一个简单的抽屉效果,简单实用!
整体思路:
主要是在控制器的View上添加了两个View,一个左侧leftView和一个mainView,给mainView添加手势,动画效果,根据计算判断偏移量的X值是否大于leftView的宽度的一半;

iOS中抽屉效果的封装

#import "XBViewController.h"
#define SWIDTH [UIScreen mainScreen].bounds.size.width
@interface XBViewController ()
/**自定义View */
@property (strong, nonatomic) UIView *mainV;
@property (nonatomic ,weak) UIView *leftV;

@end

@implementation XBViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // 添加界面
    [self setView];
    //创建手势
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];
     // 添加手势
    [self.mainV addGestureRecognizer:pan];
    //添加点按手势,点击时关闭
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(close)];
    [self.leftV addGestureRecognizer:tap];
}

- (void)close
{
    [UIView animateWithDuration:1.5 animations:^{
        self.mainV.transform = CGAffineTransformIdentity;
        self.mainV.frame = self.view.bounds;
    }];
}
#define tartgetR SWIDTH * 0.8
// 实现手势方法
- (void)pan:(UIPanGestureRecognizer *)pan
{
     //获取偏移量(是相对于最原始的点,起点的偏移量)
    CGPoint tranP = [pan translationInView:_mainV];
    //计算当前MainV的位置,大小
    [self positionWithOffset:tranP.x];
     //判断手势的状态
    if (pan.state == UIGestureRecognizerStateEnded) {
        if (self.mainV.frame.origin.x > SWIDTH * 0.5) {
            [UIView animateWithDuration:1.5 delay:0 options:UIViewAnimationOptionCurveEaseIn animations:^{
                // 自动定位到右侧
                CGFloat offset = tartgetR - self.mainV.frame.origin.x;
                [self positionWithOffset:offset];
            } completion:nil];
        }else{
            [self close];
        }

    }
    // 把偏移量做一次复位,清0(不让偏移量进行累加)
    [pan setTranslation:CGPointZero inView:self.mainV];
}
// 计算偏移量
#define maxScale 0.3
- (void)positionWithOffset:(CGFloat)offset {

    //获取Frame
    CGRect frame = self.mainV.frame;
    frame.origin.x += offset;
    self.mainV.frame = frame;
    //只能往右边拖动
    if (frame.origin.x<=0) {
        self.mainV.frame = [UIScreen mainScreen].bounds;
    }
    //最大值是多少
    // 什么时候为最大
    CGFloat scale = frame.origin.x * maxScale / SWIDTH;
    // 计算缩放比例
    scale = 1 - scale;
    if (scale >= 1) {
        scale = 1;
    }
    // 缩放
    self.mainV.transform = CGAffineTransformMakeScale(scale, scale);
}

#pragma mark - 添加View

- (void)setView
{
    // 添加左边的View
    UIView *leftV = [[UIView alloc]initWithFrame:self.view.bounds];
    leftV.backgroundColor = [UIColor blueColor];
    [self.view addSubview:leftV];

    //mainV
    UIView *mainV = [[UIView alloc]initWithFrame:self.view.bounds];
    mainV.backgroundColor = [UIColor redColor];
    [self.view addSubview:mainV];
    self.mainV = mainV;
}

@end

效果图:

图片弹出缩放.gif