通過AlertDialog關閉活動並在稍後重新打開時崩潰

一切正常，直到我退出使用AlertDialog按鈕的活動並通過主菜單重新進入相同的對話框。通過AlertDialog關閉活動並在稍後重新打開時崩潰

下面是如何編碼的AlertDialog：如果我刪除上面的代碼

 AlertDialog.Builder builder = new AlertDialog.Builder(NewCustomerInfoActivity.this); 
     if (result.equals("{\"success\":true}")){ 
      builder.setMessage("Yeni müşteri başarıyla kaydedildi.").setTitle("Kayıt Başarılı"); 
      builder.setPositiveButton("Ana ekrana dön", new DialogInterface.OnClickListener() { 
       public void onClick(DialogInterface dialog, int id) { 
        Intent backToMainActivityIntent = new Intent(NewCustomerInfoActivity.this, MainActivity.class); 
        dialog.dismiss(); 
        startActivity(backToMainActivityIntent); 
       } 
      }); 
     } else { 
      builder.setMessage("Yeni müşteri kaydedilemedi.").setTitle("Kayıt Başarısız"); 
      builder.setPositiveButton("Tamam", new DialogInterface.OnClickListener() { 
       public void onClick(DialogInterface dialog, int id) { 
        dialog.dismiss(); 
       } 
      }); 
     } 
     AlertDialog dialog = builder.create(); 
     dialog.show();

，一切工作正常。

整個活動，如果有幫助：

public class NewCustomerInfoActivity extends AppCompatActivity { 
String jCities; 
ArrayList<City> cities; 
ArrayList<String> cityStrings; 
ArrayList<String> townStrings; 
RadioButton personalRadioButton; 
RadioButton corporateRadioButton; 
Spinner citySpinner; 
Spinner townSpinner; 
String url; 
int isPersComp = 1; 
String cityString = "Adana"; 
int cityNo = 1; 
String townString = "Aladağ"; 
int townNo = 1; 
JSONObject json; 
String deviceId; 
User user; 
String result; 
Toast toast; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_new_customer_info); 
    deviceId = Settings.Secure.getString(this.getContentResolver(), Settings.Secure.ANDROID_ID); 
    user = (User) getIntent().getSerializableExtra("user"); 
    url = getResources().getString(R.string.service_call_url) + "newCustomer/" + deviceId + "/" + user.getSecureSessionId() + "/"; 

    // Kayıtlı şehir ve ilçeler okunur. 
    SharedPreferences prefs = getSharedPreferences("cities", MODE_PRIVATE); 
    jCities = prefs.getString("jCities", null); 
    if (!(jCities.isEmpty() || jCities == null)){ 
     WebRequest webRequest = new WebRequest(); 
     cities = webRequest.parseCities(jCities); 
     cityStrings = new ArrayList<String>(); 
     for (City city : cities){ 
      if (!cityStrings.contains(city.getCityName())){ 
       cityStrings.add(city.getCityName()); 
      } 
     } 
    } 

    // Tüzel - Şahıs radio butonlarının kendilerine dokunulması durumunda tepkileri belirlenir. 
    personalRadioButton = (RadioButton) findViewById(R.id.personalRadioButton); 
    corporateRadioButton = (RadioButton) findViewById(R.id.corporateRadioButton); 
    isPersComp = 1; 
    View.OnClickListener optionOnClickListener = new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      TextView taxOrIdNoTitleTextView = (TextView) findViewById(R.id.taxOrIdNoTitleTextView); 

      if (personalRadioButton.isChecked()){ 
       taxOrIdNoTitleTextView.setText("TC Kimlik No:"); 
       isPersComp = 1; 
      } 
      if (corporateRadioButton.isChecked()){ 
       taxOrIdNoTitleTextView.setText("Vergi No:"); 
       isPersComp = 0; 
      } 
     } 
    }; 
    personalRadioButton.setOnClickListener(optionOnClickListener); 
    corporateRadioButton.setOnClickListener(optionOnClickListener); 

    // İl seçimi için spinner doldurulur. 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, cityStrings); 
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
    final Spinner citySpinner = (Spinner) findViewById(R.id.citySpinner); 
    citySpinner.setAdapter(adapter); 
    citySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
     @Override 
     public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { 
      cityString = citySpinner.getSelectedItem().toString(); 
      cityNo = 1 + citySpinner.getSelectedItemPosition(); 
      resetTownSpinner(cityNo); 
     } 
     @Override 
     public void onNothingSelected(AdapterView<?> adapterView) { 
     } 
    }); 
} 

