Android記住以前的登錄（backgroundtask）

Question

我試圖有一個登錄，檢查用戶是否存在於mysql數據庫，但運行應用程序時，它會記住以前的登錄信息。我認爲問題出在後臺任務上，好像我評論一下，我可以爲登錄細節敬酒。

public class Tab1Activity extends Activity 
{ 
    String task,username,password; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.tab1); 

     final Button buta = (Button) findViewById(R.id.button1); 
     final Button butb = (Button) findViewById(R.id.button2); 
     final TextView usernameTV = (TextView) findViewById(R.id.editText1); 
     final TextView passwordTV = (TextView) findViewById(R.id.editText2); 

     buta.setOnClickListener(new View.OnClickListener() 
     { 
      public void onClick(View v) 
      { 
       SharedPreferences preferences = getSharedPreferences("MYPREFS", Context.MODE_PRIVATE); 
       //editor = preferences.edit(); 

       username=usernameTV.getText().toString(); 
       password=passwordTV.getText().toString(); 
       task="login"; 
       Toast.makeText(getApplicationContext(), username+" "+password, Toast.LENGTH_SHORT).show(); 

       // create and call background activity         

       BackgroundTask backgroundTaskLogin = new BackgroundTask(Tab1Activity.this);     
       backgroundTaskLogin.execute(task,username,password); 

       //get data back from sharedpreference 
       String driver_exist = preferences.getString("myDatalogin","ERROR getting name"); 

       //display datas 
       String[] loginSeparated = driver_exist.split(","); 
       Toast.makeText(getApplicationContext(), loginSeparated[0], Toast.LENGTH_SHORT).show(); 


       if (loginSeparated[0].equals("true")) 
       { 

       int finalId = Integer.parseInt(loginSeparated[1]); 
       //Toast.makeText(getApplicationContext(), loginSeparated[1], Toast.LENGTH_SHORT).show(); 

       SharedPreferences.Editor editor = getSharedPreferences("MYPREFS", Context.MODE_PRIVATE).edit(); 
       editor.putInt("TaxiDriverId", finalId); 
       editor.apply(); 

       //once clicked - jump to tab2 
       TabActivity tabs = (TabActivity) getParent(); 
       tabs.getTabHost().setCurrentTab(1); 
       } 
       else 
       { 
        Toast.makeText(getApplicationContext(), "Wrong password", Toast.LENGTH_SHORT).show(); 
       } 
      } 
     }); 
    } 

    ////////////////////////////////////////////////////// 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.tab1, menu); 
     return true; 
     } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 
     if (id == R.id.action_settings) { 
      return true; 
     } 
     return super.onOptionsItemSelected(item); 
    } 
} 

這是我認爲問題出在哪裏的背景討論。

public class BackgroundTask extends AsyncTask<String,Void,String> 
    { 

     SharedPreferences preferences; 
     SharedPreferences.Editor editor; 
     SharedPreferences.Editor pig; 

     Context context; 

     BackgroundTask(Context ctx) 
     { 
      this.context = ctx; 
     } 

     @Override 
     protected String doInBackground(String... params) 
     { 
      String urlLogin = ""; 
      preferences = context.getSharedPreferences("MYPREFS", Context.MODE_PRIVATE); 
      editor = preferences.edit(); 
      editor.putString("flag","0"); 
      editor.commit(); 

      String task = params[0]; 
      String loginusername; 
      String loginpassword; 


      if (task.equals("login")) 
      {   
       urlLogin = "http://super.com/LoginAndRegister-login.php"; 
       loginusername = params[1]; 
       loginpassword = params[2]; 



       try 
       { 
        URL url = new URL(urlLogin); 
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); 
        httpURLConnection.setRequestMethod("POST"); 
        httpURLConnection.setDoOutput(true); 
        httpURLConnection.setDoInput(true); 


        //send the driver number to the database 
        OutputStream outputStream = httpURLConnection.getOutputStream(); 
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream,"UTF-8"); 
        BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter); 

        String myDatalogin = URLEncoder.encode("identifier_loginEmail","UTF-8")+"="+URLEncoder.encode(loginusername,"UTF-8") 
        +"&"+URLEncoder.encode("identifier_loginPassword","UTF-8")+"="+URLEncoder.encode(loginpassword,"UTF-8"); 
        bufferedWriter.write(myDatalogin); 
        bufferedWriter.flush(); 
        bufferedWriter.close(); 
        outputStream.close(); 

        //get response from the database 
        InputStream inputStream = httpURLConnection.getInputStream(); 
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"UTF-8"); 
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader); 
        String dataResponse = ""; 
        String inputLine = ""; 
        while((inputLine = bufferedReader.readLine()) != null) 
        { 
         dataResponse += inputLine; 
        } 
        bufferedReader.close(); 
        inputStream.close(); 
        httpURLConnection.disconnect(); 

        editor.putString("flag","login"); 
        editor.commit();          
        pig = preferences.edit(); 
        pig.putString("myDatalogin",dataResponse); 
        pig.commit();    
        return dataResponse; 
       } 
       catch (MalformedURLException e) 
       { 
        e.printStackTrace(); 
       } 
       catch (IOException e) 
       { 
        e.printStackTrace(); 
       } 

      }//end if statement 

Answer 1

當你與Activity呼叫finish()這樣做將確保活動下次啓動時它會重新開始。還請查看AndroidManifest.xml中的Activity標記中的launchMode屬性，以確保您正確開始了您的活動。 https://developer.android.com/guide/topics/manifest/activity-element.html