[Remoting Android] Refactor GlDesktopView

remoting/android/java/src/org/chromium/chromoting/DesktopView.java

 // Copyright 2013 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.
 
 package org.chromium.chromoting;
 
 import android.content.Context;
-import android.graphics.Matrix;
-import android.graphics.PointF;
 import android.text.InputType;
+import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.SurfaceView;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
 import android.view.inputmethod.InputMethodManager;
 
 import org.chromium.chromoting.jni.Client;
 
 /**
- * The abstract class for viewing and interacting with a specific remote host. Handles logic
- * for touch input and render data.
+ * The class for viewing and interacting with a specific remote host.

[joedow, 2016/09/12 19:55:08]

IIUC the lifetime for this class is longer than the current activity, if so then
I think a comment should be added to describe the lifetime of an instance of
this class as well as the expectations that users of it should have (i.e. attach
when the view is created and call detach when the view is destroyed).

[Yuwei, 2016/09/12 20:57:18]

I think it should be roughly the same as the activity?

[joedow, 2016/09/12 21:01:56]

It would be good to confirm and document.  I had assumed it would outlive the
activity (which is destroyed for events such as rotation changes) since the view
attaches/detaches when it is created/destroyed.

[Yuwei, 2016/09/12 22:17:57]

Confirm that it's recreated when the activity is recreated. Added some comments
about the lifetime.
It was basically like "attaching the view to the RenderStub" and "detaching the
view from the RenderStub".

I've changed the design a little bit. I override the view's attach/detach
function to do these things.

  */
-public abstract class DesktopView extends SurfaceView {
-
-    protected final TouchInputHandler mInputHandler;
-
-    /**
-     * Subclass should trigger this event when the client view size is changed.
-     */
-    protected final Event.Raisable<SizeChangedEventParameter> mOnClientSizeChanged =
-            new Event.Raisable<>();
-
-    /**
-     * Subclass should trigger this event when the host (desktop frame) size is changed.
-     */
-    protected final Event.Raisable<SizeChangedEventParameter> mOnHostSizeChanged =
-            new Event.Raisable<>();
-
-    /**
-     * Subclass should trigger this event when a frame is rendered.
-     */
-    protected final Event.Raisable<Void> mOnCanvasRendered = new Event.Raisable<>();
-
-    /** The parent Desktop activity. */
-    private final Desktop mDesktop;
+public class DesktopView extends SurfaceView {
 
     private final Event.Raisable<TouchEventParameter> mOnTouch = new Event.Raisable<>();
 
-    public DesktopView(Desktop desktop, Client client) {
-        super(desktop);
-        Preconditions.notNull(desktop);
-        Preconditions.notNull(client);
-        mDesktop = desktop;
-        mInputHandler = new TouchInputHandler(this, desktop);
-        mInputHandler.init(desktop, new InputEventSender(client));
+    /** The parent Desktop activity. */
+    private Desktop mDesktop;
+
+    private TouchInputHandler mInputHandler;
+
+    public DesktopView(Context context, AttributeSet attributeSet) {
+        super(context, attributeSet);
 
         // Give this view keyboard focus, allowing us to customize the soft keyboard's settings.
         setFocusableInTouchMode(true);
     }
 
+    /**
+     * Initializes the view and attaches listeners to RenderStub's events. The desktop view can
+     * only be attached once at a time.
+     */
+    public void attach(Client client, Desktop desktop, RenderStub renderStub) {
+        Preconditions.isNull(mDesktop);
+        Preconditions.notNull(desktop);
+        mDesktop = desktop;
+        renderStub.setDesktopView(this);
+        mInputHandler = new TouchInputHandler(this, desktop, renderStub,
+                new InputEventSender(client));
+    }
+
+    /**
+     * Detaches listeners from the RenderStub's events. The desktop view must have been attached
+     * when calling this function.

[joedow, 2016/09/12 19:55:08]

nit: s/when/prior to

[Yuwei, 2016/09/12 22:17:58]

Obsolete.

+     */
+    public void detach() {
+        Preconditions.notNull(mDesktop);
+        mInputHandler.detach();
+    }
+
     // TODO(yuweih): move showActionBar and showKeyboard out of this abstract class.
     /** Shows the action bar. */
     public final void showActionBar() {
         mDesktop.showSystemUi();
     }
 
     /** Shows the software keyboard. */
     public final void showKeyboard() {
         InputMethodManager inputManager =
                 (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
         inputManager.showSoftInput(this, 0);
     }
 
     /** An {@link Event} which is triggered when user touches the screen. */
     public final Event<TouchEventParameter> onTouch() {
         return mOnTouch;
     }
 
-    /** An {@link Event} which is triggered when the client size is changed. */
-    public final Event<SizeChangedEventParameter> onClientSizeChanged() {
-        return mOnClientSizeChanged;
-    }
-
-    /** An {@link Event} which is triggered when the host size is changed. */
-    public final Event<SizeChangedEventParameter> onHostSizeChanged() {
-        return mOnHostSizeChanged;
-    }
-
-    /** An {@link Event} which is triggered when a frame is rendered. */
-    public final Event<Void> onCanvasRendered() {
-        return mOnCanvasRendered;
-    }
-
-    // View overrides.
     /** Called when a software keyboard is requested, and specifies its options. */
     @Override
     public final InputConnection onCreateInputConnection(EditorInfo outAttrs) {
         // Disables rich input support and instead requests simple key events.
         outAttrs.inputType = InputType.TYPE_NULL;
 
         // Prevents most third-party IMEs from ignoring our Activity's adjustResize preference.
         outAttrs.imeOptions |= EditorInfo.IME_FLAG_NO_FULLSCREEN;
 
         // Ensures that keyboards will not decide to hide the remote desktop on small displays.
         outAttrs.imeOptions |= EditorInfo.IME_FLAG_NO_EXTRACT_UI;
 
         // Stops software keyboards from closing as soon as the enter key is pressed.
         outAttrs.imeOptions |= EditorInfo.IME_MASK_ACTION | EditorInfo.IME_FLAG_NO_ENTER_ACTION;
 
         return null;
     }
 
     /** Called whenever the user attempts to touch the canvas. */
     @Override
     public final boolean onTouchEvent(MotionEvent event) {
         TouchEventParameter parameter = new TouchEventParameter(event);
         mOnTouch.raise(parameter);
         return parameter.handled;
     }
-
-    /** Triggers a brief animation to indicate the existence and location of an input event. */
-    public abstract void showInputFeedback(RenderStub.InputFeedbackType feedbackToShow, PointF pos);
-
-    /**
-     * Informs the view that its transformation matrix (for rendering the remote desktop bitmap)
-     * has been changed by the TouchInputHandler, which requires repainting.
-     */
-    public abstract void transformationChanged(Matrix matrix);
-
-    /**
-     * Informs the view that the cursor has been moved by the TouchInputHandler, which requires
-     * repainting.
-     */
-    public abstract void cursorMoved(PointF position);
-
-    /**
-     * Informs the view that the cursor visibility has been changed (for different input mode) by
-     * the TouchInputHandler, which requires repainting.
-     */
-    public abstract void cursorVisibilityChanged(boolean visible);
 }