android - 登出。按下后退按钮，再次登录

Question

我正在从这个页面注销。它正在正确注销但是当按下后退按钮时它会再次登录。我已经给出了适当的 Intent 函数，但它并没有按照我的命令行事。请给我一个解决这个问题的建议。

WELCOME PAGE CODE:-

public class Welcome extends AppCompatActivity {

    Button __btnlogout;
    Button btn1;
    Button btn2;
    DatagramSocketThread mDatagramSocketThread;

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

        __btnlogout = (Button)findViewById(R.id.btnLogout);


        __btnlogout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                SharedPreferences pref= PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
                SharedPreferences.Editor editor = pref.edit();
                editor.putBoolean("isLogin", false);
                editor.commit();
                Intent intent = new Intent(Welcome.this,
                        login.class);
                intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(intent);

            }
        });




        btn1 = (Button)findViewById(R.id.btn11);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.e("MainActivity", "22");

                mDatagramSocketThread = new DatagramSocketThread();
                mDatagramSocketThread.start();
                Intent intent = VpnService.prepare(getApplicationContext());
                if (intent != null) {
                    startActivityForResult(intent, 0);
                } else {
                    onActivityResult(0, RESULT_OK, null);
                }
            }
        });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            Log.e("MainActivity", "23");

            Intent intent = new Intent(Welcome.this, MyClass.class);
            Log.e("MainActivity", "24");

            startService(intent);
        }

        btn2 = (Button)findViewById(R.id.btn22);
        btn2.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                Log.e("MainActivity", "25");

                Intent intent;
                intent = new Intent(Welcome.this, MyClass.class);
                Log.e("MainActivity", "26");

                stopService(intent);
            }
        });
    }
}

我想在注销时甚至在按下后退按钮后进入登录页面。

LOGIN PAGE CODE:-

public class login extends AppCompatActivity {
    SQLiteDatabase db;
    SQLiteOpenHelper openHelper;
    Button __btnLogin;
    EditText __txtEmail,__txtPass;
    Cursor cursor;




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





        Log.d("login","13");

        openHelper = new DatabaseHelper(this);
        db=openHelper.getReadableDatabase();
        __btnLogin = (Button)findViewById(R.id.btnLogins);


        __txtEmail = (EditText)findViewById(R.id.txtEmails);
        __txtPass = (EditText)findViewById(R.id.txtPasss);


        SharedPreferences pref= PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = pref.edit();
        editor.putBoolean("isLogin", true);
        editor.commit();






        Log.d("login","14");

        __btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String email = __txtEmail.getText().toString();
                String pass = __txtPass.getText().toString();




                if (pass == "" || email == "") {

                    Toast.makeText(getApplicationContext(),"No Entry", Toast.LENGTH_LONG).show();

                }



                Log.d("login","15");

                cursor = db.rawQuery("SELECT * FROM "+ DatabaseHelper.TABLE_NAME + " WHERE " + DatabaseHelper.COL_5 + " =? AND " + DatabaseHelper.COL_4 + " =? ", new String[]{email,pass});
                Log.d("login","16");

                if(cursor!=null) {
                    Log.d("login","17");

                    if (cursor.getCount()>0) {
                        Log.d("login","18");
                        //cursor.moveToNext();
                        Log.d("login","19");
                        startActivity(new Intent(login.this, Welcome.class));
                        Toast.makeText(getApplicationContext(), "Login Successfully", Toast.LENGTH_LONG).show();
                    }

                    else {
                        Log.d("login","20");
                        Toast.makeText(getApplicationContext(),"Error", Toast.LENGTH_LONG).show();
                        Log.d("login","21");
                    }
                }



            }
        });




    }
}

谢谢

Answer 1

您可以在登录页面覆盖 onBackPressed，然后当用户点击返回时，您可以按您的方式处理:

@Override
public void onBackPressed()
{
     //super.onBackPressed();  // disable this
}