iOS 根据文字字数动态确定Label宽高

iOS7中用以下方法

- (CGSize)sizeWithAttributes:(NSDictionary *)attrs;

替代过时的iOS6中的- (CGSize)sizeWithFont:(UIFont *)font 方法

    // iOS7_API_根据文字 字数动态确定Label宽高

    // 设置Label的字体 HelveticaNeue  Courier

    UIFont *fnt = [UIFont fontWithName:@"HelveticaNeue" size:24.0f];

    _nameLabel.font = fnt;

    // 根据字体得到NSString的尺寸

    CGSize size = [_nameLabel.text sizeWithAttributes:[NSDictionary dictionaryWithObjectsAndKeys:fnt,NSFontAttributeName, nil]];

    // 名字的H

    CGFloat nameH = size.height;

    // 名字的W

    CGFloat nameW = size.width;

    _nameLabel.frame = CGRectMake(0, 0, nameW,nameH);

iOS7中用以下方法boundingRectWithSize:options:attributes:context:替代过时的iOS6中的sizeWithFont:constrainedToSize:lineBreakMode:方法

// 4,根据正文内容多少,动态确定正文content的frame

    // 宽度W

    CGFloat contentW = self.bounds.size.width - _content.frame.origin.x - kMargin;

    // label的字体 HelveticaNeue  Courier

    UIFont *fnt = [UIFont fontWithName:@"HelveticaNeue" size:18.0f];

    _content.font = fnt;

    _content.numberOfLines = 0;

    _content.lineBreakMode = NSLineBreakByWordWrapping;

    // iOS7中用以下方法替代过时的iOS6中的sizeWithFont:constrainedToSize:lineBreakMode:方法

    CGRect tmpRect = [_content.text boundingRectWithSize:CGSizeMake(contentW, 1000) options:NSStringDrawingUsesLineFragmentOrigin attributes:[NSDictionary dictionaryWithObjectsAndKeys:fnt,NSFontAttributeName, nil] context:nil];

    // 高度H

    CGFloat contentH = tmpRect.size.height;

    NSLog(@"调整后的显示宽度:%f,显示高度:%f"contentW,contentH);

    _content.frame = CGRectMake(0, 0, contentW,contentH);

附:API文档参考

boundingRectWithSize:options:attributes:context:

Calculates and returns the bounding rect for the receiver drawn using the given options and display characteristics, within the specified rectangle in the current graphics context.

- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes context:(NSStringDrawingContext *)context

Parameters

size

The size of the rectangle to draw in.

options

String drawing options.

attributes

A dictionary of text attributes to be applied to the string. These are the same attributes that can be applied to anNSAttributedString object, but in the case ofNSString objects, the attributes apply to the entire string, rather than ranges within the string.

context

The string drawing context to use for the receiver, specifying minimum scale factor and tracking adjustments.

Return Value

The bounding rect for the receiver drawn using the given options and display characteristics. The rect origin returned from this method is the first glyph origin.

Discussion

To correctly draw and size multi-line text, pass NSStringDrawingUsesLineFragmentOrigin in the options parameter.

This method returns fractional sizes (in the size component of the returnedCGRect); to use a returned size to size views, you must raise its value to the nearest higher integer using theceil function.

This method returns the actual bounds of the glyphs in the string. Some of the glyphs (spaces, for example) are allowed to overlap the layout constraints specified by the size passed in, so in some cases the width value of the size component of the returned CGRect can exceed the width value of the size parameter.

Availability

Available in iOS 7.0 and later.

See Also

– drawInRect:withAttributes:

Declared In

NSStringDrawing.h

巴特西

iOS 根据文字字数动态确定Label宽高

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