Android示例蓝牙代码通过蓝牙发送简单的字符串

I want to send a simple string data such as 'a' from an android device to other one via bluetooth. I looked sample bluetooth code in android sdk but it is so complex for me. I cannot understand how I can send only specific data when I press a button. How can I solve this problem? I want to send a simple string data such as 'a'