iOS 按钮设置图片和事件

[btn addTarget:self action:@selector(searchButtonClick) forControlEvents:UIControlEventTouchUpInside];

[btn setImage:[UIImage imageNamed:@"Icon"] forState:UIControlStateNormal];

[btn setImage:[UIImage imageNamed:@"Icon"] forState:UIControlStateSelected];

原文：http://www.cnblogs.com/SimonGao/p/5051429.html