思路来自 http://www.jianshu.com/p/e52806516139 和 http://www.jianshu.com/p/ffa65292abf2, 在此感谢
广告图片肯定是通过一个接口从网络异步请求, 如果让我们的app安装之后就显示, 这样的话肯定会出现一开始打开app一片空白的情况, 所以在第一次安装时, 先不显示广告, 只显示引导页, 在后台请求广告图并缓存, 等第二次启动及以后再显示
我们需要配合NSUserDefault存储图片名字, 便于下次取出之后拼接沙河路径取出使用
首先声明一个全局静态变量
static NSString *const NAImageName = @"NAImageName";
在
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{}中
先利用NSUserDefault保存的图片名, 取出并拼接成沙盒路径去查找是否存有广告图, 有则进行显示, 没有直接进入app首页
//1.判断沙盒中是否存在广告图片, 如果存在, 直接显示, 不存在就先进入app首页
NSString *filePath = [self getFilePathWithImageName:[[NSUserDefaults standardUserDefaults] valueForKey:NAImageName]];
BOOL isExist = [[NSFileManager defaultManager] fileExistsAtPath:filePath];
//如果图片存在
if (isExist) {
//展示
NAAdView *adView = [[NAAdView alloc] initWithFrame:self.window.bounds];
adView.filePath = filePath;
[adView show];
}
else{
NSLog(@"图片不存在");
}
当然, 无论是否存在, 每次启动都要请求接口确保本地存的广告图是最新的
//2.无论存不存在, 都进行网络请求获取最新的网络图片, 然后存入沙盒
[self requestAdImage];
从
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{}
出来之后, 以下是拼接沙河路径的方法
- (NSString *)getFilePathWithImageName:(NSString *)imageName{
if (imageName) {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *filePath = [paths.firstObject stringByAppendingPathComponent:imageName];
// NSLog(@"%@", filePath);
return filePath;
}
return nil;
}
网络获取图片这一块, 因为暂时没有接口, 就用一个数组存了若干图片url, 每次随机取出一个, 取url最后一段作为图片名
#pragma mark - 网络获取图片
- (void)requestAdImage{
NSArray *imageArray = @[@"http://imgsrc.baidu.com/forum/pic/item/9213b07eca80653846dc8fab97dda144ad348257.jpg", @"http://pic.paopaoche.net/up/2012-2/20122220201612322865.png", @"http://img5.pcpop.com/ArticleImages/picshow/0x0/20110801/2011080114495843125.jpg", @"http://www.mangowed.com/uploads/allimg/130410/1-130410215449417.jpg"];
NSString *imageUrl = imageArray[arc4random() % imageArray.count];
//把获取的网址字符串按"/"分割成几部分组成数组
NSArray *stringArr = [imageUrl componentsSeparatedByString:@"/"];
NSString *imageName = stringArr.lastObject;
//拼接沙盒路径
NSString *filePath = [self getFilePathWithImageName:imageName];
BOOL isExist = [self isFileExistWithFilePath:filePath];
//如果图片不存在, 删除老图片, 网络获取并存入沙盒
if (!isExist) {
[self downloadAdImageWithUrl:imageUrl imageName:imageName];
}
}
检查这条文件路径是否存在
#pragma mark - 检查文件路径是否存在
- (BOOL)isFileExistWithFilePath:(NSString *)filePath{
BOOL isDirectory = NO;
return [[NSFileManager defaultManager] fileExistsAtPath:filePath isDirectory:&isDirectory];
}
如果不存在, 开始异步下载
#pragma mark - 异步下载图片
- (void)downloadAdImageWithUrl:(NSString *)imageUrl imageName:(NSString *)imageName{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//网络获取
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageUrl]];
UIImage *image = [UIImage imageWithData:data];
NSString *filePath = [self getFilePathWithImageName:imageName];
if ([UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES]) {
[self deleteOldImage];
[[NSUserDefaults standardUserDefaults] setValue:imageName forKey:NAImageName];
[[NSUserDefaults standardUserDefaults] synchronize];
}
else{
NSLog(@"保存失败");
}
});
}
如果存储了新图片, 那就把旧图片删除
#pragma mark - 删除旧图片
- (void)deleteOldImage{
NSString *imageName = [[NSUserDefaults standardUserDefaults] valueForKey:NAImageName];
if (imageName) {
