views/examples: Add ProgressBar example.

views/examples/progress_bar_example.cc

+// Copyright (c) 2011 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 "views/examples/progress_bar_example.h"
+
+#include "base/utf_string_conversions.h"
+#include "views/controls/button/text_button.h"
+#include "views/controls/progress_bar.h"
+#include "views/layout/grid_layout.h"
+#include "views/view.h"
+
+namespace {
+
+const double kStepSize = 0.1;
+
+double ClampToMin(double percent) {
+  return std::min(std::max(percent, 0.0), 1.0);
+}
+
+}  // namespace
+
+namespace examples {
+
+ProgressBarExample::ProgressBarExample(ExamplesMain* main)
+    : ExampleBase(main, "Progress Bar"),
+      minus_button_(NULL),
+      plus_button_(NULL),
+      progress_bar_(NULL),
+      current_percent_(0.0) {
+}
+
+ProgressBarExample::~ProgressBarExample() {
+}
+
+void ProgressBarExample::CreateExampleView(views::View* container) {
+  views::GridLayout* layout = new views::GridLayout(container);
+  container->SetLayoutManager(layout);
+
+  views::ColumnSet* column_set = layout->AddColumnSet(0);
+  column_set->AddColumn(views::GridLayout::LEADING, views::GridLayout::FILL,
+                        0, views::GridLayout::USE_PREF, 0, 0);
+  column_set->AddPaddingColumn(0, 8);
+  column_set->AddColumn(views::GridLayout::FILL, views::GridLayout::FILL,
+                        1, views::GridLayout::USE_PREF, 0, 0);
+  column_set->AddPaddingColumn(0, 8);
+  column_set->AddColumn(views::GridLayout::TRAILING, views::GridLayout::FILL,
+                        0, views::GridLayout::USE_PREF, 0, 0);
+
+  layout->StartRow(0, 0);
+  minus_button_ = new views::TextButton(this, ASCIIToUTF16("-"));
+  layout->AddView(minus_button_);
+  progress_bar_ = new views::ProgressBar();
+  layout->AddView(progress_bar_);
+  plus_button_ = new views::TextButton(this, ASCIIToUTF16("+"));
+  layout->AddView(plus_button_);
+}
+
+void ProgressBarExample::ButtonPressed(views::Button* sender,
+                                       const views::Event& event) {
+  if (sender == minus_button_)
+    current_percent_ = ClampToMin(current_percent_ - kStepSize);
+  else if (sender == plus_button_)
+    current_percent_ = ClampToMin(current_percent_ + kStepSize);
+
+  progress_bar_->SetValue(current_percent_);
+}
+
+}  // namespace examples