直接在controller里面加代码实现的抽屉效果

@interface ViewController () {
    UIView* _leftView;
}
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
     
    _leftView = [[UIView alloc] init];
    //把左侧边的view先隐藏
    _leftView.frame = CGRectMake(-200, 0, 200, self.view.frame.size.height);
    _leftView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:_leftView];
     
    UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
    [self.view addGestureRecognizer:pan];
}
 
- (void)handlePan:(UIPanGestureRecognizer*) recognizer {
    CGPoint translation = [recognizer translationInView:self.view];
    //增量后的x坐标位置
    CGFloat Xresult = translation.x + _leftView.frame.origin.x;
     
    //向右
    if (translation.x >= 0) {
        //leftView已全部拉出，则无法再向右
        if (_leftView.frame.origin.x >= 0 || Xresult >= 0) {
            _leftView.frame = CGRectMake(0, 0, 200, self.view.frame.size.height);
             
            return;
        }
    } else if (translation.x < 0) {//向左
        //leftView已全部收回，则无法再向左
        if (_leftView.frame.origin.x <= -200 || Xresult <= -200) {
            _leftView.frame = CGRectMake(-200, 0, 200, self.view.frame.size.height);
            return;
        }
    }
     
    CGRect frame = _leftView.frame;
    frame.origin.x += translation.x;
    _leftView.frame = frame;
     
    //清空移动的距离，这是关键
    [recognizer setTranslation:CGPointZero inView:recognizer.view];
     
    //做弹回效果，以中轴为界限
    if (recognizer.state == UIGestureRecognizerStateEnded) {
        if (_leftView.frame.origin.x > -100) {
            [self closeView:NO];
        } else {
            [self closeView:YES];
        }
    }
}
 
- (void)closeView:(BOOL)close {
    if (close) {
        [self moveView:CGRectMake(-200, 0, 200, self.view.frame.size.height)];
    } else {
        [self moveView:CGRectMake(0, 0, 200, self.view.frame.size.height)];
    }
}
 
- (void)moveView:(CGRect)frame {
    [UIView animateWithDuration:0.3 animations:^{
        _leftView.frame = frame;
    } completion:^(BOOL finished) {
         
    }];
}