Question

以下代码不显示从在线下载并写入我的应用程序文档目录的图像。我已经检查了iphone的模拟器文件目录，下载的文件是否存在。但图像不显示。

尝试使用UIImage *imgBack = [UIImage imageNamed:@"btn-back.png"];添加资源图像时，uiimageview会显示image.bu，从在线下载并存储在app目录中的图像不会显示图像。

请告诉我并感谢

NSString *workSpacePath=[[self applicationDocumentsDirectory] stringByAppendingPathComponent:theFileName];
NSLog(@"%@ workSpacePath ",workSpacePath);
if ( workSpacePath ){

        //--------------
       UIImage *imgBack = [UIImage imageNamed:@"btn-back.png"];
       imageView1 = [[[UIImageView alloc] initWithFrame:CGRectMake(0,0,20,20)] autorelease];
       [imageView1 setBackgroundColor:[UIColor grayColor]];

       imageView1.image = [UIImage imageWithData:[NSData dataWithContentsOfFile:workSpacePath]];
       [cell addSubview:imageView1];
}

Answer 1

您可以使用

，而不是先将文件转换为NSData

[UIImage imageWithContentsOfFile:filePath]

直接加载具有指定路径的image。

Answer 2

试试这个，这对我来说非常有用：

 - (void)viewDidLoad
{
     [super viewDidLoad];

     NSURL *url1 = [NSURL URLWithString:@"http://mobiledevelopertips.com/images/logo-iphone-dev-tips.png"];
    UIImage *image = [UIImage imageWithData: [NSData dataWithContentsOfURL:url1]];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,     NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:@"savedImage.png"];

    NSData *imageData = UIImagePNGRepresentation(image);
    [imageData writeToFile:savedImagePath atomically:NO]; 

    NSArray *paths1 = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory1 = [paths1 objectAtIndex:0];
    NSString *workSpacePath = [documentsDirectory1 stringByAppendingPathComponent:@"savedImage.png"]; 
    NSLog(@"%@ workSpacePath ",workSpacePath);

if ( workSpacePath )
     {
        imageView1 = [[UIImageView alloc] initWithFrame:CGRectMake(20,20,20,20)];
        [imageView1 setBackgroundColor:[UIColor grayColor]];

        imageView1.image = [UIImage imageWithData:[NSData dataWithContentsOfFile:workSpacePath]];
        [self.view addSubview:imageView1];

    }
}

使用UIImage imageWithData：NSData dataWithContentsOfFile时未显示图像

2 个答案: