Bulletproof Android™: Practical Advice for Building Secure Apps

Take 1

In the first example, we have a basic login screen asking for username, password, and email address (see Listing 3-3). We’re going to show how to check that they’re not empty and then throw up an alert dialog. If you don’t enter any data, then the alert dialog pops up (see line 44).

Listing 3-3 Validate text fields

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package com.riis.login;import android.os.Bundle;import android.app.Activity;import android.view.View;import android.widget.Button;import android.widget.EditText;public class LoginActivity extends Activity {    private Button loginButton;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.login_screen);