抽屉效果使用.md

当一个控制器的View添加到另一个控制器的View上的时候,那此时View所在的控制器也应该成为上一个控制器的子控制器.

#import <UIKit/UIKit.h>

@interface DragerViewController : UIViewController
@property (nonatomic, weak, readonly)  UIView *leftV;
@property (nonatomic, weak, readonly)  UIView *rightV;
@property (nonatomic, weak, readonly)  UIView *mainV;
@end

#import "DragerViewController.h"
#import <objc/message.h>

#define screenW [UIScreen mainScreen].bounds.size.width

@interface DragerViewController ()
@end

@implementation DragerViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    //添加子控件
    [self setUp];
    
    
    //添加手势
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    
    [self.mainV addGestureRecognizer:pan];
    
    
    //给控制器的View添加点按手势
//    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap)];
//    [self.view addGestureRecognizer:tap];
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:sel_registerName("tap")];
    //在设置里要修改msg设置，不然无法编译通过
    objc_msgSend(self.view, sel_registerName("addGestureRecognizer:"),tap);
}

- (void)tap{
    //让MainV复位
    CGFloat targetX = 0;
    [self animationWithOffsetX:targetX];
}



#define targetR 275
#define targetL -275
- (void)pan:(UIPanGestureRecognizer *)pan{
    
    //获取偏移量
    CGPoint transP = [pan  translationInView:self.mainV];
    //为什么不使用transform,是因为我们还要去修改高度,使用transform,只能修改,x,y
    //self.mainV.transform = CGAffineTransformTranslate(self.mainV.transform, transP.x, 0);

    self.mainV.frame = [self frameWithOffsetX:transP.x];
    //判断拖动的方向
    if(self.mainV.frame.origin.x > 0){
        //向右
        self.rightV.hidden = YES;
    }else if(self.mainV.frame.origin.x < 0){
        //向左
        self.rightV.hidden = NO;
    }
    
    //当手指松开时,做自动定位.
    CGFloat targetX = 0;
    if (pan.state == UIGestureRecognizerStateEnded) {
        if (self.mainV.frame.origin.x > screenW * 0.5 ) {
            //1判断在右侧
            //当前View的x有没有大于屏幕宽度的一半,大于就是在右侧
            targetX = targetR;
        }else if(CGRectGetMaxX(self.mainV.frame) < screenW * 0.5){
            //2.判断在左侧
            //当前View的最大的x有没有小于屏幕宽度的一半,小于就是在左侧
            targetX = targetL;
        }
       
        [self animationWithOffsetX:targetX];
    }
    //复位
    [pan setTranslation:CGPointZero inView:self.mainV];
    
}

- (void)animationWithOffsetX:(CGFloat)targetX{
    //计算当前mainV的frame.
    targetX -= self.mainV.frame.origin.x;
    [UIView animateWithDuration:0.5 animations:^{
        self.mainV.frame = [self frameWithOffsetX:targetX];
    }];
}
#define maxY 100
//根据偏移量计算MainV的frame
- (CGRect)frameWithOffsetX:(CGFloat)offsetX {
    
    NSLog(@"offsetX===%f",offsetX);
    
    CGRect frame = self.mainV.frame;
    NSLog(@"x====%f",frame.origin.x);
    frame.origin.x += offsetX;

    //当拖动的View的x值等于屏幕宽度时,maxY为最大,最大为100
    // 375 * 100 / 375 = 100
    
    //对计算的结果取绝对值
    CGFloat y =  fabs( frame.origin.x *  maxY / screenW);
    frame.origin.y = y;
    
    
    //屏幕的高度减去两倍的Y值
    frame.size.height = [UIScreen mainScreen].bounds.size.height - (2 * frame.origin.y);
    
    return frame;
}




- (void)setUp{
    //leftV
    UIView *leftV = [[UIView alloc] initWithFrame:self.view.bounds];
    leftV.backgroundColor = [UIColor blueColor];
    //self.leftV = leftV;
    _leftV = leftV;
    [self.view addSubview:leftV];
    //rightV
    UIView *rightV = [[UIView alloc] initWithFrame:self.view.bounds];
    rightV.backgroundColor = [UIColor greenColor];
    //self.rightV = rightV;
    _rightV = rightV;
    [self.view addSubview:rightV];
    //mianV
    UIView *mainV = [[UIView alloc] initWithFrame:self.view.bounds];
    mainV.backgroundColor = [UIColor redColor];
    //self.mainV = mainV;
    _mainV = mainV;
    [self.view addSubview:mainV];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end