项目一（电影APP）——iOS学习连载26

1.删除系统的tabbarItem

NSArray *array =self.tabBar.subviews;

//注意：UITabBarButton是一个私有的API，没有公开出来

//遍历tabbar中所有的子视图，并且移除tabbarItem

for(UIView*view in array) {

    Class cls =NSClassFromString(@"UITabBarButton");

   if ([view isKindOfClass: cls]) {

    //移除tabbar上的按钮

     [viewremoveFromSuperview];

     }

2.动画修改选择视图的坐标

  [UIViewanimateWithDuration:0.3

                    animations:^{

                  _selectedImgView.center = item.center;

                     }];

3.第一次添加到控制器视图上的子视图如果是ScrollView的对象（包含ScrollView子类的对象）,则视图的内容偏移量会根据是否有导航栏和标签栏进行扩充

4.配置翻转动画(此方法与下面方法比较需要去求得翻转图片的下标)

        [UIViewtransitionWithView:imgView

                         duration:0.5

                          options:UIViewAnimationOptionTransitionFlipFromLeft
                        animations:^{
                            [self.viewexchangeSubviewAtIndex:index1withSubviewAtIndex:index2];
                        }

                       completion:nil];

5.翻转forView的两个子视图（forView：需要被翻转视图的父视图；flag：是否从左往右翻转）

//翻转视图

[selfflipView:self.viewleft:btn1.hidden];

- (void)flipView:(UIView*)forView left:(BOOL)flag
{
    UIViewAnimationOptions flip;
    if(flag)

    {

      flip =UIViewAnimationOptionTransitionFlipFromLeft;

    }
    else

    {

     flip =UIViewAnimationOptionTransitionFlipFromRight;

    }
   
    //翻转
    [UIViewtransitionWithView:forViewduration:0.5options:flipanimations:^{
       
    } completion:nil];

}

6.在iOS5.0之前解析json数据 ——> 使用第三方json解析工具: jsonKit/TouchJson/SBJson

 iOS5.0之后 ——> 使用NSJSONSerialization解析

7.//找到json数据路径

NSString *filePath = [[NSBundlemainBundle] pathForResource:us_box ofType:@"json"];

//从文件路径中获取数据

NSData *data = [NSDatadataWithContentsOfFile:filePath];

//解析json----》转换成NSDictionary或者是NSArray

NSError*error = nil;

NSDictionary *jsonDic = [NSJSONSerializationJSONObjectWithData:data options:NSJSONReadingMutableContainerserror:&error];

8.//拿到图片地址

NSString *urlStr = [self.movie.imagesobjectForKey:@"medium"];

//构建URL方法一

NSURL*imgurl = [NSURLURLWithString:urlStr];

[_imgViewsd_setImageWithURL:imgurl];

//构建URL方法二

NSURL*imgurl = [NSURLURLWithString:urlStr];

NSData*data = [NSDatadataWithContentsOfURL:imgurl];

self.imageView.image = [UIImage imageWithData:data];

9.当视图修改了transform后，坐标会变，需要重新恢复坐标

    CGPointMake(0, 0)与CGPointZero等效

10.只要改变数据源，就要刷新tableView

11.隐藏状态栏

- (BOOL)prefersStatusBarHidden
{
    return self.navigationController.navigationBarHidden;
}

- (UIStatusBarAnimation)preferredStatusBarUpdateAnimation
{
    return UIStatusBarAnimationFade;

}

12.view =  layer +事件接收

13.设置边框宽度

  userImage.layer.borderWidth= 1;

 //设置边框颜色

 userImage.layer.borderColor = [UIColorwhiteColor].CGColor;

14.把头像设置为圆形， 设置圆角半径

    userImage.layer.cornerRadius = 27;//（27为正方形图片边长的一半）

   userImage.layer.masksToBounds =YES; //剪切多余部分

15.把图片的宽从0、高从10像素开始画，直到填充整个imgview，可以避免图片拉伸

   UIImage*img = [ImgView.imagestretchableImageWithLeftCapWidth:0topCapHeight:10];

   ImgView.image = img;

