Question

我的字符串中有一些字节的图像，我想将它绘制到UIImageView ...这是我的代码

NSString* str= @"<89504e47 0d0a1a0a 0000000d 49484452 ........... 454e44ae 426082>";
    NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding]; 
    NSLog(@"My NSDATA  %@",data);
    imageView.image=[UIImage imageWithData:data];

现在，当我在控制台上看到打印数据时，它与我给该字符串的格式不同。输出类似......

<3c383935 30346534 37203064 30613161..........

所以我的imageview什么都没显示.....请帮忙

Answer 1

如果问题是：如何将字符串数据转换为图像，那么这就是答案。

NSData *imgData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"icon" ofType:@"png"]];
// set your string data into inputString var
NSString *inputString = [imgData description];
NSLog(@"input string  %@",inputString);
// clearing string from trashes
NSString *dataStr = [inputString stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]];
// separate by words of 4 bytes
NSArray *words = [dataStr componentsSeparatedByString:@" "];
// calculate number of bytes
NSArray *sizes = [words valueForKey:@"length"];
int sizeOfBytes = 0;
for (NSNumber *size in sizes) {
    sizeOfBytes += [size intValue]/2;
}
int bytes[sizeOfBytes];
int counts = 0;
for (NSString *word in words) {
    // convert each word from string to int
    NSMutableString *ostr = [NSMutableString stringWithCapacity:[word length]];
    while ([word length] > 0) {
        [ostr appendFormat:@"%@", [word substringFromIndex:[word length] - 2]];
        word = [word substringToIndex:[word length] - 2];
    }

    NSScanner *scaner = [NSScanner scannerWithString:ostr];
    unsigned int val;
    [scaner scanHexInt:&val];
    bytes[counts] = val;
    counts++;
}
// get NSData form c array
NSData* data = [NSData dataWithBytes:bytes length:sizeOfBytes];
NSLog(@"My NSDATA  %@",data);
// your image is ready
UIImage *image = [UIImage imageWithData:data];
NSLog(@"image: %@",image);

Answer 2

您在NSLog输出中看到的是字符串字符的ASCII代码。例如：

NSString* str = @"A";
NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding]; 
NSLog(@"%@",data);

你会看到类似的东西：

＆LT; 41 ...

那是因为0x41是字母A的代码。

你的字符串也是如此。

Answer 3

数据正好你正在提供它：一个简单的字符串（打印为原始字节值）。但我猜你的输入字符串是一个hexdump，你手动需要变成字节。

NSString到NSData转换问题

3 个答案: