iOS：UIView的transform属性以及拖拽view的实现

一,UIView的transform属性的使用

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutletUIImageView *imageV;

@end

@implementation ViewController

- (void)viewDidLoad {
    [superviewDidLoad];
}

- (IBAction)moveUp:(id)sender {
    //平移
    [UIView animateWithDuration:0.5animations:^{
        //使用Make,它是相对于最原始的位置做的形变.
        //self.imageV.transform = CGAffineTransformMakeTranslation(0, -100);
        //相对于上一次做形变.
        self.imageV.transform = CGAffineTransformTranslate(self.imageV.transform,0, -100);
    }];
}
- (IBAction)moveDown:(id)sender {
    //平移
    [UIView animateWithDuration:0.5animations:^{
        //使用Make,它是相对于最原始的位置做的形变.
        //self.imageV.transform = CGAffineTransformMakeTranslation(0, -100);
        //相对于上一次做形变.
        self.imageV.transform = CGAffineTransformTranslate(self.imageV.transform,0,100);
    }];
}

- (IBAction)rotation:(id)sender {
    
    [UIViewanimateWithDuration:0.5animations:^{
        
        //旋转(旋转的度数, 是一个弧度)
        //self.imageV.transform = CGAffineTransformMakeRotation(M_PI_4);
        
        self.imageV.transform = CGAffineTransformRotate(self.imageV.transform,M_PI_4); 
    }];  
}
- (IBAction)scale:(id)sender {
    [UIView animateWithDuration:0.5animations:^{ 
       //缩放
        //self.imageV.transform = CGAffineTransformMakeScale(0.5, 0.5);
        self.imageV.transform = CGAffineTransformScale(self.imageV.transform,0.8,0.8);
        
    }];  
}
@end

二,UIView的touch方法的简单使用,实现拖拽view的效果

#import "RedView.h"

@implementation RedView

//当开始触摸屏幕的时候调用
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"%s",__func__);
}

//触摸时开始移动时调用(移动时会持续调用)
//NSSet:无序
//NSArray:有序
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
     //NSLog(@"%s",__func__);
    //做UIView拖拽
    UITouch *touch = [touches anyObject];
    
    //求偏移量 = 手指当前点的X - 手指上一个点的X
    CGPoint curP = [touch locationInView:self];
    CGPoint preP = [touchpreviousLocationInView:self];
    NSLog(@"curP====%@",NSStringFromCGPoint(curP));
    NSLog(@"preP====%@",NSStringFromCGPoint(preP));
    
    CGFloat offsetX = curP.x - preP.x;
    CGFloat offsetY = curP.y - preP.y;
    
    //平移
    self.transform =CGAffineTransformTranslate(self.transform, offsetX, offsetY); 
}

//当手指离开屏幕时调用
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
     NSLog(@"%s",__func__);
}

//当发生系统事件时就会调用该方法(电话打入,自动关机)
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
     NSLog(@"%s",__func__);
}
@end