// Şehir seçimi yapılınca çağırılan ve ilçe spinner'ını seçilen şehre göre dolduran fonksiyon. 
public void resetTownSpinner(int cityCode){ 
    townStrings = new ArrayList<String>(); 
    for (City city : cities){ 
     if (city.getCityCode() == cityCode){ 
      townStrings.add(city.getTownName()); 
     } 
    } 
    townSpinner = (Spinner) findViewById(R.id.townSpinner); 
    ArrayAdapter<String> townAdapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_spinner_item, townStrings); 
    townSpinner.setAdapter(townAdapter); 
    townSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
     @Override 
     public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { 
      townString = townSpinner.getSelectedItem().toString(); 
      townNo = 1 + townSpinner.getSelectedItemPosition(); 
     } 
     @Override 
     public void onNothingSelected(AdapterView<?> adapterView) { 
     } 
    }); 
} 

// Kayıt butonuna basıldığında çağırılan fonksiyon. 
public void saveNewCustomer (View view){ 

    // JSON objesi oluşturulur. 
    json = new JSONObject(); 
    try { 
     // JSON objesi kullanıcının girdiği değerlere göre doldurulur. 
     JSONObject jCustomer = new JSONObject(); 
     jCustomer.put("LOGICALREF", 0); 
     jCustomer.put("CODE", ""); 
     EditText definitionText = (EditText) findViewById(R.id.definitionText); 
     jCustomer.put("DEFINITION_", definitionText.getText().toString()); 
     jCustomer.put("ISPERSCOMP", isPersComp); 
     EditText taxOrIdNoText = (EditText) findViewById(R.id.taxOrIdNoText); 
     if (isPersComp == 1){ 
      jCustomer.put("TAXNR", ""); 
      jCustomer.put("TCKNO", taxOrIdNoText.getText().toString()); 
     } else { 
      jCustomer.put("TAXNR", taxOrIdNoText.getText().toString()); 
      jCustomer.put("TCKNO", ""); 
     } 
     EditText taxOfficeText = (EditText) findViewById(R.id.taxOfficeText); 
     String taxOfficeString = taxOfficeText.getText().toString(); 
     if (taxOfficeString.isEmpty() || taxOfficeString == null){ 
      jCustomer.put("TAXOFFICE", "TCKIMLIK"); 
     } else { 
      jCustomer.put("TAXOFFICE", taxOfficeString); 
     } 
     EditText emailText = (EditText) findViewById(R.id.emailText); 
     jCustomer.put("EMAILADDR", emailText.getText().toString()); 
     EditText address1Text = (EditText) findViewById(R.id.address1Text); 
     jCustomer.put("ADDR1", address1Text.getText().toString()); 
     EditText address2Text = (EditText) findViewById(R.id.address2Text); 
     jCustomer.put("ADDR2", address2Text.getText().toString()); 
     jCustomer.put("CITY", cityString); 
     jCustomer.put("CITYCODE", cityNo); 
     jCustomer.put("TOWN", townString); 
     jCustomer.put("TOWNCODE", townNo); 
     EditText inChargeText = (EditText) findViewById(R.id.inChargeText); 
     jCustomer.put("INCHARGE", inChargeText.getText().toString()); 
     EditText nameText = (EditText) findViewById(R.id.nameText); 
     jCustomer.put("NAME", nameText.getText().toString()); 
     EditText surnameText = (EditText) findViewById(R.id.surnameText); 
     jCustomer.put("SURNAME", surnameText.getText().toString()); 
     EditText phoneNo1Text = (EditText) findViewById(R.id.phoneNo1Text); 
     jCustomer.put("TELNRS1", phoneNo1Text.getText().toString()); 
     EditText phoneNo2Text = (EditText) findViewById(R.id.phoneNo2Text); 
     jCustomer.put("TELNRS2", phoneNo2Text.getText().toString()); 
     json.put("data", jCustomer); 

     // JSON objesini server'a gönderen Thread başlatılır. 
     new postJSON().execute(); 
    } catch (Exception e){ 
     e.printStackTrace(); 
    } 
} 

// JSON objesini server'a gönderen Thread. 
private class postJSON extends AsyncTask<Void, Void, Void>{ 
    ProgressDialog progressDialog; 

    protected void onPreExecute() { 
     super.onPreExecute(); 
     progressDialog = new ProgressDialog(NewCustomerInfoActivity.this); 
     progressDialog.setMessage("Yeni müşteri kaydediliyor. Lütfen bekleyiniz."); 
     progressDialog.setCancelable(false); 
     progressDialog.show(); 
    } 

