Persist tool window open states during project open/close

resources/META-INF/plugin.xml

@@ -1565,6 +1565,14 @@
               topic="com.intellij.openapi.project.ProjectManagerListener"/>
   </applicationListeners>
 
+  <projectListeners>
+    <listener class="io.flutter.view.FlutterViewFactory$FlutterViewListener" topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+    <listener class="io.flutter.performance.FlutterPerformanceViewFactory$FlutterPerformanceViewListener"
+              topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+    <listener class="io.flutter.preview.PreviewViewFactory$PreviewViewListener"
+              topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+  </projectListeners>
+
   <extensionPoints>
     <extensionPoint name="gradleSyncProvider" interface="io.flutter.android.GradleSyncProvider"/>
     <extensionPoint name="colorPickerProvider" interface="io.flutter.editor.ColorPickerProvider"/>

resources/META-INF/plugin_template.xml

@@ -246,6 +246,14 @@
               topic="com.intellij.openapi.project.ProjectManagerListener"/>
   </applicationListeners>
 
+  <projectListeners>
+    <listener class="io.flutter.view.FlutterViewFactory$FlutterViewListener" topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+    <listener class="io.flutter.performance.FlutterPerformanceViewFactory$FlutterPerformanceViewListener"
+              topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+    <listener class="io.flutter.preview.PreviewViewFactory$PreviewViewListener"
+              topic="com.intellij.openapi.wm.ex.ToolWindowManagerListener"/>
+  </projectListeners>
+
   <extensionPoints>
     <extensionPoint name="gradleSyncProvider" interface="io.flutter.android.GradleSyncProvider"/>
     <extensionPoint name="colorPickerProvider" interface="io.flutter.editor.ColorPickerProvider"/>

src/io/flutter/performance/FlutterPerformanceViewFactory.java

@@ -5,6 +5,7 @@
  */
 package io.flutter.performance;
 
+import com.intellij.ide.util.PropertiesComponent;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.project.DumbAware;
@@ -13,17 +14,24 @@
 import com.intellij.openapi.wm.ToolWindow;
 import com.intellij.openapi.wm.ToolWindowFactory;
 import com.intellij.openapi.wm.ToolWindowManager;
+import io.flutter.utils.ViewListener;
 import io.flutter.view.FlutterViewMessages;
 import org.jetbrains.annotations.NotNull;
 
 public class FlutterPerformanceViewFactory implements ToolWindowFactory, DumbAware {
+  private static final String TOOL_WINDOW_VISIBLE_PROPERTY = "flutter.performance.tool.window.visible";
+
   public static void init(@NotNull Project project) {
     project.getMessageBus().connect().subscribe(
       FlutterViewMessages.FLUTTER_DEBUG_TOPIC, (event) -> initPerfView(project, event)
     );
     final ToolWindow window = ToolWindowManager.getInstance(project).getToolWindow(FlutterPerformanceView.TOOL_WINDOW_ID);
     if (window != null) {
       window.setAvailable(true);
+
+      if (PropertiesComponent.getInstance(project).getBoolean(TOOL_WINDOW_VISIBLE_PROPERTY, false)) {
+        window.activate(null, false);
+      }
     }
   }
 
@@ -47,4 +55,10 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
   public boolean shouldBeAvailable(@NotNull Project project) {
     return false;
   }
+
+  public static class FlutterPerformanceViewListener extends ViewListener {
+    public FlutterPerformanceViewListener(@NotNull Project project) {
+      super(project, FlutterPerformanceView.TOOL_WINDOW_ID, TOOL_WINDOW_VISIBLE_PROPERTY);
+    }
+  }
 }

src/io/flutter/preview/PreviewViewFactory.java

@@ -5,20 +5,30 @@
  */
 package io.flutter.preview;
 
