iOS 仿百度外卖-首页重力感应的实例

今天带来的是仿百度外卖首页的重力感应..(由于只能真机测试,手里测试机只有5s,所以有些地方并没有适配其他机型,需要的还需要根据真机自行适配)

来简单说下实现吧,之前重力感应都是用UIAccelerometer实现的,但是,好像是从iOS 4 以后,这个方法就废弃了,它被直接封装到了CoreMotion框架中,所以现在有关重力感应,加速计什么的都需要通过CoreMotion框架实现,这也算是苹果对于重力感应的整合吧.本文对CoreMotion框架只是进行了简单的使用,想要更深的使用,还是请自行 google(百度上的文档非常少).

好了.下面就是实现代码

(注意这里需要导入系统框架CoreMotion.framework)

//
// 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 <CoreMotion/CoreMotion.h> 

@interface ViewController ()<UIScrollViewDelegate>{ 

  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",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 

到这里,就可以进行真机测试了..

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。