Android：意圖重新啓動活動，而不是指向主要的

Question

在我的應用程序中，我們有一個EnterPin活動，可以將引腳保存在SharedPreference中並將其與您輸入的內容進行比較。如果它是正確的，一個意圖帶你到MainActivity並傳​​遞一個真正的布爾值，並帶有「已驗證」的密鑰

由於某種原因，在仿真器和我的s7上，輸入正確的引腳（調試確認）後，只需重新啓動EnterPinActivity。

最令人討厭的部分是，它有時有效，有時不起作用。我不明白什麼可能導致這個問題。

EnterPin.java

public class EnterPin extends AppCompatActivity { 
//Used to check if there is a pin 
SharedPreferences preferences; 

//Title of the private file for the pin 
public final String PINFILE = "PinFile"; 

private int pin; 

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

    pin = getPinFromFile(); 

    //TODO::add similar check for security questions in case they exit the app during creation 
    //If the user did not create a pin, send to create one and end this activity 
    if(pin == -1) { 
     forceCreatePin(); 
     finish(); 
    } 

    Button logBtn = (Button)findViewById(R.id.logBtn); 
    Button forgotBtn = (Button)findViewById(R.id.forgotPin); 
} 

public void onClick(View v){ 
    if(v.getId() == R.id.logBtn){ 
     EditText pinIn = (EditText) findViewById(R.id.enterPin); 
     String pinStr = pinIn.getText().toString(); 
     if (pinStr.length() == 4) { 
      int pinInt = Integer.parseInt(pinStr); 
      if (pin == pinInt) { 
       //Login 
       Intent intent = new Intent(getApplicationContext(), MainActivity.class); 
       intent.putExtra("verified", true); 
       startActivity(intent); 
       finish(); 
      } else { 
       //clear input and notify user of wrong pin 
       pinIn.setText(""); 
       Toast toast = Toast.makeText(getApplicationContext(), "Incorrect PIN", Toast.LENGTH_SHORT); 
       toast.show(); 
      } 
     } else { 
      pinIn.setText(""); 
      Toast toast = Toast.makeText(getApplicationContext(), "PIN must be 4 characters", Toast.LENGTH_SHORT); 
      toast.show(); 
     } 
    }else if(v.getId() == R.id.forgotPin){ 
     Intent intent = new Intent(getApplicationContext(), ForgotPIN.class); 
     startActivity(intent); 
     finish(); 
    } 

} 

private int getPinFromFile() { 
    preferences = getSharedPreferences(PINFILE, MODE_PRIVATE); 
    //Returns value at key "pin" if it exists, -1 if pin is not created 
    return preferences.getInt(PINFILE, -1); 
} 

private void forceCreatePin() { 
    Intent intent = new Intent(this, CreatePin.class); 
    startActivity(intent); 
} 
} 

MainActivity.java

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 

    //get verified key from intent activity was started with, set false if key not found 
    isVerified = getIntent().getBooleanExtra("verified", false); 
    if (!isVerified) { 
     forceEnterPin(); 
    } 

//We create the db in the main class 
try { 
    db = this.openOrCreateDatabase("budgetDB", MODE_PRIVATE, null); 
    System.out.println("Succes!!!!!!!"); 

} 
catch(Exception e) 
{ 
    System.out.println("It got caught...."); 
    Log.e("BudgetDatabase ERROR", "Error Creating/Loading database"); 
} 
    Database budDB = new Database(db); 
    budDB.createTables(); 


    //Loading variables, settings the first fragment to the home screen 
    spendableInc = loadSpendableInc(); 
    FragmentTransaction trans = getFragmentManager().beginTransaction(); 
    HomeFragment homeFragment = new HomeFragment(); 
    trans.add(R.id.frag_container, homeFragment, "home").commit(); 


