Settings Tutorial

As discussed in the Settings Guide, plugins can add Settings to IntelliJ Platform-based IDEs. The IDE displays the Settings in response to a user choosing Settings. Custom Settings are displayed and function just like those native to the IDE.

Overview of Custom Settings Implementation

Using the SDK code sample settings, this tutorial illustrates the steps to create custom Application-level Settings. Many IntelliJ Platform Settings implementations use fewer classes, but the settings code sample factors the functionality into three classes for clarity:

The AppSettingsConfigurable is analogous to a Controller in the MVC model - it interacts with the other two Settings classes and the IntelliJ Platform,
The AppSettingsState is like a Model because it stores the Settings persistently,
The AppSettingsComponent is similar to a View because it displays and captures edits to the values of the Settings.

The structure of the implementation is the same for Project Settings, but there are minor differences in the Configurable implementation and extension point (EP) declaration.

The `AppSettingsState` Class

The AppSettingsState class persistently stores the custom Settings. It is based on the IntelliJ Platform Persistence Model.

Declaring `AppSettingsState`

Given a Light Service is not used, the persistent data class must be declared as a Service EP in the plugin.xml file. If these were Project Settings, the com.intellij.projectService EP would be used. However, because these are Application Settings, the com.intellij.applicationService EP is used with the fully qualified name (FQN) of the implementation class:

<extensions defaultExtensionNs="com.intellij">
  <applicationService
      serviceImplementation="org.intellij.sdk.settings.AppSettingsState"/>
</extensions>

Creating the `AppSettingState` Implementation

As discussed in Implementing the PersistentStateComponent Interface, AppSettingsState uses the pattern of implementing PersistentStateComponent itself:

/**
 * Supports storing the application settings in a persistent way.
 * The {@link State} and {@link Storage} annotations define the name of the data and the file name where
 * these persistent application settings are stored.
 */
@State(
    name = "org.intellij.sdk.settings.AppSettingsState",
    storages = @Storage("SdkSettingsPlugin.xml")
)
final class AppSettingsState implements PersistentStateComponent<AppSettingsState> {

  public String userId = "John Q. Public";
  public boolean ideaStatus = false;

  static AppSettingsState getInstance() {
    return ApplicationManager.getApplication().getService(AppSettingsState.class);
  }

  @Override
  public AppSettingsState getState() {
    return this;
  }

  @Override
  public void loadState(@NotNull AppSettingsState state) {
    XmlSerializerUtil.copyBean(state, this);
  }

}

`@Storage` Annotation

The @State annotation, located just above the class declaration, defines the data storage location. For AppSettingsState, the data name parameter is the FQN of the class. Using FQN is the best practice to follow, and is required if custom data gets stored in the standard project or workspace files.

The storages parameter utilizes the @Storage annotation to define a custom file name for the AppSettingsState data. In this case, the file is located in the options directory of the configuration directory for the IDE.

Persistent Data Fields

The AppSettingState implementation has two public fields: a String and a boolean. Conceptually, these fields hold the name of a user, and whether that person is an IntelliJ IDEA user, respectively. See Implementing the State Class for more information about how PersistentStateComponent serializes public fields.

`AppSettingState` Methods

The fields are so limited and straightforward for this class that encapsulation is not used for simplicity. All that's needed for functionality is to override the two methods called by the IntelliJ Platform when a new component state is loaded (PersistentStateComponent.loadState()), and when a state is saved (PersistentStateComponent.getState()). See PersistentStateComponent for more information about these methods.

One static convenience method has been added - AppSettingState.getInstance() - which allows AppSettingsConfigurable to easily acquire a reference to AppSettingState.

The `AppSettingsComponent` Class

The role of the AppSettingsComponent is to provide a JPanel for the custom Settings to the IDE Settings Dialog. The AppSettingsComponent has-a JPanel, and is responsible for its lifetime. The AppSettingsComponent is instantiated by AppSettingsConfigurable.

Creating the `AppSettingsComponent` Implementation

The AppSettingsComponent defines a JPanel containing a JBTextField and a JBCheckBox to hold and display the data that maps to the data fields of AppSettingsState:

/**
 * Supports creating and managing a {@link JPanel} for the Settings Dialog.
 */
public class AppSettingsComponent {

  private final JPanel myMainPanel;
  private final JBTextField myUserNameText = new JBTextField();
  private final JBCheckBox myIdeaUserStatus = new JBCheckBox("Do you use IntelliJ IDEA? ");

  public AppSettingsComponent() {
    myMainPanel = FormBuilder.createFormBuilder()
        .addLabeledComponent(new JBLabel("Enter user name: "), myUserNameText, 1, false)
        .addComponent(myIdeaUserStatus, 1)
        .addComponentFillVertically(new JPanel(), 0)
        .getPanel();
  }

  public JPanel getPanel() {
    return myMainPanel;
  }

  public JComponent getPreferredFocusedComponent() {
    return myUserNameText;
  }

