android登录简单窗口

下面是原代码：
package com.smart.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SQLite extends SQLiteOpenHelper{
    public static final String TB_NAME = "smrtDataBase";
    //构造方法
    public SQLite(Context context) {

      super(context, TB_NAME, null, 1);
    }

    /**
      * 创建数据库表
      */
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE users (userId integer primary key autoincrement,name varchar(20),password varchar(20))");
    }

    /**
      * 当检测与前一次创建数据库版本不一样时，先删除表再创建新表
      */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      db.execSQL("DROP TABLE IF EXISTS users");
      onCreate(db);
    }







}
package com.smart.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class UserImpl {
    private SQLite sqlite;
    private Context content;
    private SQLiteDatabase db;

    public UserImpl(Context context) {

        sqlite = new SQLite(context);
    }
//登录方法
    public Cursor login(String name, String pwd) {
        SQLiteDatabase database = sqlite.getReadableDatabase();
        Cursor mCursor = database.query(true, "users", new String[] { "name" },
                "name=? and password=?", new String[] { name, pwd }, null,
                null, null, null);
        return mCursor;
    }
//保存方法
    public boolean save(String name, String password) {
        SQLiteDatabase database = sqlite.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put("name", name);
        values.put("password", password);
        // 必须添加记录,除了主键之处，其它都要null
        database.insert("users", "name", values);
        return true;
    }

}
package com.smart.loginActivity;

import com.smart.db.UserImpl;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class LoginMain extends Activity {

    private static final String TAG = "LoginMain";
    private Button ok;
    private Button exit;
    private EditText name;
    private EditText password;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);//得到控件
        ok = (Button) findViewById(R.id.ok);
        exit = (Button) findViewById(R.id.exit);
        name = (EditText) findViewById(R.id.username);
        password = (EditText) findViewById(R.id.password);
        ok.setOnClickListener(new OnClickListener() {//方法编写
            @Override
            public void onClick(View v) {
                Log.i(TAG, name.getText().toString() + "<----passord---->"
                        + password.getText().toString());
                try {
                    UserImpl impl = new UserImpl(LoginMain.this);
                    Cursor cursor = impl.login(name.getText().toString(), password.getText().toString());// 得到记录
                    if (cursor.moveToNext()) {//进行判断数据库当中是否有记得
                        Toast.makeText(LoginMain.this, "成功登录！", Toast.LENGTH_LONG)
                                .show();

                    } else {
                        Toast.makeText(LoginMain.this, "你的用户名或密码错误，请重新输入",
                                Toast.LENGTH_LONG).show();
                        name.setText("");
                        password.setText("");
                    }
                } catch (Exception e) {
                    Log.i(TAG, "报错了");
                }

            }
        });
        //取消
        exit.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {

                Log.i(TAG, name.getText().toString() + "<----passord---->"
                        + password.getText().toString());
                Toast.makeText(LoginMain.this, "你点击了取消!", Toast.LENGTH_LONG)
                        .show();
                finish();
            }
        });
    }
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content">

<TextView
    android:layout_width="100dip"
    android:layout_height="wrap_content"
    android:text="@string/userName"
    />
<EditText
    android:layout_width="200dip"
    android:layout_height="wrap_content"
    android:textSize="15dip"
    android:id="@+id/username"
    />
    </LinearLayout>
    <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content">

<TextView
    android:layout_width="100dip"
    android:layout_height="wrap_content"
    android:text="@string/userPwd"
    />
<EditText
    android:layout_width="200dip"
    android:layout_height="wrap_content"
    android:textSize="15dip"
    android:id="@+id/password"
    android:password="true"
    />

    </LinearLayout>

    <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content">
<Button

    android:layout_width="100dip"
    android:layout_height="wrap_content"
    android:text="@string/ok"
    android:id="@+id/ok"
    />

    <Button

    android:layout_width="100dip"
    android:layout_height="wrap_content"
    android:text="@string/exit"
    android:id="@+id/exit"
    />
    </LinearLayout>
</LinearLayout>