Question

I have implemented activity with edittext and button:

After user entered a password and clicked a button, I’d like to verify the password and if it is correct open another activity. If the password is wrong I’d like to display an error message using AlertDialog.

Is it possible? How?

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.enter);


    //---load the SharedPreferences object---
    prefs = getSharedPreferences(prefName, MODE_PRIVATE);
    String a = prefs.getString(PASSWORD, "pa");
    System.out.println("saved Password" +a);    

    EditText et = (EditText)findViewById(R.id.txtName); 
    String theText = et.getText().toString();
    System.out.println("entered Password"+theText); 

    //---get the SharedPreferences object---
    prefs = getSharedPreferences(prefName, MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    editor.putString(PASSWORD, theText );

    //---save the values---
    editor.commit(); 


    Button data = (Button)findViewById(R.id.Ok);            
    data.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            Intent i = new Intent(Enter.this,Data.class);                
            startActivity(i);                   
        }   
    });

Answer 1

You can catch the password string into button click event.There,you can open a dialog depending on the correction of password.

Like:

EditText txtName=(EditText)findViewById(R.id.txtName);
Button login=(Button)findViewById(R.id.login);

login.setOnClickListener(new OnClickListener{

       public void onClick()
       {
           String password=txtName.getText().toString().trim();
          //verify the password and save result to boolean matching;
          if(matching)
               //open other activity
          else
          {
            AlertDialog.Builder alt_bld = new AlertDialog.Builder(this);
            alt_bld.setMessage("Password is invalid!")
                   .setCancelable(false)
                   .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                      public void onClick(DialogInterface dialog, int id) {
                         dialog.cancel();
                      }
               })
         });
         AlertDialog alert = alt_bld.create();
         // Title for AlertDialog
         alert.setTitle("Title");
         // Icon for AlertDialog
         alert.setIcon(R.drawable.icon);
         alert.show();
      }
    }
});