2 files changed, 34 insertions, 6 deletions

diff --git a/core/java/android/view/ScaleGestureDetector.java b/core/java/android/view/ScaleGestureDetector.java
index dc11d3ddd1d6..c24b8b2a5ee3 100644
--- a/core/java/android/view/ScaleGestureDetector.java
+++ b/core/java/android/view/ScaleGestureDetector.java
@@ -18,7 +18,6 @@ package android.view;
 
 import android.annotation.UnsupportedAppUsage;
 import android.content.Context;
-import android.content.res.Resources;
 import android.os.Build;
 import android.os.Handler;
 
@@ -145,7 +144,7 @@ public class ScaleGestureDetector {
     private boolean mInProgress;
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 123768938)
     private int mSpanSlop;
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 123768938)
     private int mMinSpan;
 
     private final Handler mHandler;
@@ -200,10 +199,9 @@ public class ScaleGestureDetector {
                                 Handler handler) {
         mContext = context;
         mListener = listener;
-        mSpanSlop = ViewConfiguration.get(context).getScaledTouchSlop() * 2;
-
-        final Resources res = context.getResources();
-        mMinSpan = res.getDimensionPixelSize(com.android.internal.R.dimen.config_minScalingSpan);
+        final ViewConfiguration viewConfiguration = ViewConfiguration.get(context);
+        mSpanSlop = viewConfiguration.getScaledTouchSlop() * 2;
+        mMinSpan = viewConfiguration.getScaledMinScalingSpan();
         mHandler = handler;
         // Quick scale is enabled by default after JB_MR2
         final int targetSdkVersion = context.getApplicationInfo().targetSdkVersion;
diff --git a/core/java/android/view/ViewConfiguration.java b/core/java/android/view/ViewConfiguration.java
index 6beae37d6b46..bb29ed6c5339 100644
--- a/core/java/android/view/ViewConfiguration.java
+++ b/core/java/android/view/ViewConfiguration.java
@@ -293,12 +293,14 @@ public class ViewConfiguration {
      */
     private static final float AMBIGUOUS_GESTURE_MULTIPLIER = 2f;
 
+    private final boolean mConstructedWithContext;
     private final int mEdgeSlop;
     private final int mFadingEdgeLength;
     private final int mMinimumFlingVelocity;
     private final int mMaximumFlingVelocity;
     private final int mScrollbarSize;
     private final int mTouchSlop;
+    private final int mMinScalingSpan;
     private final int mHoverSlop;
     private final int mMinScrollbarTouchTarget;
     private final int mDoubleTapTouchSlop;
@@ -329,6 +331,7 @@ public class ViewConfiguration {
      */
     @Deprecated
     public ViewConfiguration() {
+        mConstructedWithContext = false;
         mEdgeSlop = EDGE_SLOP;
         mFadingEdgeLength = FADING_EDGE_LENGTH;
         mMinimumFlingVelocity = MINIMUM_FLING_VELOCITY;
@@ -350,6 +353,10 @@ public class ViewConfiguration {
         mHorizontalScrollFactor = HORIZONTAL_SCROLL_FACTOR;
         mVerticalScrollFactor = VERTICAL_SCROLL_FACTOR;
         mShowMenuShortcutsWhenKeyboardPresent = false;
+
+        // Getter throws if mConstructedWithContext is false so doesn't matter what
+        // this value is.
+        mMinScalingSpan = 0;
     }
 
     /**
@@ -363,6 +370,7 @@ public class ViewConfiguration {
      * @see android.util.DisplayMetrics
      */
     private ViewConfiguration(Context context) {
+        mConstructedWithContext = true;
         final Resources res = context.getResources();
         final DisplayMetrics metrics = res.getDisplayMetrics();
         final Configuration config = res.getConfiguration();
@@ -447,6 +455,8 @@ public class ViewConfiguration {
         mShowMenuShortcutsWhenKeyboardPresent = res.getBoolean(
             com.android.internal.R.bool.config_showMenuShortcutsWhenKeyboardPresent);
 
+        mMinScalingSpan = res.getDimensionPixelSize(
+                com.android.internal.R.dimen.config_minScalingSpan);
     }
 
     /**
@@ -959,6 +969,26 @@ public class ViewConfiguration {
     }
 
     /**
+     * Retrieves the distance in pixels between touches that must be reached for a gesture to be
+     * interpreted as scaling.
+     *
+     * In general, scaling shouldn't start until this distance has been met or surpassed, and
+     * scaling should end when the distance in pixels between touches drops below this distance.
+     *
+     * @return The distance in pixels
+     * @throws IllegalStateException if this method is called on a ViewConfiguration that was
+     *         instantiated using a constructor with no Context parameter.
+     */
+    public int getScaledMinScalingSpan() {
+        if (!mConstructedWithContext) {
+            throw new IllegalStateException("Min scaling span cannot be determined when this "
+                    + "method is called on a ViewConfiguration that was instantiated using a "
+                    + "constructor with no Context parameter");
+        }
+        return mMinScalingSpan;
+    }
+
+    /**
      * @hide
      * @return Whether or not marquee should use fading edges.
      */