BoxLayout now suports per-view margins.

ui/views/examples/box_layout_example.cc

Index: ui/views/examples/box_layout_example.cc
diff --git a/ui/views/examples/box_layout_example.cc b/ui/views/examples/box_layout_example.cc
new file mode 100644
index 0000000000000000000000000000000000000000..39f087a08ed6ce9d4106ce76f4fda9a44d324390
--- /dev/null
+++ b/ui/views/examples/box_layout_example.cc
@@ -0,0 +1,419 @@
+// Copyright (c) 2017 The Chromium Authors. All rights reserved.

[sky, 2017/05/09 19:26:02]

no (c)

+// 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 "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/layout/fill_layout.h"
+#include "ui/views/view.h"
+
+namespace views {
+namespace examples {
+
+namespace {
+
+class FullPanel : public View {

[sky, 2017/05/09 19:26:02]

Please add comments for classes. This name is confusing as I would naively
expect the children to be given the full bounds, which isn't the case. Also,
more often than not we use View in the name rather than panel.

[kylix_rd, 2017/05/10 15:30:36]

Done.

+ public:
+  FullPanel() {}
+  ~FullPanel() override {}
+
+  void Layout() override;

[sky, 2017/05/09 19:26:03]

Prefix with where override comes from.

[kylix_rd, 2017/05/10 15:30:36]

Done.

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FullPanel);
+};
+
+class ChildPanel : public View, public TextfieldController {
+ public:
+  ChildPanel(BoxLayoutExample* example);

[sky, 2017/05/09 19:26:02]

explicit.

[kylix_rd, 2017/05/10 15:30:36]

Done.

+  ~ChildPanel() override {}
+
+  // View
+  gfx::Size GetPreferredSize() const override;
+  bool OnMousePressed(const ui::MouseEvent& event) override;
+  void Layout() override;
+
+  void set_listener(ViewListener* listener) { listener_ = listener; }
+  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;
+  ViewListener* listener_ = nullptr;
+  Textfield* flex_;
+  Textfield* margin_[4];
+
+  DISALLOW_COPY_AND_ASSIGN(ChildPanel);
+};
+
+class ExampleModel : public ui::ComboboxModel {

[sky, 2017/05/09 19:26:03]

Can you use ui/views/examples/example_combobox_model.h ?

[kylix_rd, 2017/05/10 15:30:36]

Yep. I didn't notice it was there.

Done.

+ public:
+  ExampleModel(const std::initializer_list<base::string16>& items)
+      : ui::ComboboxModel(), items_(items) {}
+  ~ExampleModel() override {}
+  // ComboboxModel

[sky, 2017/05/09 19:26:02]

newline between 78/79.

