頂部垂直文本部分對齊的UILabel

Question

我們怎樣才能繼承的標籤，以便它顯示的文字如下 前綴（對齊頂部），文本和，後綴（對齊底部）。

我已經目前使用上的UILabel

-(void)setText:(id)text withPrefixText:(id)prefixText andSuffixText:(id)suffixText { 

    NSString * compondText = [self textByCompoundingText:text withPrefixText:prefixText WithsuffixText:suffixText]; 
    NSMutableAttributedString * attributedCompoundText = [[NSMutableAttributedString alloc] initWithString:compondText]; 

    NSMutableDictionary * prefixTextAttributes = [@{} mutableCopy]; 
    prefixTextAttributes[NSFontAttributeName] = _prefixTextFont? _prefixTextFont:self.font; 
    prefixTextAttributes[NSForegroundColorAttributeName] = _prefixTextColour? _prefixTextColour:self.textColor; 
    prefixTextAttributes[(NSString*)kCTSuperscriptAttributeName] = [NSNumber numberWithUnsignedInteger:_prefixTextVerticalPositionning]; 

    NSMutableDictionary * suffixTextAttributes = [@{} mutableCopy]; 
    suffixTextAttributes[NSFontAttributeName] = _suffixTextFont? _suffixTextFont:self.font; 
    suffixTextAttributes[NSForegroundColorAttributeName] = _suffixTextColour ?_suffixTextColour:self.textColor; 
    suffixTextAttributes[(NSString*)kCTSuperscriptAttributeName] = [NSNumber numberWithUnsignedInteger:_suffixTextVerticalPostioning]; 

    if(prefixText) 
     [attributedCompoundText addAttributes:prefixTextAttributes range:[compondText rangeOfString:prefixText]]; 
    if(suffixText) 
     [attributedCompoundText addAttributes:suffixTextAttributes range:[compondText rangeOfString:suffixText]]; 

    self.attributedText = attributedCompoundText; 
} 

的子類下面的方法，但這種設置文本爲上標不解決問題。前綴文本和文本的頂部應該相同，但前綴文本應該垂直頂部與較小的字體對齊！

Answer 1

使用NSBaselineOffsetAttributeName解決我的問題，利用這個我們可以指定從底部的偏移。+已經對標和-ve爲下標

-(void)setText:(id)text withPrefixText:(id)prefixText andSuffixText:(id)suffixText 
    { 
    NSString * compondText = [self textByCompoundingText:text withPrefixText:prefixText  WithsuffixText:suffixText]; 
NSMutableAttributedString * attributedCompoundText = [[NSMutableAttributedString alloc] initWithString:compondText]; 

NSMutableDictionary * prefixTextAttributes = [@{} mutableCopy]; 
prefixTextAttributes[NSFontAttributeName] = _prefixTextFont? _prefixTextFont:self.font; 
prefixTextAttributes[NSForegroundColorAttributeName] = _prefixTextColour? _prefixTextColour:self.textColor; 
NSNumber *baselineOffSet =[NSNumber numberWithUnsignedInteger:_prefixTextVerticalPositionning]; 
prefixTextAttributes[(NSString*)NSBaselineOffsetAttributeName] = baselineOffSet; 

NSMutableDictionary * suffixTextAttributes = [@{} mutableCopy]; 
suffixTextAttributes[NSFontAttributeName] = _suffixTextFont? _suffixTextFont:self.font; 
suffixTextAttributes[NSForegroundColorAttributeName] = _suffixTextColour ?_suffixTextColour:self.textColor; 
baselineOffSet = [NSNumber numberWithUnsignedInteger:_suffixTextVerticalPostioning]; 
suffixTextAttributes[(NSString*)NSBaselineOffsetAttributeName] = baselineOffSet; 

if(prefixText) 
    [attributedCompoundText addAttributes:prefixTextAttributes range:[compondText rangeOfString:prefixText]]; 
if(suffixText) 
    [attributedCompoundText addAttributes:suffixTextAttributes range:[compondText rangeOfString:suffixText]]; 

self.attributedText = attributedCompoundText; 

}