UIlabel多行文字自动换行 （自动折行）

UIView *footerView = [[UIView alloc]initWithFrame:CGRectMake(10, 100, 300, 180)]; UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(10, 100, 300, 150)]; label.text = @"Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Helloworld!";
 // 背景颜色为红色 
label.backgroundColor = [UIColor redColor]; 
// 设置字体颜色为白色 
label.textColor = [UIColor whiteColor];
// 文字居中显示 
label.textAlignment = UITextAlignmentCenter;
// 自动折行设置
label.lineBreakMode = UILineBreakModeWordWrap; 
label.numberOfLines = 0;