小波Linux安卓Sqlite資料庫實現用戶登錄註冊，通俗易懂！

看了很多別人寫的安卓SQlite數據的操作代碼，都是浮雲，瞎弄！一點也不通俗易懂，我覺得我寫的不錯，而且安卓項目也用上了，所以在博客園裡保存分享一下！

一SQLiteHelper類是自動重載增刪改查函數的，另外一個是自己定義的類，用Context傳值。我用的是Fragment，用Activity的話吧getActivity()去掉！

實現了用戶登錄註冊的功能！

http://www.cnblogs.com/xiaobo-Linux/ （小波）趙存檔QQ463431476

public class MySqliteHelper extends SQLiteOpenHelper {

    //自定義訪問sqlite
    public MySqliteHelper(Context context) {
        super(context, "userdb.db", null, 3);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
     //http://www.cnblogs.com/xiaobo-Linux/ （小波）趙存檔QQ463431476
        db.execSQL("create table users(id int primary key ,name text,pwd text)");
          
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        
    }
 
}

public class Userlogin extends Activity implements  OnClickListener{
    
       
       private MySqliteHelper helper;
       
       Button sign;  
       Button reg;
       
       String  name;
       String  mypwd;
       private EditText user;
       private EditText pwd;
       
      
   //http://www.cnblogs.com/xiaobo-Linux/ （小波）趙存檔QQ463431476
 
   public void onCreate(Bundle savedInstanceState) {  
       super.onCreate(savedInstanceState);
       //設置狀態欄顏色 
       getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
       getWindow().setStatusBarColor(getResources().getColor(R.color.StatusBar));   
       //設置actionbar顏色 
       ActionBar actionBar = getActionBar();
       actionBar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#0099CC")));
       setContentView(R.layout.login);
       
       findViewById(R.id.button1).setOnClickListener(this);
       findViewById(R.id.button2).setOnClickListener(this);
       user = (EditText)findViewById(R.id.editText1);
       pwd=(EditText)findViewById(R.id.editText2);
     
   }  
 
   
 public void  insert()
 {
     

      helper = new MySqliteHelper(getApplicationContext());
      SQLiteDatabase db=helper.getWritableDatabase();    
      
      //查詢一下，是否用戶名重覆
       String sql1 = "select * from users";
       Cursor cursor = db.rawQuery(sql1, null);
       while (cursor.moveToNext()) {
          //第一列為id
          name =  cursor.getString(1); //獲取第2列的值,第一列的索引從0開始
          mypwd = cursor.getString(2);//獲取第3列的值
         
      }
      
     if((user.getText().toString().equals(name)))
         {
                Toast.makeText(this, "已存在此用戶，請重新註冊", Toast.LENGTH_SHORT).show(); 
         }
         else
          {
             String sql2 = "insert into users(name,pwd) values ('"+user.getText().toString()+"','"+pwd.getText().toString()+"')";
                db.execSQL(sql2);
               Toast.makeText(this, "註冊成功！", Toast.LENGTH_SHORT).show(); 
          }
     
 }
 
  public void select()
 {
     
      helper = new MySqliteHelper(getApplicationContext());
      SQLiteDatabase db=helper.getWritableDatabase();
        
      String sql = "select * from users";
      
      Cursor cursor = db.rawQuery(sql, null);
      while (cursor.moveToNext()) {
          //第一列為id
          name =  cursor.getString(1); //獲取第2列的值,第一列的索引從0開始
          mypwd = cursor.getString(2);//獲取第3列的值
         
      }
      
      if((user.getText().toString().equals(name))&&(pwd.getText().toString().equals(mypwd)))
         {
                Toast.makeText(this, "用戶驗證成功", Toast.LENGTH_SHORT).show(); 
                Intent MainActivity = new Intent();
                MainActivity .setClass(this,MainActivity.class);
                  this.startActivity(MainActivity);  
                  finish();//退出
         }
         else
          {
                Toast.makeText(this, "賬號或者密碼錯誤,請重新輸入", Toast.LENGTH_SHORT).show();  
          }
      
                cursor.close();
                db.close();
                //Toast.makeText(this, "已經關閉資料庫", Toast.LENGTH_SHORT).show();  
 }


@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
       switch(v.getId()){  
        case R.id.button1:  
            select();
         
            break;  
        case R.id.button2:  
            insert();
            break;  
         }
 
}
 
    

http://www.cnblogs.com/xiaobo-Linux/ （小波）趙存檔QQ463431476

效果如下：