NSMutableParagraphStyle ／NSParagraphStyle

//   NSParagraphStyleAttributeName 段落的風格（設置首行，行間距，對齊方式什麼的）看本身須要什麼屬性，寫什麼  
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];  
    paragraphStyle.lineSpacing = 10;// 字體的行間距  
    paragraphStyle.firstLineHeadIndent = 20.0f;//首行縮進  
    paragraphStyle.alignment = NSTextAlignmentJustified;//（兩端對齊的）文本對齊方式：（左，中，右，兩端對齊，天然）  
    paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;//結尾部分的內容以……方式省略 ( "...wxyz" ,"abcd..." ,"ab...yz")  
    paragraphStyle.headIndent = 20;//總體縮進(首行除外)  
    paragraphStyle.tailIndent = 20;//  
    paragraphStyle.minimumLineHeight = 10;//最低行高  
    paragraphStyle.maximumLineHeight = 20;//最大行高  
    paragraphStyle.paragraphSpacing = 15;//段與段之間的間距  
    paragraphStyle.paragraphSpacingBefore = 22.0f;// 段首行空白空間 /* Distance between the bottom of the previous paragraph (or the end of its paragraphSpacing, if any) and the top of this paragraph. */  
    paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight;//從左到右的書寫方向（一共➡️三種）  
    paragraphStyle.lineHeightMultiple = 15;/* Natural line height is multiplied by this factor (if positive) before being constrained by minimum and maximum line height. */  
    paragraphStyle.hyphenationFactor = 1;//連字屬性 在iOS，惟一支持的值分別爲0和1  
 
/* 
     NSFontAttributeName 字體大小 
     NSParagraphStyleAttributeName 段落的風格（設置首行，行間距，對齊方式什麼的） 
     NSKernAttributeName 字間距 
     */  
    NSDictionary *attributes = @{  
                                 NSFontAttributeName:[UIFont systemFontOfSize:15],  
                                 NSParagraphStyleAttributeName:paragraphStyle,  
                                 NSKernAttributeName:@(10),  
                                                                
                                 };  
    textView.attributedText = [[NSAttributedString alloc] initWithString:textView.text attributes:attributes];