简单的iOS抽屉效果

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

#import "ViewController.h"

@interface ViewController ()

@property (nonatomic,strong)UIView * redView;

@property (nonatomic,strong)UIView *yellowView;

@property (nonatomic,strong)UIView *greenView;

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

[self setUpView];

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];

[self.view addGestureRecognizer:pan];

}

//根据当前最前面视图的frame确定是否隐藏第二个View

- (void)Hidden{

if (self.greenView.frame.origin.x>0) {//往右移动,显示黄色的View

self.yellowView.hidden = NO;

}else if (self.greenView.frame.origin.x<0){//往左移动,隐藏黄色的View

self.yellowView.hidden = YES;

}

}

#define rightLocation 275

#define leftLocation -250

#pragma mark pan的方法

- (void)pan:(UIPanGestureRecognizer *)pan{

//获取手势移动的位置

CGPoint point = [pan translationInView:self.view];

//获取X轴的偏移量

CGFloat offSetX = point.x;

//修改greenView的frame

self.greenView.frame =  [self changeFrameWith:offSetX];

//判断greenViewdex是否大于0

[self Hidden];

//复位

[pan setTranslation:CGPointZero inView:self.view];

//判断下当手势结束的时候,定位

if (pan.state == UIGestureRecognizerStateEnded) {

CGFloat target = 0;

if (self.greenView.frame.origin.x > screenW * 0.5) {

target = rightLocation;

}else if (CGRectGetMaxX(self.greenView.frame)<screenW * 0.5){

target = leftLocation;

}

//获取偏移量

CGFloat offSetX = target-self.greenView.frame.origin.x;

[UIView animateWithDuration:0.25 animations:^{

self.greenView.frame = target == 0?self.view.bounds:[self changeFrameWith:offSetX];

}];

}

}

#define MaxY  100

//根据偏移量获取一个新的frame

#pragma mark - 根据offSetX计算greenView的frame

- (CGRect)changeFrameWith:(CGFloat)offSetX{

//获取上一次的frame

CGRect frame = self.greenView.frame;

//获取上一次的高和宽

CGFloat oldW = frame.size.width;

CGFloat oldH = frame.size.height;

//移动后的x

CGFloat curX =frame.origin.x + offSetX;

//y轴方向偏移量

CGFloat offsetY = offSetX*MaxY/screenW;

//当前的frame高度

CGFloat curH = frame.size.height - 2*offsetY;

if (frame.origin.x<0) {//往左移动

curH = oldH+2*offsetY;

}

//获取尺寸的缩放比例

CGFloat scale = curH/oldH;

CGFloat curW = oldW * scale;

CGFloat curY = (self.view.frame.size.height - curH)*0.5;

//更改frame

frame.origin.x = curX;

frame.origin.y = curY;

frame.size.width = curW;

frame.size.height = curH;

return frame;

}

#pragma mark 添加View

- (void)setUpView{

self.redView = [[UIView alloc]initWithFrame:self.view.frame];

self.redView.backgroundColor = [UIColor redColor];

[self.view addSubview:self.redView];

self.yellowView = [[UIView alloc]initWithFrame:self.view.frame];

self.yellowView.backgroundColor = [UIColor yellowColor];

[self.view addSubview:self.yellowView];

self.greenView = [[UIView alloc]initWithFrame:self.view.frame];

self.greenView.backgroundColor = [UIColor greenColor];

[self.view addSubview:self.greenView];

}

@end