+  int GetItemCount() const override { return items_.size(); }
+
+  base::string16 GetItemAt(int index) override { return items_[index]; }
+
+ private:
+  std::vector<base::string16> items_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExampleModel);
+};
+
+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(L"");
+}
+
+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);
+        }
+      }
+      if (listener_)
+        listener_->ViewSelected(this);
+    }
+    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(L"0");
+  textfield->set_controller(this);
+  textfield->SetVisible(false);
+  AddChildView(textfield);
+  return textfield;
+}
+}
+
+BoxLayoutExample::BoxLayoutExample() : ExampleBase("Box Layout") {}
+
+BoxLayoutExample::~BoxLayoutExample() {}
+
+void BoxLayoutExample::CreateExampleView(View* container) {
+  const int kSpacing = 5;
+  const int kPadding = 8;
+  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 = kPadding;
+  add_button_ = MdTextButton::CreateSecondaryUiButton(this, L"Add");
+  add_button_->SetPosition(gfx::Point(kPadding, vertical_pos));
+  add_button_->SizeToPreferredSize();
+  control_panel_->AddChildView(add_button_);
+  vertical_pos += add_button_->height() + kSpacing;
+
+  Label* label = new Label(L"Orientation");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  orientation_ = new Combobox(base::MakeUnique<ExampleModel>(
+      std::initializer_list<base::string16>({L"Horizontal", L"Vertical"})));
+  orientation_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  orientation_->SizeToPreferredSize();
+  orientation_->set_listener(this);
+  label->SetSize(gfx::Size(label->width(), orientation_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(orientation_);
+  vertical_pos += orientation_->height() + kSpacing;
+
+  label = new Label(L"Main axis");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  main_axis_alignment_ = new Combobox(base::MakeUnique<ExampleModel>(
+      std::initializer_list<base::string16>({L"Start", L"Center", L"End"})));
+  main_axis_alignment_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  main_axis_alignment_->SizeToPreferredSize();
+  main_axis_alignment_->set_listener(this);
+  label->SetSize(gfx::Size(label->width(), main_axis_alignment_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(main_axis_alignment_);
+  vertical_pos += main_axis_alignment_->height() + kSpacing;
+
+  label = new Label(L"Cross axis");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  cross_axis_alignment_ = new Combobox(
+      base::MakeUnique<ExampleModel>(std::initializer_list<base::string16>(
+          {L"Stretch", L"Start", L"Center", L"End"})));
+  cross_axis_alignment_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  cross_axis_alignment_->SizeToPreferredSize();
+  cross_axis_alignment_->set_listener(this);
+  label->SetSize(gfx::Size(label->width(), cross_axis_alignment_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(cross_axis_alignment_);
+  vertical_pos += cross_axis_alignment_->height() + kSpacing;
+
+  label = new Label(L"Child spacing");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  between_child_spacing_ = new Textfield();
+  between_child_spacing_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  between_child_spacing_->set_default_width_in_chars(3);
+  between_child_spacing_->SetTextInputType(ui::TEXT_INPUT_TYPE_NUMBER);
+  between_child_spacing_->SizeToPreferredSize();
+  between_child_spacing_->SetText(L"0");
+  between_child_spacing_->set_controller(this);
+  label->SetSize(gfx::Size(label->width(), between_child_spacing_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(between_child_spacing_);
+  vertical_pos += between_child_spacing_->height() + kSpacing;
+
+  label = new Label(L"Default flex");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  default_flex_ = new Textfield();
+  default_flex_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  default_flex_->set_default_width_in_chars(3);
+  default_flex_->SetTextInputType(ui::TEXT_INPUT_TYPE_NUMBER);
+  default_flex_->SizeToPreferredSize();
+  default_flex_->SetText(L"0");
+  default_flex_->set_controller(this);
+  label->SetSize(gfx::Size(label->width(), default_flex_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(default_flex_);
+  vertical_pos += default_flex_->height() + kSpacing;
+
+  label = new Label(L"Min cross axis");
+  label->SetPosition(gfx::Point(kPadding, vertical_pos));
+  label->SizeToPreferredSize();
+  min_cross_axis_size_ = new Textfield();
+  min_cross_axis_size_->SetPosition(
+      gfx::Point(label->x() + label->width() + kSpacing, vertical_pos));
+  min_cross_axis_size_->set_default_width_in_chars(3);
+  min_cross_axis_size_->SetTextInputType(ui::TEXT_INPUT_TYPE_NUMBER);
+  min_cross_axis_size_->SizeToPreferredSize();
+  min_cross_axis_size_->SetText(L"0");
+  min_cross_axis_size_->set_controller(this);
+  label->SetSize(gfx::Size(label->width(), min_cross_axis_size_->height()));
+  control_panel_->AddChildView(label);
+  control_panel_->AddChildView(min_cross_axis_size_);
+  vertical_pos += min_cross_axis_size_->height() + kSpacing;
+
+  collapse_margins_ = new Checkbox(L"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_ < 5) {
+      ++panel_count_;
+      ChildPanel* panel = new ChildPanel(this);
+      panel->set_listener(this);
+      panel->SetGroup(100);
+      box_layout_panel_->AddChildView(panel);
+      RefreshLayoutPanel();
+    } else {
+      PrintStatus("Only 5 panels may be added");
+    }
+  } 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::ViewSelected(View* view) {}
+
+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);
+  }
+  RefreshLayoutPanel();
+}
+
+void BoxLayoutExample::RefreshLayoutPanel() {
+  box_layout_panel_->Layout();
+  box_layout_panel_->SchedulePaint();
+}
+
+void BoxLayoutExample::UpdateLayoutManager() {
+  int child_spacing;
+  int default_flex;
+  int min_cross_size;
+  base::StringToInt(between_child_spacing_->text(), &child_spacing);

[sky, 2017/05/09 19:26:03]

Remember that conversion may fail and return false, in which case the field
isn't updated.

[kylix_rd, 2017/05/09 20:07:06]

According to the doc, errors will set |*output| to 0, which is fine in this
instance.

+  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);
+  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