即使应用程序关闭，如何暂时禁用按钮？

Question

So I created a simple login activity. The login button will be disabled for a period of time when the user failed to login 3 times.

My struggle is when I close the app and open it again the button is enabled back. How to fix this?

Here's my code:

public class LoginControl extends Activity {
private DBControl db = new DBControl(this);
int counter = 2;
Button login = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.loginview);


    Button register = (Button) findViewById(R.id.btnCreateA);
    login = (Button) findViewById(R.id.btnLogin);
    login.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            try {
                EditText a = (EditText) findViewById(R.id.etUser);
                EditText b = (EditText) findViewById(R.id.etPassword);
                String user = a.getText().toString();
                String pass = b.getText().toString();
                String confirm = db.getUserPass(user);
                if (user.equals("") || pass.equals("")) {
                    Toast passed = Toast.makeText(LoginControl.this, "Please input required fields.", Toast.LENGTH_LONG);
                    passed.show();
                } else if (pass.equals(confirm)) {
                    Toast passed = Toast.makeText(LoginControl.this, "Sucess!", Toast.LENGTH_LONG);
                    passed.show();
                    Intent intent = new Intent(LoginControl.this, HomeControl.class).putExtra("Music", false);
                    startActivity(intent);
                    finish();

                } else if (counter == 0)
                // Disable button after 3 failed attempts
                {

                    login.setEnabled(false);

                    Toast alert = Toast.makeText(LoginControl.this, "Login Disabled for 5 mins", Toast.LENGTH_LONG);
                    alert.show();

                    final Handler handler = new Handler();
                    handler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            login.setEnabled(true);
                            counter = 2;
                        }
                    }, 30000);
                } else {
                    Toast passed = Toast.makeText(LoginControl.this, "Username or password don't match!", Toast.LENGTH_LONG);
                    counter--;
                    passed.show();
                }
            } catch (Exception e) {
                Toast passed = Toast.makeText(LoginControl.this, e.toString(), Toast.LENGTH_LONG);
                passed.show();
            }
        }
    });
}

}

Answer 1

To get this information, even if the app is restarted, you need to save the time when the button will be enabled again. When your app starts you can open this information and check if it is before or after this time.

There are several methods, how you can store information on android:

• Shared Preferences: https://developer.android.com/training/basics/data-storage/shared-preferences.html
• SQLite Database: https://developer.android.com/training/basics/data-storage/databases.html
• Save as File: https://developer.android.com/training/basics/data-storage/files.html

For your problem I would suggest that you should use Shared Preferences.

Answer 2

Using shared preferences, save the state of your button after login.setEnabled(false) :

SharedPreferences prefs = this.getSharedPreferences("MyApp", Context.MODE_PRIVATE);
boolean enabled = login.isEnabled();
prefs.edit().putBoolean("LOGIN_ENABLED_KEY", enabled).apply();

Just after getting hold of the login button in onCreate , check for the presence of this value (using true as the default value):

SharedPreferences prefs = this.getSharedPreferences("MyApp", Context.MODE_PRIVATE);
boolean enabled = prefs.getBoolean("LOGIN_ENABLED_KEY", true);
login.setEnabled(enabled);

If the button is disabled at this point, you need to restart the timer so that it eventually gets enabled:

if (!enabled) {
    final Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            login.setEnabled(true);
            prefs.edit().clear().apply();
            counter = 2;
        }
    }, 30000);
}

When the timer elapses:

SharedPreferences prefs = this.getSharedPreferences("MyApp", Context.MODE_PRIVATE);
prefs.edit().putBoolean("LOGIN_ENABLED_KEY", true).apply();

Alternatively, just clear the shared preferences:

SharedPreferences prefs = this.getSharedPreferences("MyApp", Context.MODE_PRIVATE);
prefs.edit().clear().apply();

---

Putting it all together, something roughly like this:

int counter = 2;
Button login = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.loginview);

    final SharedPreferences prefs = this.getSharedPreferences("MyApp", Context.MODE_PRIVATE);
    login = (Button) findViewById(R.id.btnLogin);
    boolean enabled = prefs.getBoolean("LOGIN_ENABLED_KEY", true);
    login.setEnabled(enabled);
    if (!enabled) {
        final Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                login.setEnabled(true);
                prefs.edit().clear().apply();
                counter = 2;
            }
        }, 30000);
    }

    login.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
             try {
                 EditText a = (EditText) findViewById(R.id.etUser);
                 EditText b = (EditText) findViewById(R.id.etPassword);
                 String user = a.getText().toString();
                 String pass = b.getText().toString();
                 if (user.equals("") || pass.equals("")) {
                     Toast passed = Toast.makeText(LoginControl.this, "Please input required fields.", Toast.LENGTH_LONG);
                     passed.show();
                 } else if (pass.equals("pass")) {
                     Toast passed = Toast.makeText(LoginControl.this, "Success!", Toast.LENGTH_LONG);
                     passed.show();
                     // Start HomeControl + finish()
                 } else if (counter == 0) {
                     // Disable button after 3 failed attempts
                     login.setEnabled(false);
                     prefs.edit().putBoolean("LOGIN_ENABLED_KEY", false).apply();
                     Toast alert = Toast.makeText(LoginControl.this, "Login Disabled for 5 mins", Toast.LENGTH_LONG);
                     alert.show();

                     final Handler handler = new Handler();
                     handler.postDelayed(new Runnable() {
                         @Override
                         public void run() {
                             login.setEnabled(true);
                             prefs.edit().clear().apply();
                             counter = 2;
                         }
                     }, 30000);
                 } else {
                     Toast passed = Toast.makeText(LoginControl.this, "Username or password don't match!", Toast.LENGTH_LONG);
                     counter--;
                     passed.show();
                 }
             } catch (Exception e) {
                 Toast passed = Toast.makeText(LoginControl.this, e.toString(), Toast.LENGTH_LONG);
                 passed.show();
             }
         }
    });
}

(There is clearly room for some refactoring here, but this does work.)