BoxLayout now suports per-view margins.

ui/views/examples/box_layout_example.cc

+// Copyright 2017 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.
+
+#include "box_layout_example.h"
+
+#include <vector>
+
+#include "base/memory/ptr_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/base/models/combobox_model.h"
+#include "ui/gfx/geometry/insets.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/button/checkbox.h"
+#include "ui/views/controls/button/md_text_button.h"
+#include "ui/views/controls/combobox/combobox.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/controls/textfield/textfield.h"
+#include "ui/views/examples/example_combobox_model.h"
+#include "ui/views/layout/fill_layout.h"
+#include "ui/views/view.h"
+
+namespace views {
+namespace examples {
+
+namespace {
+
+// This View holds two other views which consists of a view on the left onto
+// which the BoxLayout is attached for demonstrating its features. The view
+// on the right contains all the various controls which allow the user to
+// interactively control the various features/properties of BoxLayout. Layout()
+// will ensure the left view takes 75% and the right view fills the remaining
+// 25%.
+class FullPanel : public View {
+ public:
+  FullPanel() {}
+  ~FullPanel() override {}
+
+  // View
+  void Layout() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FullPanel);
+};
+
+// 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:
+  explicit ChildPanel(BoxLayoutExample* example);
+  ~ChildPanel() override {}
+
+  // View
+  gfx::Size GetPreferredSize() 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();
+
+  BoxLayoutExample* example_;
+  bool selected_ = false;
+  Textfield* flex_;
+  Textfield* margin_[4];
+
+  DISALLOW_COPY_AND_ASSIGN(ChildPanel);
+};
+
+void FullPanel::Layout() {
+  DCHECK_EQ(child_count(), 2);
+  View* left_panel = child_at(0);
+  View* right_panel = child_at(1);
+  gfx::Rect bounds = GetContentsBounds();
+  left_panel->SetBounds(bounds.x(), bounds.y(), (bounds.width() * 75) / 100,
+                        bounds.height());
+  right_panel->SetBounds(left_panel->width(), bounds.y(),
+                         bounds.width() - left_panel->width(), bounds.height());
+}
+
+ChildPanel::ChildPanel(BoxLayoutExample* example) : View(), example_(example) {
+  SetBorder(CreateSolidBorder(1, SK_ColorGRAY));
+  for (unsigned i = 0; i < sizeof(margin_) / sizeof(margin_[0]); ++i)
+    margin_[i] = CreateTextfield();
+  flex_ = CreateTextfield();
+  flex_->SetText(base::ASCIIToUTF16(""));
+}
+
+gfx::Size ChildPanel::GetPreferredSize() const {
+  return gfx::Size(180, 90);
+}
+
+bool ChildPanel::OnMousePressed(const ui::MouseEvent& event) {
+  if (event.IsOnlyLeftMouseButton())
+    SetSelected(true);
+  return true;
+}
+
+void ChildPanel::Layout() {
+  const int kSpacing = 2;
+  if (selected_) {
+    gfx::Rect client = GetContentsBounds();
+    for (unsigned i = 0; i < sizeof(margin_) / sizeof(margin_[0]); ++i) {
+      gfx::Point pos;
+      Textfield* textfield = margin_[i];
+      switch (i) {
+        case 0:
+          pos = gfx::Point((client.width() - textfield->width()) / 2, kSpacing);
+          break;
+        case 1:
+          pos =
+              gfx::Point(kSpacing, (client.height() - textfield->height()) / 2);
+          break;
+        case 2:
+          pos = gfx::Point((client.width() - textfield->width()) / 2,
+                           client.height() - textfield->height() - kSpacing);
+          break;
+        case 3:
