02-18 07:41:43.549: ERROR/AndroidRuntime(513): java.lang.NullPointerException
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at com.nj.dao.UsersSerive.getUsersByLoginI(UsersSerive.java:25)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at com.nj.dao.UsersDaoImpl.getUsersByLoginId(UsersDaoImpl.java:19)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at com.nj.dao.One$1.onClick(One.java:34)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.view.View.performClick(View.java:2408)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.view.View$PerformClick.run(View.java:8816)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.os.Handler.handleCallback(Handler.java:587)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.os.Handler.dispatchMessage(Handler.java:92)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.os.Looper.loop(Looper.java:123)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at java.lang.reflect.Method.invokeNative(Native Method)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at java.lang.reflect.Method.invoke(Method.java:521)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-18 07:41:43.549: ERROR/AndroidRuntime(513): at dalvik.system.NativeStart.main(Native Method)
这个是在运行到SQLiteDatabase sqlite=dbhelper.getWritableDatabase();这一步所出的错 求指导啊
下面的是我DBHelper的代码
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper{
private static final String name="mydata";
private static final int version=1;
public DBHelper(Context context) {
super(context, name, null, version);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table if not exists users(id integer primary key autoincrement,loginId varchar(50),password varchar(50))");
db.execSQL("insert into users(loginId,password) values('123','123')");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("drop table if exists users");
onCreate(db);
}
}
------解决方案--------------------