IOS 擷取文本的高度和寬度__IOS

+ (CGFloat)heightForContent:(MyMsgTextModel *)content withWidth:(CGFloat)width{    CGSize contentSize;    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {        NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];        paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;//        NSDictionary *attributes = @{NSFontAttributeName:CELL_CONTENT_FONT_SIZE, NSParagraphStyleAttributeName:paragraphStyle.copy};        NSDictionary *attributes = @{NSFontAttributeName:CELL_CONTENT_FONT_SIZE};                contentSize = [content.textMsg boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:attributes context:nil].size;    }    else{        contentSize = [content.textMsg sizeWithFont:CELL_CONTENT_FONT_SIZE                              constrainedToSize:CGSizeMake(width, CGFLOAT_MAX)                                  lineBreakMode:NSLineBreakByWordWrapping];    }        return contentSize.height;}

2. autolayout中一直確定不了裝置的高度和寬度

可以使用 layoutSubviews, 但是這個方法會被調用多次, 所以這個方法裡只能用於控制frame

3. sizeToFit

這個方法是讓uiview 根據子視圖 來確定size

常用與UIlabel, 根據文本來確定UILabel的size

 

3. - (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:

讓uiimageview left和top方向某個範圍內不被展開, 用於做氣泡