1.新建一個字符串的類別

#import NSString (Extension)

- (CGSize)sizeWithFont:(UIFont *)font maxSize:(CGSize)maxSize;

@end

@implementation NSString (Extension)

#pragma mark 計算字符串大小

- (CGSize)sizeWithFont:(UIFont *)font maxSize:(CGSize)maxSize

{

NSDictionary *dict = @{NSFontAttributeName: font};

CGSize textSize = [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:dict context:nil].size;

return textSize;

}

2.如何使用

NSString *tempStr = @"《肖申克的救贖》里有一句臺詞：剛入獄的時候，你痛恨周圍的高墻；慢慢地，你習慣了生活在其中；最終你會發(fā)現(xiàn)自己不得不依靠它而生存。這就叫體制化";

//(控件寬度)

CGFloat textW = txtWidth;

//文字高度

CGFloat textH = [txtAnswers sizeWithFont:[UIFont systemFontOfSize:14] maxSize:CGSizeMake(textW, MAXFLOAT)].height;

//最后設置numberOfLines = 0;