Create generalization for layout manager examples.

Will be used in a followup CL to simplify making examples for a new
layout manager without having to duplicate a bunch of code.

Change-Id: I3a37dc1656f70015170434c9da80ccbc20c1db88
Reviewed-on: https://chromium-review.googlesource.com/c/1351968Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611825}

ui/views/examples/BUILD.gn

@@ -33,6 +33,8 @@ jumbo_component("views_examples_lib") {
     "examples_window.h",
     "label_example.cc",
     "label_example.h",
+    "layout_example_base.cc",
+    "layout_example_base.h",
     "link_example.cc",
     "link_example.h",
     "menu_example.cc",

ui/views/examples/box_layout_example.h

@@ -8,9 +8,7 @@
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/label_button.h"
-#include "ui/views/controls/combobox/combobox_listener.h"
-#include "ui/views/controls/textfield/textfield_controller.h"
-#include "ui/views/examples/example_base.h"
+#include "ui/views/examples/layout_example_base.h"
 #include "ui/views/layout/box_layout.h"
 
 namespace views {
@@ -21,26 +19,14 @@ class Textfield;
 
 namespace examples {
 
-namespace {
-
-class ChildPanel;
-}
-
-class VIEWS_EXAMPLES_EXPORT BoxLayoutExample : public ExampleBase,
-                                               public ButtonListener,
-                                               public ComboboxListener,
-                                               public TextfieldController {
+class VIEWS_EXAMPLES_EXPORT BoxLayoutExample : public LayoutExampleBase {
  public:
   BoxLayoutExample();
   ~BoxLayoutExample() override;
 
-  // ExampleBase
-  void CreateExampleView(View* container) override;
-
  private:
-  friend views::examples::ChildPanel;
-  // ButtonListener
-  void ButtonPressed(Button* sender, const ui::Event& event) override;
+  // Set the border insets on the current BoxLayout instance.
+  void UpdateBorderInsets();
 
   // ComboboxListener
   void OnPerformAction(Combobox* combobox) override;
@@ -49,45 +35,12 @@ class VIEWS_EXAMPLES_EXPORT BoxLayoutExample : public ExampleBase,
   void ContentsChanged(Textfield* sender,
                        const base::string16& new_contents) override;
 
-  // Force the box_layout_panel_ to layout and repaint.
-  void RefreshLayoutPanel();
-
-  // Set the border insets on the current BoxLayout instance.
-  void UpdateBorderInsets();
-
-  // Create a new BoxLayout and ensure all settings match the current state of
-  // the various control_panel_ controls.
-  void UpdateLayoutManager();
-
-  // Create a Combobox with a label with |label_text| to the left. Adjust
-  // |vertical_pos| to |vertical_pos| + combo_box->height() + kSpacing.
-  Combobox* CreateCombobox(const base::string16& label_text,
-                           const char** items,
-                           int count,
-                           int& vertical_pos);
-
-  // Create just a Textfield at the current position of |horizontal_pos| and
-  // |vertical_pos|. Update |horizontal_pos| to |horizontal_pos| +
-  // text_field->width() + kSpacing.
-  Textfield* CreateRawTextfield(int& horizontal_pos,
-                                int vertical_pos,
-                                bool add);
-
-  // Create a Textfield with a label with |label_text| to the left. Adjust
-  // |vertical_pos| to |vertical_pos| + combo_box->height() + kSpacing.
-  Textfield* CreateTextfield(const base::string16& label_text,
-                             int& vertical_pos);
-
-  // Returns the current values contained in the child_panel_size_[] Textfields
-  // as a gfx::Size. If either value is negative or not a valid integer,
-  // default values are returned, 180 x 90 for width and height, respectively.
-  gfx::Size GetChildPanelSize() const;
+  // LayoutExampleBase
+  void ButtonPressedImpl(Button* sender) override;
+  void CreateAdditionalControls(int vertical_start_pos) override;
+  void UpdateLayoutManager() override;
 
   BoxLayout* layout_ = nullptr;
-  View* full_panel_ = nullptr;
-  View* box_layout_panel_ = nullptr;
-  View* control_panel_ = nullptr;
-  LabelButton* add_button_ = nullptr;
   Combobox* orientation_ = nullptr;
   Combobox* main_axis_alignment_ = nullptr;
   Combobox* cross_axis_alignment_ = nullptr;
@@ -95,9 +48,7 @@ class VIEWS_EXAMPLES_EXPORT BoxLayoutExample : public ExampleBase,
   Textfield* default_flex_ = nullptr;
   Textfield* min_cross_axis_size_ = nullptr;
   Textfield* border_insets_[4] = {nullptr, nullptr, nullptr, nullptr};
-  Textfield* child_panel_size_[2] = {nullptr, nullptr};
   Checkbox* collapse_margins_ = nullptr;
-  int panel_count_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(BoxLayoutExample);
 };

