简短实用的Objective-C片段？

// 创建一个UILabel并设置属性
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 200, 50)];
label.text = @"Hello World";
label.textColor = [UIColor blackColor];
label.textAlignment = NSTextAlignmentCenter;
label.font = [UIFont systemFontOfSize:20.0];

// 将UILabel添加到视图中
[self.view addSubview:label];