为什么不显示此图像？ 使用NSData和initWithData

Question

NSURL* urlEx = [NSURL URLWithString:@"Pacific_Map.png"];
NSData* mapExIMGData = [[NSData alloc] initWithContentsOfURL: urlEx];

UIImage* imgEx = [[UIImage alloc] initWithData:mapExIMGData];

mapImageViewEx.image = imgEx;

If I replace mapImageViewEx.image = imgEx; with mapImageViewEx.image = [UIImage imageNamed:@"Pacific_Map.png"]; it works, but I do not want to use imageNamed.

Answer 1

That's because imageNamed knows where to scan for the file, but initWithContentsOfURL expects the full path. use

NSString *imagePath = [[NSBundle mainBundle] pathForResource:@"Pacific_Map" ofType:@"png"];
NSURL* urlEx = [NSURL fileURLWithPath:imagePath];
NSData* mapExIMGData = [[NSData alloc] initWithContentsOfURL: urlEx];

UIImage* imgEx = [[UIImage alloc] initWithData:mapExIMGData];

mapImageViewEx.image = imgEx;

Answer 2

What's wrong with using imageNamed? Anyway, you could use initWithContentsofPath.

+ (UIImage *)imageWithContentsOfFile:(NSString *)path

Tell us more about what you are trying to accomplish. Good luck,

James

EDIT: Sorry, I assumed Pacific_Map.png was just a placeholder path. Like someone else posted, you need to indicate the full path if you're not going to use imageNamed.