+          pos = gfx::Point(client.width() - textfield->width() - kSpacing,
+                           (client.height() - textfield->height()) / 2);
+          break;
+        default:
+          NOTREACHED();
+      }
+      textfield->SetPosition(pos);
+    }
+    flex_->SetPosition(gfx::Point((client.width() - flex_->width()) / 2,
+                                  (client.height() - flex_->height()) / 2));
+  }
+}
+
+void ChildPanel::SetSelected(bool value) {
+  if (value != selected_) {
+    selected_ = value;
+    SetBorder(CreateSolidBorder(1, selected_ ? SK_ColorBLACK : SK_ColorGRAY));
+    if (selected_ && parent()) {
+      for (int i = 0; i < parent()->child_count(); ++i) {
+        View* child = parent()->child_at(i);
+        if (child != this && child->GetGroup() == GetGroup()) {
+          ChildPanel* child_panel = static_cast<ChildPanel*>(child);
+          child_panel->SetSelected(false);
+        }
+      }
+    }
+    for (Textfield* textfield : margin_)
+      textfield->SetVisible(selected_);
+    flex_->SetVisible(selected_);
+    InvalidateLayout();
+    example_->RefreshLayoutPanel();
+  }
+}
+
+int ChildPanel::GetFlex() {
+  int flex;
+  if (base::StringToInt(flex_->text(), &flex))
+    return flex;
+  return -1;
+}
+
+void ChildPanel::ContentsChanged(Textfield* sender,
+                                 const base::string16& new_contents) {
+  int edges[4];
+  for (unsigned i = 0; i < sizeof(margin_) / sizeof(margin_[0]); ++i) {
+    base::StringToInt(margin_[i]->text(), &edges[i]);
+  }
+  gfx::Insets margins = gfx::Insets(edges[0], edges[1], edges[2], edges[3]);
+  if (!margins.IsEmpty())
+    this->SetProperty(kMarginsKey, new gfx::Insets(margins));
+  else
+    this->ClearProperty(kMarginsKey);
+  if (sender == flex_)
+    example_->UpdateLayoutManager();
+  example_->RefreshLayoutPanel();
+}
+
+Textfield* ChildPanel::CreateTextfield() {
+  Textfield* textfield = new Textfield();
+  textfield->set_default_width_in_chars(3);
+  textfield->SizeToPreferredSize();
+  textfield->SetText(base::ASCIIToUTF16("0"));
+  textfield->set_controller(this);
+  textfield->SetVisible(false);
+  AddChildView(textfield);
+  return textfield;
+}
+
+const int kSpacing = 3;
+const int kPadding = 8;
+const int kMaxPanels = 5;
+const int kChildPanelGroup = 100;
+const char* orientation_values[2] = {"Horizontal", "Vertical"};
+const char* main_axis_values[3] = {"Start", "Center", "End"};
+const char* cross_axis_values[4] = {"Stretch", "Start", "Center", "End"};
+}
+
+BoxLayoutExample::BoxLayoutExample() : ExampleBase("Box Layout") {}
+
+BoxLayoutExample::~BoxLayoutExample() {}
+
+Combobox* BoxLayoutExample::CreateCombobox(const base::string16& label_text,
+                                           const char** items,
+                                           int count,
+                                           int& vertical_pos) {
+  Label* label = new Label(label_text);
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  Combobox* combo_box =
+      new Combobox(base::MakeUnique<ExampleComboboxModel>(items, count));
+  combo_box->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  combo_box->SizeToPreferredSize();
+  combo_box->set_listener(this);
+  label->SetSize(gfx::Size(label->width(), combo_box->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(combo_box);
+  vertical_pos += combo_box->height() + kSpacing;
+  return combo_box;
+}
+
+Textfield* BoxLayoutExample::CreateRawTextfield(int& horizontal_pos,
+                                                int vertical_pos,
