檢查共享首選項設置屏幕上的editText

Question

我想知道是否有辦法檢查某人在共享首選項/設置屏幕上輸入的內容以進行驗證。用戶觸摸IP輸入選項，彈出一個edittext對話框，我試圖限制他們可以輸入的東西像一個標準的IP地址（即0-255.0-255.0-255.0-255）我已經看過很多在線論壇並看到與REGEX和模式不同的事情的例子，這是我迄今爲止，但絕對沒有發生....任何人都可以幫我嗎？我將不勝感激！

public class PrefsActivity extends PreferenceActivity implements 
     OnSharedPreferenceChangeListener 
{ 
    private EditTextPreference ipTextBox; 
    private String whatWasTyped; 
    private String previousText = ""; 
    private Editor myEditor; 

    final Pattern IP_ADDRESS = Pattern 
      .compile("^((1\\d{2}|2[0-4]\\d|25[0-5]|\\d?\\d)\\.){3}(?:1\\d{2}|2[0-4]\\d|25[0-5]|\\d?\\d)$"); 
    private String IP_FROM_PREFS = "ipAddressPref"; 
    SharedPreferences prefs; 

    @Override 
    /** 
    * The onCreate method handles thing when starting this activity, 
    * mainly display the activity_settings.xml. 
    */ 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 

     // pattern for IP address validation 
     addPreferencesFromResource(R.layout.activity_settings); 

     // prefs.registerOnSharedPreferenceChangeListener(this); 

     prefs = PreferenceManager.getDefaultSharedPreferences(this); 
     // Get a reference to the preferences 
     ipTextBox = (EditTextPreference) getPreferenceScreen().findPreference(
       IP_FROM_PREFS); 

    } 

    @Override 
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, 
      String key) 
    { 
     // check prefs value for IP. 

     if (key.equals(IP_FROM_PREFS)) 
     { 

      whatWasTyped = prefs.getString(IP_FROM_PREFS, ""); 
      CharSequence s = whatWasTyped; 
      if (IP_ADDRESS.matcher(s).matches()) 
      { 
       previousText = s.toString(); 
          myEditor = prefs.edit(); 
          myEditor.putString(IP_FROM_PREFS, previousText); 
       myEditor.commit(); 

      } else 
      { 
       //if the format does not match, put up an error message 
          // or something. 

      } 
     } 

    } 

    @Override 
    protected void onResume() 
    { 
     super.onResume(); 

     // Setup the initial values 
     // mCheckBoxPreference.setSummary(sharedPreferences.getBoolean(key, 
     // false) ? "Disable this setting" : "Enable this setting"); 
     // mListPreference.setSummary("Current value is " + 
     // sharedPreferences.getValue(key, "")); 

     // Set up a listener whenever a key changes 
     getPreferenceScreen().getSharedPreferences() 
       .registerOnSharedPreferenceChangeListener(this); 
     previousText = prefs.getString(IP_FROM_PREFS, ""); 
    } 

    @Override 
    protected void onPause() 
    { 
     super.onPause(); 

     // Unregister the listener whenever a key changes 
     getPreferenceScreen().getSharedPreferences() 
       .unregisterOnSharedPreferenceChangeListener(this); 
    } 

} 

，因爲這是共享首選項屏幕上創建的東西，有沒有按鈕的ID，等...

Answer 1

只是寫

whatWasTyped.replace(s, previousText); 

不會分配的previousText到SharedPreference您需要將其分配回共享首選項並提交。