iOS 仿百度外卖-首页重力感应的实例

 // // ViewController.m // 仿百度外卖首页-重力感应 // // Created by Amydom on 16/12/5. // Copyright © 2016年 Amydom. All rights reserved. // #import "ViewController.h" #import  @interface ViewController (){ NSTimeInterval updateInterval; CGFloat setx;//scroll的动态偏移量 } @property (nonatomic,strong) CMMotionManager *mManager; @property (nonatomic , strong)UIScrollView *myScrollView; @property (nonatomic , assign)CGFloat offsetX;//初始偏移量 @property (nonatomic , assign)NSInteger offset; @end @implementation ViewController - (void)viewDidAppear:(BOOL)animated_{ [super viewDidAppear:animated_]; //在界面已经显示后在调用方法(优化) [self startUpdateAccelerometerResult:0]; } - (void)viewDidLoad { [super viewDidLoad]; self.view.backgroundColor = [UIColor whiteColor]; [self createView]; } - (void)createView{ //collectionView UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc]init]; UICollectionView *myCollection = [[UICollectionView alloc]initWithFrame:[UIScreen mainScreen].bounds collectionViewLayout:flowLayout]; myCollection.backgroundColor = [UIColor whiteColor]; [self.view addSubview:myCollection]; _myScrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 22, self.view.frame.size.width, 100)]; _myScrollView.backgroundColor = [UIColor lightGrayColor]; _myScrollView.delegate = self; [self.view addSubview:_myScrollView]; for (int i = 0; i <8; i ++) { NSString *name = [NSString stringWithFormat:@"%d.jpg-600",i + 1]; UIImageView *image = [[UIImageView alloc]initWithFrame:CGRectMake(5 + 885 * i, 10, 80, 80)]; image.image = [UIImage imageNamed:name]; image.backgroundColor = [UIColor orangeColor]; image.layer.masksToBounds = YES; image.layer.cornerRadius = 40; [_myScrollView addSubview:image]; //偏移量为最后 image 的 frame + origin _myScrollView.contentSize = CGSizeMake (image.frame.size.width + image.frame.origin.x, 10); } } //手指触碰时 - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{ _offsetX = scrollView.contentOffset.x; [self stopUpdate]; } - (void)scrollViewDidScroll:(UIScrollView *)scrollView{ //优化处理 setx = scrollView.contentOffset.x; _offset = scrollView.contentOffset.x - _offsetX; if (_offset > 0) { //left }else{ //right } } //手指离开时 - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ [self startUpdateAccelerometerResult:0]; } #pragma mark - 重力感应 - (CMMotionManager *)mManager { if (!_mManager) { updateInterval = 1.0/15.0; _mManager = [[CMMotionManager alloc] init]; } return _mManager; } //开始 - (void)startUpdateAccelerometerResult:(void (^)(NSInteger))result { if ([self.mManager isAccelerometerAvailable] == YES) { //回调会一直调用,建议获取到就调用下面的停止方法，需要再重新开始，当然如果需求是实时不间断的话可以等离开页面之后再stop [self.mManager setAccelerometerUpdateInterval:updateInterval]; [self.mManager startAccelerometerUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMAccelerometerData *accelerometerData, NSError *error) { double x = accelerometerData.acceleration.x; double y = accelerometerData.acceleration.y; if (fabs(y) >= fabs(x)) {//前后 if (y >= 0){ //Down } else{ //Portrait } } else { //左右 if (x >= 0){ setx += 10; if (setx <= 360) { //由于以10为单位改变 contentOffset, 会出现顿的现象,加上动画就可解决这个问题 [UIView animateWithDuration:0.1 animations:^{ _myScrollView.contentOffset = CGPointMake(setx, 0); }]; //模仿 scroll 的回弹效果 if (setx == 360) { [UIView animateWithDuration:0.5 animations:^{ _myScrollView.contentOffset = CGPointMake(setx + 50, 0); } completion:^(BOOL finished) { [UIView animateWithDuration:0.5 animations:^{ _myScrollView.contentOffset = CGPointMake(setx , 0); }]; }]; } }else{ setx = 360; } }else{ setx -= 10; if (setx >= 0) { [UIView animateWithDuration:0.1 animations:^{ _myScrollView.contentOffset = CGPointMake(setx, 0); }]; //模仿 scroll 的回弹效果 if (setx == 0) { [UIView animateWithDuration:0.5 animations:^{ _myScrollView.contentOffset = CGPointMake(setx - 50, 0); } completion:^(BOOL finished) { [UIView animateWithDuration:0.5 animations:^{ _myScrollView.contentOffset = CGPointMake(setx, 0); }]; }]; } }else{ setx = 0; } } } }]; } } //停止感应方法 - (void)stopUpdate { if ([self.mManager isAccelerometerActive] == YES) { [self.mManager stopAccelerometerUpdates]; } } //离开页面后停止(移除 mManager) - (void)dealloc { //制空,防止野指针 _mManager = nil; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end