views_examples: add Button sticker sheet

ui/views/examples/button_sticker_sheet.cc

+// Copyright 2016 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 "ui/views/examples/button_sticker_sheet.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "ui/base/material_design/material_design_controller.h"
+#include "ui/views/controls/button/button.h"
+#include "ui/views/controls/button/md_text_button.h"
+#include "ui/views/layout/grid_layout.h"
+
+namespace views {
+namespace examples {
+
+namespace {
+
+// The id of the only ColumnSet in a stretchy grid (see below).
+const int kStretchyGridColumnSetId = 0;
+
+// Creates a stretchy grid layout: there are |ncols| columns, separated from
+// each other by padding columns, and all non-padding columns have equal flex
+// weight and will flex in either dimension as needed. The resulting grid layout
+// has only one ColumnSet (numbered kStretchyGridColumnSetId).
+GridLayout* MakeStretchyGridLayout(View* host, int ncols) {
+  const float kPaddingDoesNotResize = 0.0;
+  const int kPaddingWidth = 8;
+  const GridLayout::Alignment kColumnStretchesHorizontally = GridLayout::FILL;
+  const GridLayout::Alignment kColumnStretchesVertically = GridLayout::FILL;
+  const float kColumnResizesEqually = 1.0;
+  const GridLayout::SizeType kColumnUsesPreferredSize = GridLayout::USE_PREF;
+
+  GridLayout* layout = new GridLayout(host);
+  ColumnSet* columns = layout->AddColumnSet(kStretchyGridColumnSetId);
+  for (int i = 0; i < ncols; ++i) {
+    if (i != 0)
+      columns->AddPaddingColumn(kPaddingDoesNotResize, kPaddingWidth);
+    columns->AddColumn(kColumnStretchesHorizontally, kColumnStretchesVertically,
+                       kColumnResizesEqually, kColumnUsesPreferredSize, 0,
+                       0);  // These two are ignored when using PREF.
+  }
+  return layout;
+}
+
+View* MakePlainLabel(const std::string& text) {

[sky, 2016/09/02 14:31:19]

optional: I wouldn't bother with a one line function for this. It isn't really
buying you much.

+  return new Label(base::ASCIIToUTF16(text));
+}
+
+// Add a row containing a label whose text is |label_text| and then all the
+// views in |views| to the supplied GridLayout, with padding between rows.
+void AddLabelledRowToGridLayout(GridLayout* layout,
+                                const std::string& label_text,
+                                std::vector<View*> views) {
+  const float kRowDoesNotResizeVertically = 0.0;
+  const int kPaddingRowHeight = 8;
+  layout->StartRow(kRowDoesNotResizeVertically, kStretchyGridColumnSetId);
+  layout->AddView(MakePlainLabel(label_text));
+  for (const auto& view : views)
+    layout->AddView(view);
+  // This gets added extraneously after the last row, but it doesn't hurt and
+  // means there's no need to keep track of whether to add it or not.
+  layout->AddPaddingRow(kRowDoesNotResizeVertically, kPaddingRowHeight);
+}
+
+// Constructs a pair of MdTextButtons in the specified |state| with the
+// specified |listener|, and returns them in |*primary| and |*secondary|. The
+// button in |*primary| is a call-to-action button, and the button in
+// |*secondary| is a regular button.
+void MakeButtonsInState(MdTextButton** primary,
+                        MdTextButton** secondary,
+                        ButtonListener* listener,
+                        Button::ButtonState state) {
+  const base::string16 button_text = base::ASCIIToUTF16("Button");
+  *primary = MdTextButton::CreateMdButton(listener, button_text);
+  (*primary)->SetCallToAction(true);
+  (*primary)->SetState(state);
+
+  *secondary = MdTextButton::CreateMdButton(listener, button_text);
+  (*secondary)->SetState(state);
+}
+
+}  // namespace
+
+ButtonStickerSheet::ButtonStickerSheet()
+    : ExampleBase("Button (Sticker Sheet)") {}
+
+ButtonStickerSheet::~ButtonStickerSheet() {}
+
+void ButtonStickerSheet::CreateExampleView(View* container) {
+  GridLayout* layout = MakeStretchyGridLayout(container, 3);
+  container->SetLayoutManager(layout);
+
+  if (!ui::MaterialDesignController::IsSecondaryUiMaterial()) {
+    const char* kNeedsMdWarning =
+        "This will look wrong without --secondary-ui-md.";
+    layout->StartRow(0, 0);
+    layout->AddView(MakePlainLabel(kNeedsMdWarning), 3, 1);
+  }
+
+  // The title row has an empty row label.
+  AddLabelledRowToGridLayout(
+      layout, std::string(),
+      {MakePlainLabel("Primary"), MakePlainLabel("Secondary")});
+
+  MdTextButton* primary = nullptr;
+  MdTextButton* secondary = nullptr;
+
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_NORMAL);
+  AddLabelledRowToGridLayout(layout, "Default", {primary, secondary});
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_NORMAL);
+  AddLabelledRowToGridLayout(layout, "Normal", {primary, secondary});
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_HOVERED);
+  AddLabelledRowToGridLayout(layout, "Hovered", {primary, secondary});
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_PRESSED);
+  AddLabelledRowToGridLayout(layout, "Pressed", {primary, secondary});
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_DISABLED);
+  AddLabelledRowToGridLayout(layout, "Disabled", {primary, secondary});
+
+  MakeButtonsInState(&primary, &secondary, this, Button::STATE_NORMAL);
+  primary->OnFocus();
+  secondary->OnFocus();
+  AddLabelledRowToGridLayout(layout, "Focused", {primary, secondary});
+}
+
+void ButtonStickerSheet::ButtonPressed(Button* button, const ui::Event& event) {
+  // Ignore button presses.
+}
+
+}  // namespace examples
+}  // namespace views