原來把findViewById的動作移到了 setContentView(R.layout.main);之前
在Android如果在使用setContentView把顯示元件創造出來之前
findViewById是找不到任何東西的,所以必須把findViewById的動作放到setContentView之後
所以如果写程序必须先把基础的view添加好setContentView后才能做检索,否则根本不可能使用R.layout.main,感觉google这么干也就是想用layout的main.xml做基础的构架,以我目前的理解,不知道动态动态生成的View是否可以使用R.java进行检索的。
*)if you run the Android app, and it displays an exception, then you find the resource returned by findviewbyid is null,
most likely you are using the old style "id" in you xml layout file, change it to "android.id" will fix your problem.
*)if there is a compile error related to R.id.**, please build your project manually to refresh the R file.
if you perform a clean and build, eclipse may indicate you to fix project build path error, yet you just need to remove the R file and recreate it by building the project once again.