使用復雜的觸摸和手勢
Apple有各種手勢識別器的Class，下面，將使用幾個手勢識別器，實現：輕按、輕掃、張合、旋轉（搖動暫不涉及）。每個手勢都將有一個彈出式窗口的反饋。
在ViewController.m文件中，
1-點擊事件
-(void)foundTap:(UITapGestureRecognizer *)recognizer{
UIAlertView* alert=[[UIAlertView alloc] initWithTitle:@"Hello" message:@"tapped" delegate:nil cancelButtonTitle:@"OK"otherButtonTitles:nil];
[alert show];
}
- (void)viewDidLoad
{
[super viewDidLoad];
UITapGestureRecognizer *tapRecognizer; //創建一個輕按手勢識別器
tapRecognizer=[[UITapGestureRecognizer alloc]initWithTarget:self
action:@selector(foundTap:)];
//初始化識別器，並使用函數指針（方法指針）觸發同時實現方法
tapRecognizer.numberOfTapsRequired=1; //輕按對象次數（1）觸發此行為
tapRecognizer.numberOfTouchesRequired=1; //要求響應的手指數
[self.view addGestureRecognizer:tapRecognizer]; //相應的對象添加控制器
}
仔細觀察實現的方法，均是按著以下步驟：新建一個控制器實例--實例初始化--將其添加到類對象--實現函數指針中的方法（@selector()）.
【若想獲得輕按或輕掃手勢坐標，可添加：
CGPoint location=[recognizer locationInView:<the view>
<the view>即為手勢識別器的視圖名；location有兩個參數x和y】
2-輕掃：
接下來，我們按著上述步驟實現輕掃:
函數指針指向的方法：
-(void)foundSwipe:(UISwipeGestureRecognizer *)recognizer{
UIAlertView* alert=[[UIAlertView alloc] initWithTitle:@"Hello" message:@"swiped" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}
還是viewDidLoad：
UISwipeGestureRecognizer *swipeRecognizer; //創建一個輕掃識別器
swipeRecognizer=[[UISwipeGestureRecognizer alloc]initWithTarget:self
action:@selector(foundSwipe:)];
//對象初始化 並有函數指針
swipeRecognizer.direction=
UISwipeGestureRecognizerDirectionRight|UISwipeGestureRecognizerDirectionLeft;
//手勢相應 向左或向右滑動
swipeRecognizer.numberOfTouchesRequired=1; //掃動對象次數
[self.view addGestureRecognizer:swipeRecognizer]; //向對象添加控制器
相應掃動方向時，有四個方向可供選擇：
UISwipeGestureRecognizerDirectionRight/Left/Up/Down；
3-張合：
將實現放大縮小
函數指針方法：
-(void)foundPinch:(UIPinchGestureRecognizer *)recognizer{ //注意此處的類
NSString *message;
double scale;
scale=recognizer.scale; //識別器的scale(刻度尺、尺度)
//可用scale結合openGLES的glScalef實現縮放
message=[[NSString alloc]initWithFormat:@"縮放：Scale:%1.2f,Velocity:%1.2f",recognizer.scale,recognizer.velocity];
UIAlertView* alert=[[UIAlertView alloc] initWithTitle:@"Hello" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}
ViewDidLoad中：
UIPinchGestureRecognizer *pinchReconizer; //新建一個張合識別器對象
pinchReconizer=[[UIPinchGestureRecognizer alloc]initWithTarget:self
action:@selector(foundPinch)];
//初始化對象
[self.view addGestureRecognizer:pinchReconizer]; //添加控制器
4-旋轉
首先Cocoa類使用弧度為單位，角度和弧度的轉換關系：
角度=弧度*180/Pi
函數指針指向的方法：
-(void)foundRotation:(UIRotationGestureRecognizer *)recognizer{
NSString *message;
double rotation;
rotation=recognizer.rotation; //返回一個控制器角度
//在openGLES中可使用rotation結合glRoatef實現旋轉
message=[[NSString alloc] initWithFormat:@"旋轉，Radians：%1.2f,Velocity:%1.2f",
recognizer.rotation,recognizer.velocity];
UIAlertView* alert=[[UIAlertView alloc] initWithTitle:@"Hello" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}
viewDidLoad如下:
UIRotationGestureRecognizer *rotationRecognizer; //新建旋轉手勢控制器對象
rotationRecognizer=[[UIRotationGestureRecognizer alloc]initWithTarget:self
action:@selector(foundRotation:)];
//初始化對象
[self.view addGestureRecognizer:rotationRecognizer]; //添加控制器
