当我在sdcard中尝试createFile时:我得到的日志如下:
W/System.err: at java.io.UnixFileSystem.createFileExclusively0(Native方法)
W/System.err: at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java
: Unable to start activity ComponentInfo{com.groupchat/com.groupchat.LogIn}: java.lang.NullPointerException:102)09-2413:47:52.195: E/AndroidRuntime(1467): at android.app.A