    //Settings functionality for the bottom navigation bar 
    final FrameLayout frameLayout = (FrameLayout) findViewById(R.id.frag_container); 
    BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation); 
    bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() { 
    @Override 
    public boolean onNavigationItemSelected(@NonNull MenuItem item) { 
     FragmentManager manager = getFragmentManager(); 
     final FragmentTransaction transaction = manager.beginTransaction(); 
     //Handling clicks on home, transaction, or overview 
     switch (item.getItemId()) { 
      case R.id.action_home: 
       HomeFragment homeFragment = new HomeFragment(); 
       transaction.replace(R.id.frag_container, homeFragment, "home").commit(); 
       break; 
      case R.id.action_transactions: 
       TransactionFragment transactionFragment = new TransactionFragment(); 
       transaction.replace(R.id.frag_container, transactionFragment, "transaction").commit(); 
       break; 
      case R.id.action_overview: 
       OverviewFragment overviewFragment = new OverviewFragment(); 
       transaction.replace(R.id.frag_container, overviewFragment, "overview").commit(); 
       break; 
     } 
     return false; 
    } 
}); 

} 

/** 
* Auto-generated method for toolbar 
* @param menu 
* @return 
*/ 
@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.menu_main, menu); 
    return true; 
} 

/** 
* Auto-generated method for toolbar 
* @param item 
* @return 
*/ 
@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(); 

    //noinspection SimplifiableIfStatement 
    if (id == R.id.action_settings) { 
     return true; 
    } else if (id == R.id.logout) { 
     forceEnterPin(); 
     return true; 
    } 

    return super.onOptionsItemSelected(item); 
} 


public void saveSpendableInc(float amt) { 
    SharedPreferences.Editor editor = getSharedPreferences(SPENDABLE_INCOME, MODE_PRIVATE).edit(); 
    editor.putFloat(SPENDABLE_INCOME, amt); 
    editor.commit(); 
} 

public float loadSpendableInc() { 
    SharedPreferences prefs = getSharedPreferences(SPENDABLE_INCOME, MODE_PRIVATE); 
    return prefs.getFloat(SPENDABLE_INCOME, MODE_PRIVATE); 
} 

public void createIncome(View view) { 
    Intent intent = new Intent(this, CreateIncome.class); 
    intent.putExtra(SPENDABLE_INCOME, spendableInc); 
    startActivity(intent); 
} 

public void createExpense(View view) { 
    Intent intent = new Intent(this, CreateExpense.class); 
    intent.putExtra(SPENDABLE_INCOME, spendableInc); 
    startActivity(intent); 
} 

/** 
* Closes the database when the application is terminated 
* Set verified to false to force 
*/ 
@Override 
protected void onDestroy(){ 
    super.onDestroy(); 
    db.close(); 
    getIntent().putExtra("verified", false); 
    idleStart = 0; 
    idleFinish = 0; 
} 

//Forces user to create pin and ends the main activity so the user can't use the back button to get to home screen 
private void forceEnterPin() { 
    getIntent().putExtra("verified", false); 
    Intent intent = new Intent(this, EnterPin.class); 
    startActivity(intent); 
    //finish(); 
} 

@Override 
protected void onPause(){ 
    super.onPause(); 
    Calendar tmpCalendar = Calendar.getInstance(); 
    idleStart = tmpCalendar.get(Calendar.MINUTE); 
} 

@Override 
protected void onStop(){ 
    super.onStop(); 
    Calendar tmpCalendar = Calendar.getInstance(); 

    //If app went straight to stop phase, start at 0 
    //If app started at pause and then went to stop, add time from before 
    if(idleStart == 0) 
     idleStart = tmpCalendar.get(Calendar.MINUTE); 
    else 
     idleStart += tmpCalendar.get(Calendar.MINUTE); 
} 

@Override 
protected void onResume(){ 
    super.onResume(); 
    //Use calendar object to get the current time in minutes 
    Calendar tmpCalendar = Calendar.getInstance(); 
    idleFinish = tmpCalendar.get(Calendar.MINUTE); 
    if(idleFinish - idleStart >= 30) 
     forceEnterPin(); 

    //Reset idle times because user started app again 
    idleStart = 0; 
    idleFinish = 0; 
} 
} 

Answer 1

答：讀你第一次使用這個API，你讓它開始活動了你面前。