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..
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