+                                                bool add) {
+  Textfield* text_field = new Textfield();
+  text_field->SetPosition(gfx::Point(horizontal_pos, vertical_pos));
+  text_field->set_default_width_in_chars(3);
+  text_field->SetTextInputType(ui::TEXT_INPUT_TYPE_NUMBER);
+  text_field->SizeToPreferredSize();
+  text_field->SetText(base::ASCIIToUTF16("0"));
+  text_field->set_controller(this);
+  horizontal_pos += text_field->width() + kSpacing;
+  if (add)
+    control_panel_->AddChildView(text_field);
+  return text_field;
+}
+
+Textfield* BoxLayoutExample::CreateTextfield(const base::string16& label_text,
+                                             int& vertical_pos) {
+  Label* label = new Label(label_text);
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  int horizontal_pos = label->x() + label->width() + kSpacing;
+  Textfield* text_field =
+      CreateRawTextfield(horizontal_pos, vertical_pos, false);
+  label->SetSize(gfx::Size(label->width(), text_field->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(text_field);
+  vertical_pos += text_field->height() + kSpacing;
+  return text_field;
+}
+
+void BoxLayoutExample::CreateExampleView(View* container) {
+  container->SetLayoutManager(new FillLayout());
+  full_panel_ = new FullPanel();
+  container->AddChildView(full_panel_);
+
+  box_layout_panel_ = new View();
+  box_layout_panel_->SetBorder(CreateSolidBorder(1, SK_ColorLTGRAY));
+  full_panel_->AddChildView(box_layout_panel_);
+  control_panel_ = new View();
+  full_panel_->AddChildView(control_panel_);
+
+  int vertical_pos = kSpacing;
+  add_button_ =
+      MdTextButton::CreateSecondaryUiButton(this, base::ASCIIToUTF16("Add"));
+  add_button_->SetPosition(gfx::Point(kPadding, vertical_pos));
+  add_button_->SizeToPreferredSize();
+  control_panel_->AddChildView(add_button_);
+  vertical_pos += add_button_->height() + kSpacing;
+
+  orientation_ = CreateCombobox(base::ASCIIToUTF16("Orientation"),
+                                orientation_values, 2, vertical_pos);
+  main_axis_alignment_ = CreateCombobox(base::ASCIIToUTF16("Main axis"),
+                                        main_axis_values, 3, vertical_pos);
+  cross_axis_alignment_ = CreateCombobox(base::ASCIIToUTF16("Cross axis"),
+                                         cross_axis_values, 4, vertical_pos);
+
+  between_child_spacing_ =
+      CreateTextfield(base::ASCIIToUTF16("Child spacing"), vertical_pos);
+  default_flex_ =
+      CreateTextfield(base::ASCIIToUTF16("Default flex"), vertical_pos);
+  min_cross_axis_size_ =
+      CreateTextfield(base::ASCIIToUTF16("Min cross axis"), vertical_pos);
+
+  border_insets_[0] =
+      CreateTextfield(base::ASCIIToUTF16("Insets"), vertical_pos);
+  int horizontal_pos =
+      border_insets_[0]->x() + border_insets_[0]->width() + kSpacing;
+  for (unsigned i = 1; i < sizeof(border_insets_) / sizeof(border_insets_[0]);
+       ++i)
+    border_insets_[i] =
+        CreateRawTextfield(horizontal_pos, border_insets_[0]->y(), true);
+
+  collapse_margins_ = new Checkbox(base::ASCIIToUTF16("Collapse margins"));
+  collapse_margins_->SetPosition(gfx::Point(kPadding, vertical_pos));
+  collapse_margins_->SizeToPreferredSize();
+  collapse_margins_->set_listener(this);
+  control_panel_->AddChildView(collapse_margins_);
+
+  UpdateLayoutManager();
+}
+
+void BoxLayoutExample::ButtonPressed(Button* sender, const ui::Event& event) {
+  if (sender == add_button_) {
+    if (panel_count_ < kMaxPanels) {
+      ++panel_count_;
+      ChildPanel* panel = new ChildPanel(this);
