New InputMethod api for Views.

views/ime/input_method_base.h

+// 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.
+
+#ifndef VIEWS_IME_INPUT_METHOD_BASE_H_
+#define VIEWS_IME_INPUT_METHOD_BASE_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "views/focus/focus_manager.h"
+#include "views/ime/input_method.h"
+#include "views/ime/input_method_delegate.h"
+#include "views/ime/text_input_client.h"
+
+namespace views {
+
+class View;
+
+// A helper class providing functionalities shared among InputMethod
+// implementations.
+class InputMethodBase : public InputMethod,
+                        public FocusChangeListener {
+ public:
+  InputMethodBase();
+  virtual ~InputMethodBase();
+
+  // Overriden from InputMethod.
+  virtual void set_delegate(internal::InputMethodDelegate* delegate) OVERRIDE;
+
+  // If a derived class overrides this method, it should call parent's
+  // implementation first.
+  virtual void Init(Widget* widget) OVERRIDE;
+
+  // Overridden from FocusChangeListener. Derived classes shouldn't override
+  // this method. Override FocusedViewWillChange() and FocusedViewDidChange()
+  // instead.
+  virtual void FocusWillChange(View* focused_before, View* focused) OVERRIDE;
+
+ protected:
+  // Getters and setters of properties.
+  internal::InputMethodDelegate* delegate() const { return delegate_; }
+  Widget* widget() const { return widget_; }
+  View* focused_view() const { return focused_view_; }
+
+  // Derived classes should call this method to update Widget's focus state when
+  // the Widget gets or loses keyboard focus.
+  void set_widget_focused(bool focused) { widget_focused_ = focused; }
+  bool widget_focused() const { return widget_focused_; }
+
+  // Checks if the given View is focused. Returns true only if the View and
+  // the Widget are both focused.
+  bool IsViewFocused(View* view) const;
+
+  // Gets the focused text input client. Returns NULL if the Widget is not
+  // focused, or there is no focused View or the focused View doesn't support
+  // text input.
+  TextInputClient* GetTextInputClient() const;
+
+  // Gets the text input type of the focused text input client. Returns
+  // ui::TEXT_INPUT_TYPE_NONE if there is no focused text input client.
+  ui::TextInputType GetTextInputType() const;
+
+  // Checks if the focused text input client's text input type is
+  // ui::TEXT_INPUT_TYPE_NONE. Also returns true if there is no focused text
+  // input client.
+  bool IsTextInputTypeNone() const;
+
+  // Convenience method to call the focused text input client's
+  // OnInputMethodChanged() method. It'll only take effect if the current text
+  // input type is not ui::TEXT_INPUT_TYPE_NONE.
+  void OnInputMethodChanged() const;
+
+  // Convenience method to call delegate_->DispatchKeyEventPostIME().
+  void DispatchKeyEventPostIME(const KeyEvent& key) const;
+
+  // Gets the current text input client's caret bounds in Widget's coordinates.
+  // Returns false if the current text input client doesn't support text input.
+  bool GetCaretBoundsInWidget(gfx::Rect* rect) const;
+
+  // Called just before changing the focused view. Should be overridden by
+  // derived classes. The default implementation does nothing.
+  virtual void FocusedViewWillChange();
+
+  // Called just after changing the focused view. Should be overridden by
+  // derived classes. The default implementation does nothing.
+  // Note: It's called just after changing the value of |focused_view_|. As it's
+  // called inside FocusChangeListener's FocusWillChange() method, which is
+  // called by the FocusManager before actually changing the focus, the derived
+  // class should not rely on the actual focus state of the |focused_view_|.
+  virtual void FocusedViewDidChange();
+
+ private:
+  internal::InputMethodDelegate* delegate_;
+  Widget* widget_;
+  View* focused_view_;
+
+  // Indicates if the top-level widget is focused or not.
+  bool widget_focused_;
+
+  DISALLOW_COPY_AND_ASSIGN(InputMethodBase);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_IME_INPUT_METHOD_BASE_H_