JavaFX：雙向綁定不會更新TextField

我在玩JavaFX並嘗試創建一個GUI，該GUI在更改後立即保存其狀態。JavaFX：雙向綁定不會更新TextField

類UiState封裝所有屬性：

public class UiState { 

    private static final Preferences PREFS = Preferences.userNodeForPackage(UiState.class); 
    public static final StringProperty FOLDER_PROP_STATISTICS = new BindingProperty("FOLDER_PROP_STATISTICS", 
     "C:\\Temp\\"); 

    //This is a Stringproperty, which accesses the Preferences 
    protected static class BindingProperty extends SimpleStringProperty { 
     private final String def; 
     private final String bindingName; 

     public BindingProperty(final String bindingName) { 
      this(bindingName, ""); 
     } 

     public BindingProperty(final String bindingName, final String def) { 
      this.def = def; 
      this.bindingName = bindingName; 
     } 

     @Override 
     public String get() { 
      return PREFS.get(bindingName, def); 
     } 

     @Override 
     public void set(final String newValue) { 
      PREFS.put(bindingName, newValue); 

     } 

    }

GUI是這樣創建的：

protected void configFileComponents() { 

    final TextField folderTextField = getPropertyTextFieldWithLabel("Target folder", UiState.FOLDER_PROP_STATISTICS); 

    folderTextField.setOnMouseClicked(target -> { 
     onFileChooseButtonClicked(); 

    }); 
} 

private void onFileChooseButtonClicked() { 
    final DirectoryChooser chooser = new DirectoryChooser(); 
    chooser.setTitle("Select target folder"); 
    final String folder = getFolderProperty().get(); 
    if (!(folder == null || folder.isEmpty())) { 
     chooser.setInitialDirectory(new File(folder)); 
    } 

    final File result = chooser.showDialog(getScene().getWindow()); 
    if (result != null) { 
     getFolderProperty().set(result.getAbsolutePath()); 
    } 
} 

protected TextField getPropertyTextFieldWithLabel(final String label, final StringProperty property) { 
    final Label fileLabel = new Label(label); 
    addLeft(fileLabel); 
    final TextField result = new TextField(); 
    result.setText(property.get()); 
    addRight(result); 
    //I thought this would be enough 
    result.textProperty().bindBidirectional(property); 
    return result; 
}

一旦一個文件夾經由DirectoryChooser選中，StringProperty FOLDER_PROP_STATISTICS被更新。但TextField不顯示新值。我錯過了什麼，或者我犯了一個根本的錯誤？

來源

2016-03-18 samjaf

你的'set'方法不觸發任何ChangeListeners或InvalidationListeners。正如你的問題所示，擴展StringProperty通常不是一個好主意。更好的辦法是使用Preferences節點中的鍵和值來初始化一個常規的StringProperty（或ObservableMap），並向它添加一個監聽器，以便可以在該首選項節點中對鏡像進行鏡像。 – VGR

非常感謝。一切正常，現在:) – samjaf

VGR是正確的，它覆蓋了get（）和set（）BindingProperty。我的新課程看起來像這樣，並且像一個魅力：

protected static class BindingProperty extends SimpleStringProperty { 

    public BindingProperty(final String bindingName, final String def) { 
     super(PREFS.get(bindingName, def)); 
     this.addListener(
       (ChangeListener<String>) (observable, oldValue, newValue) -> PREFS.put(bindingName, newValue)); 
    } 

    public BindingProperty(final String bindingName) { 
     this(bindingName, ""); 
    } 

}

來源

2016-03-18 17:49:24 samjaf

JavaFX：雙向綁定不會更新TextField

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