRecogize *)gesure {

if([recognizer state] == UIGestureRecognizerStateBegan) //1 {
lastScale = self.scale; //2 }
float nowScale; //3 nowScale = (lastScale - 1) + recognizer.scale; //4 nowScale = MIN(nowScale,maxScale);//不大于缩放上限 //5 nowScale = MAX(nowScale,mixScale);//不低于缩放下限 //6
CGAffineTransform currentTransform = self.view.transform;

self.view.transform = CGAffineTransformScale(currentTransform, nowScale,nowScale);

}