The bigger touch slop still has a problem

I had submitted the patch about this issue at
https://android-review.googlesource.com/#/c/20438/ before. But it
has never been included in any version.

In the latest implementation, touchSlop is a configurable value
which is declared in config.xml for each device. First of all,
the problem is that BiggerTouchSlop is not scalable and variable
value according to a configured touchSlop.

I don't think that there should be a new api in ViewConfiguration
for this. Because the bigger touch slop is a local threshold value
in GestureDetector. The only thing to be satisfied is that the
value should be bigger than configured touch slop and should not
be over double touch slop.

Change-Id: I2c6662400fcffb4a7192ede4ac8da08559aa7948

Author: aiot-ogino

core/java/android/view/GestureDetector.java

@@ -193,8 +193,7 @@ public boolean onSingleTapConfirmed(MotionEvent e) {
         }
     }
 
-    // TODO: ViewConfiguration
-    private int mBiggerTouchSlopSquare = 20 * 20;
+    private int mBiggerTouchSlopSquare;
 
     private int mTouchSlopSquare;
     private int mDoubleTapSlopSquare;
@@ -408,6 +407,14 @@ private void init(Context context, boolean ignoreMultitouch) {
         }
         mTouchSlopSquare = touchSlop * touchSlop;
         mDoubleTapSlopSquare = doubleTapSlop * doubleTapSlop;
+
+        // The biggerTouchSlop should be a little bit bigger than touchSlop
+        // and mBiggerTouchSlopSquare should not be over mDoubleTapSlopSquare.
+        int biggerTouchSlop = (int)(touchSlop * 1.25f);
+        mBiggerTouchSlopSquare = biggerTouchSlop * biggerTouchSlop;
+        if (mBiggerTouchSlopSquare > mDoubleTapSlopSquare) {
+            mBiggerTouchSlopSquare = mDoubleTapSlopSquare;
+        }
     }
 
     /**