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UILabel實現上下左右內邊距和自適用高度的計算三種方法

顯示 str number 控件 -s limited rgb return set

1、由於label控件沒有contentInsets屬性,需要自定義label,添加Insets 屬性,並重寫父類的幾個方法

//下面四個方法用來初始化edgeInsets

- (instancetype)init {

if (self = [super init]) {

self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);

}

return self;

}

- (instancetype)initWithFrame:(CGRect)frame

{

if(self = [super initWithFrame:frame])

{

self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);

}

return self;

}

//storyboard使用

- (instancetype)initWithCoder:(NSCoder *)aDecoder

{

if (self = [super initWithCoder:aDecoder]) {

self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);

}

return self;

}

//xib使用

- (void)awakeFromNib

{

[super awakeFromNib];

self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);

}

// 修改繪制文字的區域,edgeInsets增加bounds

-(CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines

{

//設置第一行和最後一行距離label的距離

CGRect rect = [super textRectForBounds:UIEdgeInsetsInsetRect(bounds,self.edgeInsets) limitedToNumberOfLines:numberOfLines];

//根據edgeInsets,修改繪制文字的bounds

rect.origin.x -= self.edgeInsets.left;

rect.origin.y -= self.edgeInsets.top;

rect.size.width += self.edgeInsets.left + self.edgeInsets.right;

rect.size.height += self.edgeInsets.top + self.edgeInsets.bottom;

return rect;

}

//繪制文字

- (void)drawTextInRect:(CGRect)rect

{

//令繪制區域為原始區域,增加的內邊距區域不繪制

[super drawTextInRect:UIEdgeInsetsInsetRect(rect, self.edgeInsets)];

}

2、label控件顯示多行文本,需要設置numberOfLines設置為0,還要自適用高度

//第一種方法:

self.label.adjustsFontSizeToFitWidth=YES;

//第二種方法:(廢棄API)

CGFloat fontSizeToFits;

[self.label.text sizeWithFont:self.label.font minFontSize:12.0 actualFontSize:&fontSizeToFits forWidth:self.label.bounds.size.width lineBreakMode:NSLineBreakByWordWrapping];//12是最小字體

self.label.font = [self.label.font fontWithSize:fontSizeToFits];

//第三種方法:

CGSize labelSize = [self.text boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width - 20, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14]} context:nil].size;

self.label.frame = CGRectMake(0, 0, labelSize.width, labelSize.height);

UILabel實現上下左右內邊距和自適用高度的計算三種方法