求助，用户注册登录模块，输入字母按注册或登录就闪退？

Question

各位大神：          大家好，求助，如题。
          参考网上一个用户注册登录模块：
          1）用户名和密码只能是数字才能注册或登录；
          2）不注册时，用户名和密码随意输入数字，会弹出“用户名和密码不对”，但输入字母，就直接闪退了。
          不注册时，用户名输入"a"，密码输入“1”，闪退，调试码如下：
01-07 08:30:05.057 20031-20031/com.example.foolishfan.user_v10 I/UserDataManager: UserDataManager construction!
 01-07 08:30:11.924 20031-20031/com.example.foolishfan.user_v10 I/UserDataManager: findUserByNameAndPwd
 01-07 08:30:11.924 20031-20031/com.example.foolishfan.user_v10 E/SQLiteLog: (1) no such column: a
 01-07 08:30:11.925 20031-20031/com.example.foolishfan.user_v10 D/AndroidRuntime: Shutting down VM
 01-07 08:30:11.926 20031-20031/com.example.foolishfan.user_v10 E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                  Process: com.example.foolishfan.user_v10, PID: 20031
                                                                                  android.database.sqlite.SQLiteException: no such column: a (code 1): , while compiling: SELECT * FROM users WHERE user_name=a and user_pwd=1
                                                                                      at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                                                                                      at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:887)
                                                                                      at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:498)
                                                                                      at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                                                                                      at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
                                                                                      at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
                                                                                      at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
                                                                                      at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
                                                                                      at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
                                                                                      at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
                                                                                      at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
                                                                                      at com.example.foolishfan.user_v10.UserDataManager.findUserByNameAndPwd(UserDataManager.java:151)
                                                                                      at com.example.foolishfan.user_v10.Login.login(Login.java:122)
                                                                                      at com.example.foolishfan.user_v10.Login$1.onClick(Login.java:94)
                                                                                      at android.view.View.performClick(View.java:5207)
                                                                                      at android.view.View$PerformClick.run(View.java:21177)
                                                                                      at android.os.Handler.handleCallback(Handler.java:739)
                                                                                      at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                      at android.os.Looper.loop(Looper.java:148)
                                                                                      at android.app.ActivityThread.main(ActivityThread.java:5438)
                                                                                      at java.lang.reflect.Method.invoke(Native Method)
                                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
                                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)
 01-07 08:30:11.948 20031-20031/com.example.foolishfan.user_v10 I/Process: Sending signal. PID: 20031 SIG: 9
请大神帮忙下！谢谢了。

Answer 1

链接地址：https://pan.baidu.com/s/1kUX0qX5
参考文章：http://blog.csdn.net/it_beecoder/article/details/52801135

Answer 2

android.database.sqlite.SQLiteException: no such column: a (code 1): , while compiling: SELECT * FROM users WHERE user_name=a and user_pwd=1,这里很清楚，你的sqlite报错了

Answer 3

user_name应该是字符型的字段吧，值应该加引号