NSString *filePath = [self getFilePathWithImageName:imageName];
NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager removeItemAtPath:filePath error:nil];
}
}
==============我是分割线=========================
以上是appDelegate我们需要做的
接下来是广告图的页面
创建一个NAAdView继承于UIView
在.h中把图片存储路径属性和开始展示的方法声明出去
来到.m
声明了以下这几个属性
@property (nonatomic, strong) UIImageView *imageViewOfAd;//广告图
@property (nonatomic, strong) UIButton *buttonOfCount;//退出按钮
@property (nonatomic, strong) NSTimer *timer;//计时器
@property (nonatomic, assign) NSInteger count;//监听当前倒数的数字
先声明一个静态常量用于规定倒计时的数字, 方便以后进行更改
static NSInteger const showTime = 3;
接下来就是重写初始化方法, 配置子视图和计时器, 并添加轻拍手势, 用于发送通知让首页push到广告页
- (instancetype)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
[self configSubviews];
}
return self;
}
#pragma mark - 配置子视图
- (void)configSubviews{
//1.广告图
_imageViewOfAd = [[UIImageView alloc] initWithFrame:self.frame];
_imageViewOfAd.userInteractionEnabled = YES;
_imageViewOfAd.contentMode = UIViewContentModeScaleAspectFill;
_imageViewOfAd.clipsToBounds = YES;
[self addSubview:_imageViewOfAd];
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(pushToAdPage:)];
[_imageViewOfAd addGestureRecognizer:tap];
//2.跳过按钮
CGFloat btnW = 60;
CGFloat btnH = 30;
_buttonOfCount = [UIButton buttonWithType:UIButtonTypeCustom];
_buttonOfCount.frame = CGRectMake(SCREEN_WIDTH - btnW - 24, btnH, btnW, btnH);
[_buttonOfCount addTarget:self action:@selector(dismiss:) forControlEvents:UIControlEventTouchUpInside];
[_buttonOfCount setTitle:[NSString stringWithFormat:@"跳过%ld", showTime] forState:UIControlStateNormal];
_buttonOfCount.titleLabel.font = [UIFont systemFontOfSize:15];
[_buttonOfCount setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
_buttonOfCount.backgroundColor = [UIColor colorWithRed:38 /255.0 green:38 /255.0 blue:38 /255.0 alpha:0.6];
[self addSubview:_buttonOfCount];
//3.定时器
_timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerAction:) userInfo:nil repeats:YES];
}
#pragma mark - 计时器事件
- (void)timerAction:(NSTimer *)timer{
_count--;
[_buttonOfCount setTitle:[NSString stringWithFormat:@"跳过%ld", _count] forState:UIControlStateNormal];
if(_count == 0){
//计时器失效, 页面退下
[self dismiss:nil];
}
}
#pragma mark - 轻拍手势响应事件, 跳转到广告页
- (void)pushToAdPage:(UITapGestureRecognizer *)tap{
[self dismiss:nil];
//发送通知让界面跳转
[[NSNotificationCenter defaultCenter] postNotificationName:@"goToAdPage" object:nil];
}
#pragma mark - 页面消失
- (void)dismiss:(UIButton *)button{
[_timer invalidate];
_timer = nil;
[UIView animateWithDuration:.5f animations:^{
self.alpha = 0.f;
} completion:^(BOOL finished) {
[self removeFromSuperview];
}];
}
只有当这个show方法在appDelegate被调用, 视图才会被添加到UIWindow上, 计时器才会加入到runLoop开始执行, 外部也会赋值一个沙盒路径进来, 让NAAdView的imageView取出图片来使用
#pragma mark - 开始展示
- (void)show{
[self startTimer];
UIWindow *window = [UIApplication sharedApplication].keyWindow;
// window.hidden = NO;
[window addSubview:self];
}
#pragma mark - 开始计时
- (void)startTimer{
_count = showTime;
[[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];
}
#pragma mark - 重写图片路径setter
- (void)setFilePath:(NSString *)filePath{
_filePath = filePath;
_imageViewOfAd.image = [UIImage imageWithContentsOfFile:filePath];
NSLog(@"^^^^^%@", filePath);
}
