iOS开发基础之UILabel控件的用法

//根据frame创建
UILabel *label1 = [[UILabel alloc] initWithFrame:CGRectMake(50,50,200,200)];
//文本内容
label1.text = @"自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行自动换行";
//label1背景颜色
label1.backgroundColor = [UIColor redColor];
//文本颜色
label1.textColor = [UIColor yellowColor];
//设置字体格式
label1.font = [UIFont systemFontOfSize:25];//字体大小，默认17
label1.font = [UIFont boldSystemFontOfSize:25.0];//字体粗细
//设置label行数，默认为0自动换行
label1.numberOfLines = 0;
//设置对齐方式
label1.textAlignment = NSTextAlignmentRight;//右对齐
label1. label1.textAlignment = NSTextAlignmentLeft;//左对齐
label1.textAlignment = NSTextAlignmentCenter;//居中对齐
//截取部分以省略号代替
label1.lineBreakMode = NSLineBreakByTruncatingHead//...abc省略头部
label1.lineBreakMode = NSLineBreakByTruncationMiddle//abc...hij省略中间部分
label1.lineBreakMode = NSLineByTruncatingTail//abcde....省略尾部
//添加到视图
[self.view addSubview:label1];

//文字字体的自动缩放，可以根据label的大小，文字自动缩放以适合视图
UILabel *label2 = [[UILabel alloc]initWithFrame:CGRectMake(50, 50,200, 200)];
label2.backgroundColor = [UIColor blackColor];
label2.textColor = [UIColor whiteColor];
label2.text = @"自动缩放";
//自动换行
//自动换行
label2.numberOfLines = 0;
label2.font = [UIFont systemFontOfSize:30];
//自动调整字体大小
label2.adjustsFontSizeToFitWidth = YES;
//设置字体缩放的下限
label2.minimumScaleFactor = 0.8;//0.8*30
[self.view addSubview:label2];

//自适应高度
UILabel *label3 = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 200)];
label3.text = @"自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度自适应高度";
label3.backgroundColor = [UIColor blackColor];
label3.textColor = [UIColor whiteColor];

[self.view addSubview:label3];

/长文本自适应
CGRect rect = [label3.text boundingRectWithSize:CGSizeMake(300, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:label3.font} context:nil];

label3.frame = CGRectMake(50, 50, 300, rect.size.height);
label3.numberOfLines = 0;
_label = label3;

//短文本自适应
UILabel *label4 = [[UILabel alloc] init];
label4.text = @"还有半个小时下课";
label4.backgroundColor = [UIColor blackColor];
[label4 setTextColor:[UIColor whiteColor]];

CGSize size = [label4.text sizeWithAttributes:@{NSFontAttributeName:label4.font}];

label4.frame = CGRectMake(0, 0, size.width, size.height);
[self.view addSubview:label4];