ui/views/examples/layout_example_base.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_VIEWS_EXAMPLES_LAYOUT_EXAMPLE_BASE_H_
+#define UI_VIEWS_EXAMPLES_LAYOUT_EXAMPLE_BASE_H_
+
+#include "ui/gfx/geometry/insets.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/views/controls/button/button.h"
+#include "ui/views/controls/button/checkbox.h"
+#include "ui/views/controls/button/label_button.h"
+#include "ui/views/controls/combobox/combobox_listener.h"
+#include "ui/views/controls/textfield/textfield_controller.h"
+#include "ui/views/examples/example_base.h"
+#include "ui/views/view.h"
+
+namespace views {
+namespace examples {
+
+// Provides an example of a layout manager with arbitrary specific manager and
+// controls. Lays out a sequence of ChildPanels in a view using the layout
+// manager of choice.
+class VIEWS_EXAMPLES_EXPORT LayoutExampleBase : public ExampleBase,
+                                                public ButtonListener,
+                                                public ComboboxListener,
+                                                public TextfieldController {
+ public:
+  // This view is created and added to the left-side view in the FullPanel each
+  // time the "Add" button is pressed. It also will display Textfield controls
+  // when the mouse is pressed over the view. These Textfields allow the user to
+  // interactively set each margin and the "flex" for the given view.
+  class ChildPanel : public View, public TextfieldController {
+   public:
+    ChildPanel(LayoutExampleBase* example, const gfx::Size& preferred_size);
+    ~ChildPanel() override;
+
+    // View
+    gfx::Size CalculatePreferredSize() const override;
+    bool OnMousePressed(const ui::MouseEvent& event) override;
+    void Layout() override;
+
+    void SetSelected(bool value);
+    bool selected() const { return selected_; }
+
+    int GetFlex();
+
+   private:
+    // TextfieldController
+    void ContentsChanged(Textfield* sender,
+                         const base::string16& new_contents) override;
+
+    Textfield* CreateTextfield();
+
+    LayoutExampleBase* example_;
+    bool selected_ = false;
+    Textfield* flex_;
+    Textfield* margin_[4];
+    gfx::Size preferred_size_;
+
+    DISALLOW_COPY_AND_ASSIGN(ChildPanel);
+  };
+
+  explicit LayoutExampleBase(const char* title);
+  ~LayoutExampleBase() override;
+
+  // Force the box_layout_panel_ to layout and repaint.
+  void RefreshLayoutPanel(bool update_layout);
+
+  static gfx::Size TextfieldsToSize(
+      Textfield* textfields[2],
+      const gfx::Size& default_size = gfx::Size());
+  static gfx::Insets TextfieldsToInsets(
+      Textfield* textfields[4],
+      const gfx::Insets& default_insets = gfx::Insets());
+
+ protected:
+  View* layout_panel() { return layout_panel_; }
+
+  // Creates a Combobox with a label with |label_text| to the left. Adjust
+  // |vertical_pos| to |vertical_pos| + combo_box->height() + kSpacing.
+  Combobox* CreateCombobox(const base::string16& label_text,
+                           const char* const* items,
+                           int count,
+                           int* vertical_pos);
+
+  // Creates just a Textfield at the current position of |horizontal_pos| and
+  // |vertical_pos|. Update |horizontal_pos| to |horizontal_pos| +
+  // text_field->width() + kSpacing.
+  Textfield* CreateRawTextfield(int vertical_pos,
+                                bool add,
+                                int* horizontal_pos);
+
+  // Creates a Textfield with a label with |label_text| to the left. Adjust
+  // |vertical_pos| to |vertical_pos| + combo_box->height() + kSpacing.
+  Textfield* CreateTextfield(const base::string16& label_text,
+                             int* vertical_pos);
+
+  // Creates a set of labeled Textfields with |label_text|, and four text fields
+  // arranged at compass points representing a set of insets. |vertical_pos| is
+  // updated to the bottom of the last Textfield + kSpacing, and |textfields| is
+  // populated with the fieds that are created.
+  void CreateMarginsTextFields(const base::string16& label_text,
+                               Textfield* textfields[4],
+                               int* vertical_pos);
+
+  // Creates a Checkbox with label |label_text|. Adjust |vertical_pos| to
+  // |vertical_pos| + checkbox->height() + kSpacing.
+  Checkbox* CreateCheckbox(const base::string16& label_text, int* vertical_pos);
+
+  // ButtonListener:
+  // Be sure to call LayoutExampleBase::ButtonPressed() to ensure the "add"
+  // button works correctly.
+  void ButtonPressed(Button* sender, const ui::Event& event) final;
+
+  // ExampleBase:
+  // Be sure to call LayoutExampleBase::CreateExampleView() to ensure default
+  // controls are created correctly.
+  void CreateExampleView(View* container) final;
+
+  // Called by CreateExampleView() to create any additional controls required by
+  // the specific layout. |vertical_start_pos| tells the control where to start
+  // placing new controls (i.e. the bottom of the existing common controls).
+  virtual void CreateAdditionalControls(int vertical_start_pos) = 0;
+
+  // Handles buttons added by derived classes after button handling for
+  // common controls is done.
+  virtual void ButtonPressedImpl(Button* sender);
+
+  // Performs layout-specific update of the layout manager.
+  virtual void UpdateLayoutManager() = 0;
+
+ private:
+  View* full_panel_ = nullptr;
+  View* layout_panel_ = nullptr;
+  View* control_panel_ = nullptr;
+  LabelButton* add_button_ = nullptr;
+  Textfield* child_panel_size_[2] = {nullptr, nullptr};
+  int panel_count_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(LayoutExampleBase);
+};
+
+}  // namespace examples
+}  // namespace views
+
+#endif  // UI_VIEWS_EXAMPLES_LAYOUT_EXAMPLE_BASE_H_