+      panel->SetGroup(kChildPanelGroup);
+      box_layout_panel_->AddChildView(panel);
+      RefreshLayoutPanel();
+    } else {
+      PrintStatus("Only %i panels may be added", kMaxPanels);
+    }
+  } else if (sender == collapse_margins_) {
+    UpdateLayoutManager();
+    RefreshLayoutPanel();
+  }
+}
+
+void BoxLayoutExample::OnPerformAction(Combobox* combobox) {
+  if (combobox == orientation_) {
+    UpdateLayoutManager();
+  } else if (combobox == main_axis_alignment_) {
+    layout_->set_main_axis_alignment(static_cast<BoxLayout::MainAxisAlignment>(
+        main_axis_alignment_->selected_index()));
+  } else if (combobox == cross_axis_alignment_) {
+    layout_->set_cross_axis_alignment(
+        static_cast<BoxLayout::CrossAxisAlignment>(
+            cross_axis_alignment_->selected_index()));
+  }
+  RefreshLayoutPanel();
+}
+
+void BoxLayoutExample::ContentsChanged(Textfield* textfield,
+                                       const base::string16& new_contents) {
+  if (textfield == between_child_spacing_) {
+    UpdateLayoutManager();
+  } else if (textfield == default_flex_) {
+    int default_flex;
+    base::StringToInt(default_flex_->text(), &default_flex);
+    layout_->SetDefaultFlex(default_flex);
+  } else if (textfield == min_cross_axis_size_) {
+    int min_cross_size;
+    base::StringToInt(min_cross_axis_size_->text(), &min_cross_size);
+    layout_->set_minimum_cross_axis_size(min_cross_size);
+  } else if (textfield == border_insets_[0] || textfield == border_insets_[1] ||
+             textfield == border_insets_[2] || textfield == border_insets_[3]) {
+    UpdateBorderInsets();
+  }
+  RefreshLayoutPanel();
+}
+
+void BoxLayoutExample::RefreshLayoutPanel() {
+  box_layout_panel_->Layout();
+  box_layout_panel_->SchedulePaint();
+}
+
+void BoxLayoutExample::UpdateBorderInsets() {
+  int inset_values[4];
+  for (unsigned i = 0; i < sizeof(border_insets_) / sizeof(border_insets_[0]);
+       ++i)
+    base::StringToInt(border_insets_[i]->text(), &inset_values[i]);
+  layout_->set_inside_border_insets(gfx::Insets(
+      inset_values[0], inset_values[1], inset_values[2], inset_values[3]));
+}
+
+void BoxLayoutExample::UpdateLayoutManager() {
+  int child_spacing;
+  int default_flex;
+  int min_cross_size;
+  base::StringToInt(between_child_spacing_->text(), &child_spacing);
+  base::StringToInt(default_flex_->text(), &default_flex);
+  base::StringToInt(min_cross_axis_size_->text(), &min_cross_size);
+  layout_ = new BoxLayout(orientation_->selected_index() == 0
+                              ? BoxLayout::Orientation::kHorizontal
+                              : BoxLayout::Orientation::kVertical,
+                          0, 0, child_spacing, collapse_margins_->checked());
+  layout_->set_cross_axis_alignment(static_cast<BoxLayout::CrossAxisAlignment>(
+      cross_axis_alignment_->selected_index()));
+  layout_->set_main_axis_alignment(static_cast<BoxLayout::MainAxisAlignment>(
+      main_axis_alignment_->selected_index()));
+  layout_->SetDefaultFlex(default_flex);
+  layout_->set_minimum_cross_axis_size(min_cross_size);
+  UpdateBorderInsets();
+  for (int i = 0; i < box_layout_panel_->child_count(); ++i) {
+    ChildPanel* panel =
+        static_cast<ChildPanel*>(box_layout_panel_->child_at(i));
+    int flex = panel->GetFlex();
+    if (flex < 0)
+      layout_->ClearFlexForView(panel);
+    else
+      layout_->SetFlexForView(panel, flex);
+  }
+  box_layout_panel_->SetLayoutManager(layout_);
+}
+
+}  // namespace examples
+}  // namespace views