  @NotNull
  public String getUserNameText() {
    return myUserNameText.getText();
  }

  public void setUserNameText(@NotNull String newText) {
    myUserNameText.setText(newText);
  }

  public boolean getIdeaUserStatus() {
    return myIdeaUserStatus.isSelected();
  }

  public void setIdeaUserStatus(boolean newStatus) {
    myIdeaUserStatus.setSelected(newStatus);
  }

}

`AppSettingsComponent` Methods

The constructor builds the JPanel using the convenient FormBuilder, and saves a reference to the JPanel. The rest of the class are simple accessors and mutators to encapsulate the UI components used on the JPanel.

The `AppSettingsConfigurable` Class

The methods of AppSettingsConfigurable are called by the IntelliJ Platform, and AppSettingsConfigurable in turn interacts with AppSettingsComponent and AppSettingState.

Declaring the `AppSettingsConfigurable`

As described in Declaring Application Settings, the com.intellij.applicationConfigurable is used as the EP. An explanation of this declaration can be found in Declaring Application Settings:

<extensions defaultExtensionNs="com.intellij">
  <applicationConfigurable
      parentId="tools"
      instance="org.intellij.sdk.settings.AppSettingsConfigurable"
      id="org.intellij.sdk.settings.AppSettingsConfigurable"
      displayName="SDK: Application Settings Example"/>
</extensions>

Creating the `AppSettingsConfigurable` Implementation

The AppSettingsConfigurable class implements Configurable interface. The class has one field to hold a reference to the AppSettingsComponent.

/**
 * Provides controller functionality for application settings.
 */
final class AppSettingsConfigurable implements Configurable {

  private AppSettingsComponent mySettingsComponent;

  // A default constructor with no arguments is required because this implementation
  // is registered in an applicationConfigurable EP

  @Nls(capitalization = Nls.Capitalization.Title)
  @Override
  public String getDisplayName() {
    return "SDK: Application Settings Example";
  }

  @Override
  public JComponent getPreferredFocusedComponent() {
    return mySettingsComponent.getPreferredFocusedComponent();
  }

  @Nullable
  @Override
  public JComponent createComponent() {
    mySettingsComponent = new AppSettingsComponent();
    return mySettingsComponent.getPanel();
  }

  @Override
  public boolean isModified() {
    AppSettingsState settings = AppSettingsState.getInstance();
    boolean modified = !mySettingsComponent.getUserNameText().equals(settings.userId);
    modified |= mySettingsComponent.getIdeaUserStatus() != settings.ideaStatus;
    return modified;
  }

  @Override
  public void apply() {
    AppSettingsState settings = AppSettingsState.getInstance();
    settings.userId = mySettingsComponent.getUserNameText();
    settings.ideaStatus = mySettingsComponent.getIdeaUserStatus();
  }

  @Override
  public void reset() {
    AppSettingsState settings = AppSettingsState.getInstance();
    mySettingsComponent.setUserNameText(settings.userId);
    mySettingsComponent.setIdeaUserStatus(settings.ideaStatus);
  }

  @Override
  public void disposeUIResources() {
    mySettingsComponent = null;
  }

}

`AppSettingsConfigurable` Methods

All the methods in this class are overrides of the methods in the Configurable interface. Readers are encouraged to review the Javadoc comments for the Configurable methods. Also review notes about IntelliJ Platform Interactions with Configurable methods.

Testing the Custom Settings Plugin

After performing the steps described above, compile and run the plugin in a Development Instance to see the custom Settings available in the Settings Dialog. Open the IDE Settings by selecting Settings | Tools | SDK: Application Settings Example. The settings are preloaded with the default values:

Now edit the settings values to "John Doe" and click the checkbox. Click on the OK button to close the Settings dialog and save the changes. Exit the Development Instance.

Open the file SdkSettingsPlugin.xml to see the Settings persistently stored. In this demonstration the file resides in code_samples/settings/build/idea-sandbox/config/options/, but see IDE Development Instances for the general Development Instance case, or Default IDE directories if you are testing the settings plugin directly in an IDE.

Last modified: 08 April 2024

Settings Tutorial

Overview of Custom Settings Implementation

The AppSettingsState Class

Declaring AppSettingsState

Creating the AppSettingState Implementation

@Storage Annotation

Persistent Data Fields

AppSettingState Methods

The AppSettingsComponent Class

Creating the AppSettingsComponent Implementation

AppSettingsComponent Methods

The AppSettingsConfigurable Class

Declaring the AppSettingsConfigurable

Creating the AppSettingsConfigurable Implementation

AppSettingsConfigurable Methods