iphone document 图片存储和读取

存：

  //此处首先指定了图片存取路径（默认写到应用程序沙盒 中）
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    
    //并给文件起个文件名
    NSString *uniquePath=[[paths objectAtIndex:0] stringByAppendingPathComponent:@"pin.png"];
    BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:uniquePath];
    if (blHave) {
        NSLog(@"already have");
        return ;
    }
    //此处的方法是将图片写到Documents文件中 如果写入成功会弹出一个警告框,提示图片保存成功
    NSString *strPathOld = [[NSBundle mainBundle] pathForResource:@"pin" ofType:@"png"];
    NSData *data = [NSData dataWithContentsOfFile:strPathOld];
    BOOL result = [data writeToFile:uniquePath atomically:YES];
    if (result) {
        NSLog(@"success");
    }else {
        NSLog(@"no success");
    }
 

取：

  NSFileManager *fileManager = [NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory,                                                                          NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *filePath2 = [documentsDirectory stringByAppendingPathComponent:@"pin.png"];
    UIImage *img = [UIImage imageWithContentsOfFile:filePath2];
    [image setImage:img];
    NSLog(@"图片：：：：：：：：：%@",image.image);
 

删：

 NSFileManager* fileManager=[NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    
    //文件名
    NSString *uniquePath=[[paths objectAtIndex:0] stringByAppendingPathComponent:@"pin.png"];
    BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:uniquePath];
    if (!blHave) {
        NSLog(@"no  have");
        return ;
    }else {
        NSLog(@" have");
        BOOL blDele= [fileManager removeItemAtPath:uniquePath error:nil];
        if (blDele) {
            NSLog(@"dele success");
        }else {
            NSLog(@"dele fail");
        }
        
    }