 16./****判断是否是第一次启动，用于设置第一次启动的启动页面****/

   //获取沙盒目录
    NSString *filePath = [NSHomeDirectory()stringByAppendingPathComponent:@"Documents/wx47.plist"];
    //区分第一次启动还是以后启动的
    NSDictionary *dic = [NSDictionarydictionaryWithContentsOfFile:filePath];
    if (dic == nil) {
        //第一次运行
        [self_initFirstOpenView];
        dic = @{@"first":@"YES"};
        //把一个字典写入到文件
        [dic writeToFile:filePathatomically:YES];

    }

17.清除缓存

- (void)_countCacheSize

{
    //获取应用程序的沙盒路径
    NSString *homePath =NSHomeDirectory();
//    NSLog(@"homePath is %@", homePath);
   
    //拼接出缓存路径
    NSString *imgPath = [homePathstringByAppendingPathComponent:@"Library/Caches/default/com.hackemist.SDWebImageCache.default"];
   
    //文件管理助手（管家）---->单利对象
    NSFileManager *fileManager = [NSFileManagerdefaultManager];
   
    //取得一个文件夹下所有的文件路径
    NSError *error = nil;

   NSArray *subPath = [fileManager subpathsOfDirectoryAtPath:imgPath error:&error];

   
    long long sum = 0;
   
    for (NSString*filePath in subPath) {
        //取得一个文件的路径
        NSString *path = [imgPathstringByAppendingPathComponent:filePath];
       
        //拿到文件的属性
        NSDictionary *attributes = [fileManagerattributesOfItemAtPath:patherror:&error];
       
        //取出文件的大小
        NSNumber *filesize = attributes[NSFileSize];
       
        sum += [filesize longLongValue];
       

    }

   
    cacheSize = sum / (1000.0* 1000);
    NSLog(@"cacheSize is %.2f",cacheSize);
   

}

- (void)tableView:(UITableView*)tableView willDisplayCell:(UITableViewCell*)cell forRowAtIndexPath:(NSIndexPath*)indexPath
{
    if (indexPath.row== 0) {
        [self_countCacheSize];
        UILabel *label = (UILabel*)[cell viewWithTag:100];
        label.text= [NSStringstringWithFormat:@"%.1fM",cacheSize];
    }

}

- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath
{
    if (indexPath.row== 0) {
        //弹出清除对话框
        UIAlertController *alertCtrl = [UIAlertControlleralertControllerWithTitle:@"清空缓存"message:@"确定要清空缓存"preferredStyle:UIAlertControllerStyleAlert];
       
        UIAlertAction *cancleAction = [UIAlertActionactionWithTitle:@"取消"style:UIAlertActionStyleCancelhandler:nil];
       
        UIAlertAction *sureAction = [UIAlertActionactionWithTitle:@"确定"style:UIAlertActionStyleDefaulthandler:^(UIAlertAction*action) {
            //确定清空缓存

            [[SDImageCachesharedImageCache] clearDisk];

           
            //刷新tableView
            [self.tableViewreloadData];
           
        }];
       
        [alertCtrl addAction:cancleAction];
        [alertCtrl addAction:sureAction];
        [selfpresentViewController:alertCtrlanimated:YEScompletion:nil];
    }

}

- (void)viewWillAppear:(BOOL)animated
{
    [superviewWillAppear:animated];
    //刷新tableView
    [self.tableViewreloadData];

}

18.label宽度自适应

- (CGSize)labelAutoCalculateRectWith:(NSString*)text FontSize:(CGFloat)fontSize MaxSize:(CGSize)maxSize
{
   
    NSMutableParagraphStyle* paragraphStyle = [[NSMutableParagraphStylealloc]init];
   
    paragraphStyle.lineBreakMode= NSLineBreakByWordWrapping;
   
    NSDictionary* attributes =@{NSFontAttributeName:[UIFontsystemFontOfSize:fontSize],NSParagraphStyleAttributeName:paragraphStyle.copy};
   
    CGSize labelSize = [textboundingRectWithSize:maxSizeoptions:NSStringDrawingUsesLineFragmentOrigin| NSStringDrawingUsesFontLeading | NSStringDrawingTruncatesLastVisibleLineattributes:attributescontext:nil].size;
   
    labelSize.height= ceil(labelSize.height);
   
    labelSize.width= ceil(labelSize.width);
   
    return labelSize;
   

}