From 85f9f501b184e09a8f5e99ecbd2c35ba93a6bffd Mon Sep 17 00:00:00 2001
From: Charles Chen <charlesccchen@google.com>
Date: Tue, 26 May 2020 16:52:05 +0800
Subject: [PATCH] Add an incorrect context violation on GestureDetector

Also update the documentation of GestureDetector ctr.

fixes: 157165393
Test: build & run
Change-Id: If87d78d7337d7926af0a37819e4365a216a978b2
---
 core/java/android/view/GestureDetector.java | 26 ++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/core/java/android/view/GestureDetector.java b/core/java/android/view/GestureDetector.java
index f6c72c4eefbc9..55c527ba6fa68 100644
--- a/core/java/android/view/GestureDetector.java
+++ b/core/java/android/view/GestureDetector.java
@@ -16,6 +16,8 @@
 
 package android.view;
 
+import static android.os.StrictMode.vmIncorrectContextUseEnabled;
+
 import static com.android.internal.util.FrameworkStatsLog.TOUCH_GESTURE_CLASSIFIED__CLASSIFICATION__DEEP_PRESS;
 import static com.android.internal.util.FrameworkStatsLog.TOUCH_GESTURE_CLASSIFIED__CLASSIFICATION__DOUBLE_TAP;
 import static com.android.internal.util.FrameworkStatsLog.TOUCH_GESTURE_CLASSIFIED__CLASSIFICATION__LONG_PRESS;
@@ -26,9 +28,12 @@ import static com.android.internal.util.FrameworkStatsLog.TOUCH_GESTURE_CLASSIFI
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.os.Build;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
+import android.os.StrictMode;
 import android.os.SystemClock;
+import android.util.Log;
 
 import com.android.internal.util.FrameworkStatsLog;
 
@@ -228,6 +233,7 @@ public class GestureDetector {
         }
     }
 
+    private static final String TAG = GestureDetector.class.getSimpleName();
     @UnsupportedAppUsage
     private int mTouchSlopSquare;
     private int mDoubleTapTouchSlopSquare;
@@ -378,7 +384,8 @@ public class GestureDetector {
      * You may only use this constructor from a {@link android.os.Looper} thread.
      * @see android.os.Handler#Handler()
      *
-     * @param context the application's context
+     * @param context An {@link android.app.Activity} or a {@link Context} created from
+     * {@link Context#createWindowContext(int, Bundle)}
      * @param listener the listener invoked for all the callbacks, this must
      * not be null. If the listener implements the {@link OnDoubleTapListener} or
      * {@link OnContextClickListener} then it will also be set as the listener for
@@ -395,7 +402,8 @@ public class GestureDetector {
      * thread associated with the supplied {@link android.os.Handler}.
      * @see android.os.Handler#Handler()
      *
-     * @param context the application's context
+     * @param context An {@link android.app.Activity} or a {@link Context} created from
+     * {@link Context#createWindowContext(int, Bundle)}
      * @param listener the listener invoked for all the callbacks, this must
      * not be null. If the listener implements the {@link OnDoubleTapListener} or
      * {@link OnContextClickListener} then it will also be set as the listener for
@@ -425,7 +433,8 @@ public class GestureDetector {
      * thread associated with the supplied {@link android.os.Handler}.
      * @see android.os.Handler#Handler()
      *
-     * @param context the application's context
+     * @param context An {@link android.app.Activity} or a {@link Context} created from
+     * {@link Context#createWindowContext(int, Bundle)}
      * @param listener the listener invoked for all the callbacks, this must
      * not be null.
      * @param handler the handler to use for running deferred listener events.
@@ -456,6 +465,17 @@ public class GestureDetector {
             mMaximumFlingVelocity = ViewConfiguration.getMaximumFlingVelocity();
             mAmbiguousGestureMultiplier = ViewConfiguration.getAmbiguousGestureMultiplier();
         } else {
+            if (!context.isUiContext() && vmIncorrectContextUseEnabled()) {
+                final String errorMessage =
+                        "Tried to access UI constants from a non-visual Context.";
+                final String message = "GestureDetector must be accessed from Activity or other "
+                        + "visual Context. Use an Activity or a Context created with "
+                        + "Context#createWindowContext(int, Bundle), which are adjusted to the "
+                        + "configuration and visual bounds of an area on screen.";
+                final Exception exception = new IllegalArgumentException(errorMessage);
+                StrictMode.onIncorrectContextUsed(message, exception);
+                Log.e(TAG, errorMessage + message, exception);
+            }
             final ViewConfiguration configuration = ViewConfiguration.get(context);
             touchSlop = configuration.getScaledTouchSlop();
             doubleTapTouchSlop = configuration.getScaledDoubleTapTouchSlop();