    @Override 
    protected Void doInBackground(Void... arg0) { 
     WebRequest webRequest = new WebRequest(); 
     // JSON objesi string'e dönüştürülür ve linkin sonuna eklenir. 
     url = url + json.toString(); 
     result = webRequest.getJson(url, true); 
     return null; 
    } 

    protected void onPostExecute(Void requestResult) { 
     super.onPostExecute(requestResult); 
     if (progressDialog.isShowing()) { 
      progressDialog.dismiss(); 
     } 
     AlertDialog.Builder builder = new AlertDialog.Builder(NewCustomerInfoActivity.this); 
     // Server'dan dönen değer kontrol edilir. 
     if (result.equals("{\"success\":true}")){ 
      builder.setMessage("Yeni müşteri başarıyla kaydedildi.").setTitle("Kayıt Başarılı"); 
      builder.setPositiveButton("Ana ekrana dön", new DialogInterface.OnClickListener() { 
       public void onClick(DialogInterface dialog, int id) { 
        Intent backToMainActivityIntent = new Intent(NewCustomerInfoActivity.this, MainActivity.class); 
        dialog.dismiss(); 
        startActivity(backToMainActivityIntent); 
       } 
      }); 
     } else { 
      builder.setMessage("Yeni müşteri kaydedilemedi.").setTitle("Kayıt Başarısız"); 
      builder.setPositiveButton("Tamam", new DialogInterface.OnClickListener() { 
       public void onClick(DialogInterface dialog, int id) { 
        dialog.dismiss(); 
       } 
      }); 
     } 
     AlertDialog dialog = builder.create(); 
     dialog.show(); 
    } 
} 
}

同樣，沒有問題，只要AlertDialog不被使用。沒有問題，除非你使用AlertDialog，然後嘗試再次進入Activity，那麼應用程序停止工作。

logcat的：

07-27 13:14:16.113 28618-28618/eof.concrete E/AndroidRuntime: FATAL EXCEPTION: main 
                   Process: eof.concrete, PID: 28618 
                   java.lang.RuntimeException: Unable to start activity ComponentInfo{eof.concrete/eof.concrete.newCustomer.NewCustomerInfoActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String eof.concrete.classes.User.getSecureSessionId()' on a null object reference 
                    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817) 
                    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892) 
                    at android.app.ActivityThread.-wrap11(Unknown Source:0) 
                    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593) 
                    at android.os.Handler.dispatchMessage(Handler.java:105) 
                    at android.os.Looper.loop(Looper.java:164) 
                    at android.app.ActivityThread.main(ActivityThread.java:6540) 
                    at java.lang.reflect.Method.invoke(Native Method) 
                    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) 
                   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String eof.concrete.classes.User.getSecureSessionId()' on a null object reference 
                    at eof.concrete.newCustomer.NewCustomerInfoActivity.onCreate(NewCustomerInfoActivity.java:64) 
                    at android.app.Activity.performCreate(Activity.java:6980) 
                    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213) 
                    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770) 
                    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)  
                    at android.app.ActivityThread.-wrap11(Unknown Source:0)  
                    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)  
                    at android.os.Handler.dispatchMessage(Handler.java:105)  
                    at android.os.Looper.loop(Looper.java:164)  
                    at android.app.ActivityThread.main(ActivityThread.java:6540)  
                    at java.lang.reflect.Method.invoke(Native Method)  
                    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)  
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

來源

2017-07-27 GorkemSahin

將這段代碼

Intent backToMainActivityIntent = new Intent(NewCustomerInfoActivity.this, MainActivity.class); dialog.dismiss(); startActivity(backToMainActivityIntent);

把你的錯誤日誌請 –

如何先生，我可以那樣做嗎？ – GorkemSahin

打開你的日誌貓，複製錯誤行，將其粘貼 –

的問題是在這條線，而不是在AlertDialog

user = (User) getIntent().getSerializableExtra("user");

之前要調用getIntent()你需要確保你的活動已由創建意圖。當您的活動被Android框架銷燬並重新創建時，意圖將爲空。

如果意圖中的用戶對象是「活動」功能的基礎，那麼您可以完成它。

Intent intent = getIntent(); 
if (intent != null){ 
    user = (User) intent.getSerializableExtra("user"); 
    if (user == null){ 
     //handle null user 
    } 
} else { 
    //here you can call finish() if the user is fundamental to your Activity 
    //or you must handle a possible nullable `User` object in the following code 
    finish(); 
    return; 
}

而在你的AlertDialog，如果你想簡單地回到以前的活動，你可以用這個

dialog.dismiss(); 
finish();

來源

2017-07-27 13:33:01 MatPag

一旦我用finish（）替換了intent，它就工作了。謝謝。 – GorkemSahin

通過AlertDialog關閉活動並在稍後重新打開時崩潰

回答

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