控制UIlabel 垂直方向对齐方式的 方法

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// -- file: UILabel+VerticalAlign.h

#pragma mark VerticalAlign

@interface UILabel (VerticalAlign)

- (void)alignTop;

- (void)alignBottom;

@end

// -- file: UILabel+VerticalAlign.m

@implementation UILabel (VerticalAlign)

- (void)alignTop {

    CGSize fontSize = [self.text sizeWithFont:self.font];

    double finalHeight = fontSize.height * self.numberOfLines;

    double finalWidth = self.frame.size.width;    //expected width of label

    CGSize theStringSize = [self.text sizeWithFont:self.font constrainedToSize:CGSizeMake(finalWidth, finalHeight) lineBreakMode:self.lineBreakMode];

    int newLinesToPad = (finalHeight  - theStringSize.height) / fontSize.height;

    for(int i=0; i<newLinesToPad; i++)

        self.text = [self.text stringByAppendingString:@"\n "];

}

- (void)alignBottom {

    CGSize fontSize = [self.text sizeWithFont:self.font];

    double finalHeight = fontSize.height * self.numberOfLines;

    double finalWidth = self.frame.size.width;    //expected width of label

    CGSize theStringSize = [self.text sizeWithFont:self.font constrainedToSize:CGSizeMake(finalWidth, finalHeight) lineBreakMode:self.lineBreakMode];

    int newLinesToPad = (finalHeight  - theStringSize.height) / fontSize.height;

    for(int i=0; i<newLinesToPad; i++)

        self.text = [NSString stringWithFormat:@" \n%@",self.text];

}

@end