IOS笔记

//应用程序目录

1 /Documents   2. /Library/Caches   3. /Library/Preferences   4. /tmp

//获取应用版本号

NSString *version = [[[NSBundlemainBundle]infoDictionary]objectForKey:@"CFBundleVersion"];

//判断对象是否为指定类型

[(id)object  isKindOfClass  [(id)object  class];

//判断设备类型

-(NSString*) getDeviceVersion{

    //方法1：判断所有设备

    if (0) {

        size_t size;

        sysctlbyname("hw.machine",NULL,&size,NULL,0);

        char *machine = (char*) malloc(size);

        sysctlbyname("hw.machine",machine,&size,NULL,0);

        NSString *platform = [NSString stringWithCString:machine encoding:NSUTF8StringEncoding];

        free(machine);

return platform;

    }

    //方法2 判断是iphone4还是iphone5

    CGRect rect = [[UIScreenmainScreen]bounds];

    if (rect.size.height ==1136 || rect.size.height ==568) {

        return @"iphone5";

    }else{

        return @"iphone4";

    }

}

分辨率：

CGRect rect = [[UIScreenmainScreen]bounds];

CGFloat scale = [UIScreen mainScreen].scale;

NSString *model = [UIDevice currentDevice].model

retaincount 的理解

http://blog.csdn.net/andypan1314/article/details/7055237

有关@property与retaincount

@property test* the test     retaincount 从来不加1

@property(retain)test* thetest  当被调用时retaincount加1

@property(nonatomic,retain)test* thetest  当被赋值时retaincount加1

URL请求：

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"];

NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

图片数据旋转： UIImage *changeImage = [[UIImage imageWithCGImage:image01.CGImage scale:1.0 orientation: UIImageOrientationRight];

路径：

资源包路径：

NSString* resourcePath = [[NSBundlemainBundle] resourcePath];

获取Documents文件路径：

NSString* filePath = NSHomeDirectory();

NSString *DocumentsPath = [filePath stringByAppendingPathComponent:@"Documents"];

NSArray *pathsArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsPath = [pathsArray objectAtIndex:0];

绝对路径、相对路径：

NSString *path = @"~/aaa.txt";

NSString *absolutePath = [Path stringByExpendingTildeInPath];

NSString *relativePath = [absolutePath stringByAbbreviatingWithTildeInPath];

文件：

创建文件：

[[NSFileManager defaultManager] createFileAtPath:filePath];

创建文件夹：

[[NSFileManager defaultManager] createDirectoryAtPath:folerPath ......];

判断文件是否存在：

[[NSFileManager defaultManager] fileExistsAtPath:filePath];

删除文件（文件夹）：

[[NSFileManager defaultManager] removeItemAtPath:filePath];