+import com.intellij.ide.util.PropertiesComponent;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.project.DumbAware;
 import com.intellij.openapi.project.DumbService;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.wm.ToolWindow;
 import com.intellij.openapi.wm.ToolWindowFactory;
 import com.intellij.openapi.wm.ToolWindowManager;
+import com.intellij.openapi.wm.ex.ToolWindowManagerListener;
+import io.flutter.performance.FlutterPerformanceView;
+import io.flutter.utils.ViewListener;
 import org.jetbrains.annotations.NotNull;
 
 public class PreviewViewFactory implements ToolWindowFactory, DumbAware {
+  private static final String TOOL_WINDOW_VISIBLE_PROPERTY = "flutter.preview.tool.window.visible";
+
   public static void init(@NotNull Project project) {
     final ToolWindow window = ToolWindowManager.getInstance(project).getToolWindow(PreviewView.TOOL_WINDOW_ID);
     if (window != null) {
       window.setAvailable(true);
+
+      if (PropertiesComponent.getInstance(project).getBoolean(TOOL_WINDOW_VISIBLE_PROPERTY, false)) {
+        window.activate(null, false);
+      }
     }
   }
 
@@ -34,4 +44,10 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
   public boolean shouldBeAvailable(@NotNull Project project) {
     return false;
   }
+
+  public static class PreviewViewListener extends ViewListener {
+    public PreviewViewListener(@NotNull Project project) {
+      super(project, PreviewView.TOOL_WINDOW_ID, TOOL_WINDOW_VISIBLE_PROPERTY);
+    }
+  }
 }

src/io/flutter/utils/ViewListener.java

@@ -0,0 +1,32 @@
+package io.flutter.utils;
+
+import com.intellij.ide.util.PropertiesComponent;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.wm.ToolWindow;
+import com.intellij.openapi.wm.ToolWindowManager;
+import com.intellij.openapi.wm.ex.ToolWindowManagerListener;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Helps to initialize a tool window with the same visibility state as when the project was previously closed.
+ */
+public abstract class ViewListener implements ToolWindowManagerListener {
+  private final @NotNull Project project;
+  private final String toolWindowId;
+  private final String toolWindowVisibleProperty;
+
+  public ViewListener(@NotNull Project project, String toolWindowId, String toolWindowVisibleProperty) {
+    this.project = project;
+    this.toolWindowId = toolWindowId;
+    this.toolWindowVisibleProperty = toolWindowVisibleProperty;
+  }
+
+  @Override
+  public void stateChanged(@NotNull ToolWindowManager toolWindowManager) {
+    ToolWindow toolWindow = toolWindowManager.getToolWindow(toolWindowId);
+    // We only make tool windows available once we've found a Flutter project, so we want to avoid setting the visible property until then.
+    if (toolWindow != null && toolWindow.isAvailable()) {
+      PropertiesComponent.getInstance(project).setValue(toolWindowVisibleProperty, toolWindow.isVisible(), false);
+    }
+  }
+}

src/io/flutter/view/FlutterViewFactory.java

@@ -5,6 +5,7 @@
  */
 package io.flutter.view;
 
+import com.intellij.ide.util.PropertiesComponent;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.project.DumbAware;
@@ -13,9 +14,12 @@
 import com.intellij.openapi.wm.ToolWindow;
 import com.intellij.openapi.wm.ToolWindowFactory;
 import com.intellij.openapi.wm.ToolWindowManager;
+import io.flutter.utils.ViewListener;
 import org.jetbrains.annotations.NotNull;
 
 public class FlutterViewFactory implements ToolWindowFactory, DumbAware {
+  private static final String TOOL_WINDOW_VISIBLE_PROPERTY = "flutter.view.tool.window.visible";
+
   public static void init(@NotNull Project project) {
     project.getMessageBus().connect().subscribe(
       FlutterViewMessages.FLUTTER_DEBUG_TOPIC, (event) -> initFlutterView(project, event)
@@ -24,6 +28,10 @@ public static void init(@NotNull Project project) {
     final ToolWindow window = ToolWindowManager.getInstance(project).getToolWindow(FlutterView.TOOL_WINDOW_ID);
     if (window != null) {
       window.setAvailable(true);
+
+      if (PropertiesComponent.getInstance(project).getBoolean(TOOL_WINDOW_VISIBLE_PROPERTY, false)) {
+        window.activate(null, false);
+      }
     }
   }
 
@@ -46,4 +54,10 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
       (ServiceManager.getService(project, FlutterView.class)).initToolWindow(toolWindow);
     });
   }
+
+  public static class FlutterViewListener extends ViewListener {
+    public FlutterViewListener(@NotNull Project project) {
+      super(project, FlutterView.TOOL_WINDOW_ID, TOOL_WINDOW_VISIBLE_PROPERTY);
+    }
+  }
 }