实现简易抽屉效果和双边抽屉的效果

@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) {    }];}

#import "PathView.h"#import "UIView+Additions.h" @implementation PathView - (instancetype)init { self = [super init]; if (self) {  [self setupGestureRecognizer]; } return self;} - (void)setupGestureRecognizer { UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; [self addGestureRecognizer:pan];} - (void)handlePan:(UIPanGestureRecognizer*)recognizer { CGPoint translation = [recognizer translationInView:self];   CGFloat Xresult = translation.x + self.left;   if (translation.x >= 0) {//向右  if (self.left >= _leftWidth || Xresult >= _leftWidth) {   self.frame = CGRectMake(_leftWidth, 0, self.width, self.height);   return;  } } else if (translation.x < 0) {//向左  if (self.left <= -_rightWidth || Xresult <= -_rightWidth) {   self.frame = CGRectMake(-_rightWidth, 0, self.width, self.height);   return;  } }   self.left += translation.x;   if (recognizer.state == UIGestureRecognizerStateEnded) {  if (self.left > _leftWidth / 2) {   [self openLeft:YES openRight:NO];  }     else if (self.left < -(_rightWidth / 2)) {   [self openLeft:NO openRight:YES];  }     else {   [self openLeft:NO openRight:NO];  } }   //清空移动的距离 [recognizer setTranslation:CGPointZero inView:recognizer.view];} - (void)openLeft:(BOOL)left openRight:(BOOL)right { if (!left && !right) {  [self moveView:CGRectMake(0, 0, self.width, self.height)];    } else if (!left && right) {  [self moveView:CGRectMake(-_rightWidth, 0, self.width, self.height)];    } else if (left && !right) {  [self moveView:CGRectMake(_leftWidth, 0, self.width, self.height)];    }} - (void)moveView:(CGRect)frame { [UIView animateWithDuration:0.3 animations:^{  self.frame = frame; } completion:^(BOOL finished) {    }];}