Use GestureDetector in WorkspaceTouchListener

Replace the current callback logic in WorkspaceTouchListener with the
use of GestureDetector.
That means, platform api is now going to be used for detecting long
press.

There now are some unused variables and unneeded code in this file. It
will be cleaned up in a follow-up CL.

Test: long press on empty home screen
Bug: 126596502
Change-Id: I57302b403f7d7118f2156166d8c707ab3f9ccefd

src/com/android/launcher3/touch/WorkspaceTouchListener.java

@@ -29,6 +29,7 @@ import android.graphics.Rect;
 import android.view.HapticFeedbackConstants;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.GestureDetector;
 import android.view.View.OnTouchListener;
 import android.view.ViewConfiguration;
 
@@ -45,7 +46,7 @@ import com.android.launcher3.userevent.nano.LauncherLogProto.ContainerType;
 /**
  * Helper class to handle touch on empty space in workspace and show options popup on long press
  */
-public class WorkspaceTouchListener implements OnTouchListener, Runnable {
+public class WorkspaceTouchListener extends GestureDetector.SimpleOnGestureListener implements OnTouchListener {
 
     /**
      * STATE_PENDING_PARENT_INFORM is the state between longPress performed & the next motionEvent.
@@ -66,16 +67,21 @@ public class WorkspaceTouchListener implements OnTouchListener, Runnable {
 
     private int mLongPressState = STATE_CANCELLED;
 
+    private final GestureDetector mGestureDetector;
+
     public WorkspaceTouchListener(Launcher launcher, Workspace workspace) {
         mLauncher = launcher;
         mWorkspace = workspace;
         // Use twice the touch slop as we are looking for long press which is more
         // likely to cause movement.
         mTouchSlop = 2 * ViewConfiguration.get(launcher).getScaledTouchSlop();
+        mGestureDetector = new GestureDetector(workspace.getContext(), this);
     }
 
     @Override
     public boolean onTouch(View view, MotionEvent ev) {
+        mGestureDetector.onTouchEvent(ev);
+
         int action = ev.getActionMasked();
         if (action == ACTION_DOWN) {
             // Check if we can handle long press.
@@ -97,7 +103,6 @@ public class WorkspaceTouchListener implements OnTouchListener, Runnable {
             if (handleLongPress) {
                 mLongPressState = STATE_REQUESTED;
                 mTouchDownPoint.set(ev.getX(), ev.getY());
-                mWorkspace.postDelayed(this, getLongPressTimeout());
             }
 
             mWorkspace.onTouchEvent(ev);
@@ -155,12 +160,11 @@ public class WorkspaceTouchListener implements OnTouchListener, Runnable {
     }
 
     private void cancelLongPress() {
-        mWorkspace.removeCallbacks(this);
         mLongPressState = STATE_CANCELLED;
     }
 
     @Override
-    public void run() {
+    public void onLongPress(MotionEvent event) {
         if (mLongPressState == STATE_REQUESTED) {
             if (canHandleLongPress()) {
                 mLongPressState = STATE_PENDING_PARENT_INFORM;