Question

当我将NSMutableArray转换为NSdata时，我以字节为单位获取NSMutableArray数据。现在我想把它转换成UIImage，因为我想通过电子邮件发送My Array数据，但是我在UIImage中得到了null。

这是我的代码。

     NSData *data = [NSKeyedArchiver archivedDataWithRootObject:viewArray];
      UIImage *image = [UIImage imageWithData:data];
      [controller addAttachmentData:image mimeType:@"image/png"
             fileName:@"labelData"];

Answer 1

要将图像转换为字符串，您需要一种方法将NSData转换为base64Encoded字符串并返回（许多示例http://cocoadev.com/wiki/BaseSixtyFour）。最容易使用的是NSData上的类别，因此您可以执行以下操作：

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:viewArray];
NSString* pictureDataString = [self base64EncodingWithLineLength:data];
UIImage* image = [UIImage imageWithData:[NSData 
        dataFromBase64EncodedString: pictureDataString]];
[controller addAttachmentData:image mimeType:@"image/png"
         fileName:@"labelData"];


- (NSString *) base64EncodingWithLineLength:(NSData*) data {

const unsigned char* bytesArr=[data bytes];
unsigned int lineLength=0;
NSMutableString *result = [NSMutableString stringWithCapacity:[data length]];
unsigned long ixtext = 0;
unsigned long lentext = [data length];
long ctremaining = 0;
unsigned char inbuf[3], outbuf[4];
unsigned short i = 0;
unsigned short charsonline = 0, ctcopy = 0;
unsigned long ix = 0;

while( YES ) {
    ctremaining = lentext - ixtext;
    if( ctremaining <= 0 ) break;

    for( i = 0; i < 3; i++ ) {
        ix = ixtext + i;
        if( ix < lentext ) inbuf[i] = bytesArr[ix];
        else inbuf [i] = 0;
    }

    outbuf [0] = (inbuf [0] & 0xFC) >> 2;
    outbuf [1] = ((inbuf [0] & 0x03) << 4) | ((inbuf [1] & 0xF0) >> 4);
    outbuf [2] = ((inbuf [1] & 0x0F) << 2) | ((inbuf [2] & 0xC0) >> 6);
    outbuf [3] = inbuf [2] & 0x3F;
    ctcopy = 4;

    switch( ctremaining ) {
        case 1:
            ctcopy = 2;
            break;
        case 2:
            ctcopy = 3;
            break;
    }

    for( i = 0; i < ctcopy; i++ )
        [result appendFormat:@"%c", encodingTable[outbuf[i]]];

    for( i = ctcopy; i < 4; i++ )
        [result appendString:@"="];

    ixtext += 3;
    charsonline += 4;

    if( lineLength > 0 ) {
        if( charsonline >= lineLength ) {
            charsonline = 0;
            [result appendString:@"\n"];
        }
    }
}

return [NSString stringWithString:result];
}




static char encodingTable[64] = {
'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/' };

尝试这种方式可能会帮助你。

将字节转换为UIImage

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