iOS开发实用技巧—项目新特性页面的处理

说明：本文主要说明在项目开发中会涉及到的最最简单的新特性界面（实用UIScrollView展示多张图片的轮播）的处理。

代码示例：

新建一个专门的处理新特性界面的控制器，可以实用代码也可以用xib，在这里实用纯代码方式，创建一个控制器NewfeatureViewController。

头文件代码：

//
//  JMNewfeatureViewController.h
//

#import <UIKit/UIKit.h>

typedef enum:NSInteger
{
    NewfeatureTypeFromeSetting,     //从设置界面进入该页
    NewfeatureTypeFromeWelcom,      //第一次安装的时候进入
} NewfeatureType;

@interface JMNewfeatureViewController : UIViewController

@property(nonatomic,assign)NewfeatureType newfeatureType;

@end

.m文件代码：

//
//  JMNewfeatureViewController.m
//

#import "JMNewfeatureViewController.h"
#import "JMTabBarViewController.h"
#import "JMAboutTableViewController.h"

#define JMNewfeatureImageCount 4

@interface JMNewfeatureViewController () <UIScrollViewDelegate>

@property (nonatomic, weak) UIPageControl *pageControl;


- (void)setupScrollView;
- (void)setupPageControl;
- (void)setupLastImageView:(UIImageView *)imageView;
- (void)setupStartButton:(UIImageView *)imageView;

@end

@implementation JMNewfeatureViewController

#pragma mark ---------------------
#pragma mark - CycLife

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    [UIApplication sharedApplication].statusBarHidden = YES;
    
    [self setupScrollView]; // 添加UISrollView
    [self setupPageControl];    // 添加pageControl
}

#pragma mark ---------------------
#pragma mark - Methods

//添加UISrollView
- (void)setupScrollView
{
    // 添加UISrollView
    UIScrollView *scrollView = [[UIScrollView alloc] init];
    scrollView.frame = self.view.bounds;
    scrollView.bounces = NO;
    scrollView.delegate = self;
    [self.view addSubview:scrollView];
    
    // 添加图片
    CGFloat imageW = scrollView.width;
    CGFloat imageH = scrollView.height;
    for (int i = 0; i<JMNewfeatureImageCount; i++) {
        // 创建UIImageView
        UIImageView *imageView = [[UIImageView alloc] init];
        NSString *name = [NSString stringWithFormat:@"banner%d.jpg", i + 1];
        imageView.image = [UIImage imageNamed:name];
        [scrollView addSubview:imageView];
        
        // 设置frame
        imageView.y = 0;
        imageView.width = imageW;
        imageView.height = imageH;
        imageView.x = i * imageW;
        
        // 给最后一个imageView添加按钮
        if (i == JMNewfeatureImageCount - 1) {
            [self setupLastImageView:imageView];
        }
    }
    
    // 3.设置其他属性
    scrollView.contentSize = CGSizeMake(JMNewfeatureImageCount * imageW, 0);
    scrollView.pagingEnabled = YES;
    scrollView.showsHorizontalScrollIndicator = NO;
    scrollView.backgroundColor = YYColor(246, 246, 246);
}

//添加pageControl
- (void)setupPageControl
{
    // 添加PageControl
    UIPageControl *pageControl = [[UIPageControl alloc] init];
    pageControl.numberOfPages = JMNewfeatureImageCount;
    pageControl.centerX = self.view.width * 0.5;
    pageControl.centerY = self.view.height - 20;
    [self.view addSubview:pageControl];

    // 设置圆点的颜色
    self.pageControl = pageControl;
    [self changePageControlImage:self.pageControl];
}


//设置最后一个UIImageView中的内容
- (void)setupLastImageView:(UIImageView *)imageView
{
    imageView.userInteractionEnabled = YES;
    
    // 添加开始按钮
    [self setupStartButton:imageView];
}

//添加开始按钮
- (void)setupStartButton:(UIImageView *)imageView
{
    // 1.添加开始按钮
    UIButton *startButton = [[UIButton alloc] init];
    imageView.userInteractionEnabled = YES;
    [imageView addSubview:startButton];
    
    // 2.设置背景图片
    [startButton setBackgroundImage:[UIImage imageNamed:@"banner_button_moren.jpg"] forState:UIControlStateNormal];
    [startButton setBackgroundImage:[UIImage imageNamed:@"banner_button_dianji.jpg"] forState:UIControlStateHighlighted];
    
    // 3.设置frame
    startButton.size = startButton.currentBackgroundImage.size;
    startButton.centerX = self.view.width * 0.5;
    startButton.centerY = self.view.height * 0.8;
    
    // 4.设置文字
    [startButton setTitle:@"立即体验" forState:UIControlStateNormal];
     [startButton setTitle:@"" forState:UIControlStateHighlighted];
    [startButton addTarget:self action:@selector(start) forControlEvents:UIControlEventTouchUpInside];
}


//改变pagecontrol中圆点样式
- (void)changePageControlImage:(UIPageControl *)pageControl
{
    static UIImage *imgCurrent = nil;
    static UIImage *imgOther = nil;
    static dispatch_once_t onceToken;
    
    dispatch_once(&onceToken, ^{
        imgCurrent = [UIImage imageNamed:@"yuan_01"];
        imgOther = [UIImage imageNamed:@"yuan1"];
    });
    
    
    if (kSystemVersionMoreThan7) {
        [pageControl setValue:imgCurrent forKey:@"_currentPageImage"];
        [pageControl setValue:imgOther forKey:@"_pageImage"];
    } else {
        for (int i = 0;i < pageControl.numberOfPages; i++) {
            UIImageView *imgv = [pageControl.subviews objectAtIndex:i];
            imgv.frame = CGRectMake(imgv.frame.origin.x, imgv.frame.origin.y, 20, 20);
            imgv.image = pageControl.currentPage == i ? imgCurrent : imgOther;
        }
    }
}

#pragma mark ---------------------
#pragma mark - Events

//立即体验
- (void)start
{
    [UIApplication sharedApplication].statusBarHidden = NO;
    
    //判断类型
    if (self.newfeatureType == NewfeatureTypeFromeWelcom) {
        JMTabBarViewController *tabVC = [[JMTabBarViewController alloc]init];
        // 切换控制器
        UIWindow *window = [UIApplication sharedApplication].keyWindow;
        window.rootViewController = tabVC;
    }else 
    {
        
        [self.navigationController popViewControllerAnimated:YES];
        [self.navigationController setNavigationBarHidden:NO animated:NO];
    }
  
}

#pragma mark - UIScrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // 获得页码
    CGFloat doublePage = scrollView.contentOffset.x / scrollView.width;
    int intPage = (int)(doublePage + 0.5);
    
    // 设置页码
    self.pageControl.currentPage = intPage;
    [self changePageControlImage:self.pageControl];
}

@end

注意点：

　　下面的方法可以为pageControl提供当前状态和默认状态下的图片设置。

//改变pagecontrol中圆点样式
- (void)changePageControlImage:(UIPageControl *)pageControl
{
    static UIImage *imgCurrent = nil;
    static UIImage *imgOther = nil;
    static dispatch_once_t onceToken;
    
    dispatch_once(&onceToken, ^{
        imgCurrent = [UIImage imageNamed:@"yuan_01"];
        imgOther = [UIImage imageNamed:@"yuan1"];
    });
    
    
    if (kSystemVersionMoreThan7) {
        [pageControl setValue:imgCurrent forKey:@"_currentPageImage"];
        [pageControl setValue:imgOther forKey:@"_pageImage"];
    } else {
        for (int i = 0;i < pageControl.numberOfPages; i++) {
            UIImageView *imgv = [pageControl.subviews objectAtIndex:i];
            imgv.frame = CGRectMake(imgv.frame.origin.x, imgv.frame.origin.y, 20, 20);
            imgv.image = pageControl.currentPage == i ? imgCurrent : imgOther;
        }
    }
}

本例中，新特性部分的业务逻辑非常简单，可以直接套用。

实用图片替换pageControl的效果如下：