UILabel的使用

创建项目

创建一个单视图项目，如下布局：

五个VIEW，五等份屏幕宽度，高度为120。五个UI Label，大小同view。

设置UI Label文字

- (void)viewDidLoad {    [super viewDidLoad];    NSString *text = @"话说天下大势，分久必合，合久必分：周末七国分争，并入于秦；及秦灭之后，楚、汉分争，又并入于汉；汉朝自高祖斩白蛇而起义，一统天下，后来光武中兴，传至献帝，遂分为三国。推其致乱之由，殆始于桓、灵二帝。桓帝禁锢善类，崇信宦官。及桓帝崩，灵帝即位，大将军窦武、太傅陈蕃共相辅佐。时有宦官曹节等弄权，窦武、陈蕃谋诛之，机事不密，反为所害。中涓自此愈横。";    self.lab1.text = text;    self.lab2.text = text;    self.lab3.text = text;    self.lab4.text = text;    self.lab5.text = text;}

效果：

这里除了文字，没有做任何设置。

多行文字显示

多行文字显示的关键属性：

@property(nonatomic) NSInteger numberOfLines;@property(nonatomic) NSLineBreakMode  lineBreakMode;

具体代码：

    self.lab1.numberOfLines = 0;    self.lab2.numberOfLines = 0;    self.lab3.numberOfLines = 0;    self.lab4.numberOfLines = 0;    self.lab5.numberOfLines = 0;    self.lab6.numberOfLines = 0;    self.lab1.lineBreakMode = NSLineBreakByWordWrapping;    self.lab2.lineBreakMode = NSLineBreakByCharWrapping;    self.lab3.lineBreakMode = NSLineBreakByClipping;    self.lab4.lineBreakMode = NSLineBreakByTruncatingHead;    self.lab5.lineBreakMode = NSLineBreakByTruncatingTail;    self.lab6.lineBreakMode = NSLineBreakByTruncatingMiddle;self.lab1.textColor = [UIColor blueColor];self.lab2.textColor = [UIColor blueColor];self.lab3.textColor = [UIColor blueColor];self.lab4.textColor = [UIColor blueColor];self.lab5.textColor = [UIColor blueColor];self.lab6.textColor = [UIColor blueColor];self.lab1.font = [UIFont systemFontOfSize:14];self.lab2.font = [UIFont systemFontOfSize:14];self.lab3.font = [UIFont systemFontOfSize:14];self.lab4.font = [UIFont systemFontOfSize:14];self.lab5.font = [UIFont systemFontOfSize:14];self.lab6.font = [UIFont systemFontOfSize:14];

numberOfLines属性为多行文字显示的最关键属性，必须设置为0，才能进行多行显示。
lineBreakMode属性则负责文字过多，label内无法完全显示时候的不同处理。共有六种不同的取值，如下：

// NSParagraphStyletypedef NS_ENUM(NSInteger, NSLineBreakMode) {    NSLineBreakByWordWrapping = 0,      // Wrap at word boundaries, default    NSLineBreakByCharWrapping,      // Wrap at character boundaries    NSLineBreakByClipping,      // Simply clip    NSLineBreakByTruncatingHead,    // Truncate at head of line: "...wxyz"    NSLineBreakByTruncatingTail,    // Truncate at tail of line: "abcd..."    NSLineBreakByTruncatingMiddle   // Truncate middle of line:  "ab...yz"} NS_ENUM_AVAILABLE(10_0, 6_0);

下图中，前六个label分别使用了六种不同的值。

Label添加边框

self.lab7.layer.borderColor = [[UIColor redColor] CGColor];self.lab7.layer.borderWidth = 2;