android登录简单窗口

通过数据库用户表，进行一个简单的用户登录窗口，并且登录成功！




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>