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-rw-r--r--services/accessibility/java/com/android/server/accessibility/AccessibilityGestureDetector.java138
1 files changed, 66 insertions, 72 deletions
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityGestureDetector.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityGestureDetector.java
index 912e8e2eb246..b79a7ba69b4e 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityGestureDetector.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityGestureDetector.java
@@ -25,6 +25,7 @@ import android.gesture.GestureStore;
import android.gesture.GestureStroke;
import android.gesture.Prediction;
import android.util.Slog;
+import android.util.TypedValue;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.VelocityTracker;
@@ -70,7 +71,7 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
// Indicates that we've collected enough data to be sure it could be a
// gesture.
- private boolean mGestureConfirmed;
+ private boolean mGestureStarted;
// Indicates that motion events from the second pointer are being checked
// for a double tap.
@@ -83,47 +84,39 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
// Policy flags of the previous event.
private int mPolicyFlags;
- // The X of the previous event.
- private float mPreviousX;
+ // These values track the previous point that was saved to use for gesture
+ // detection. They are only updated when the user moves more than the
+ // recognition threshold.
+ private float mPreviousGestureX;
+ private float mPreviousGestureY;
- // The Y of the previous event.
- private float mPreviousY;
-
- // The X of the down event.
+ // These values track the previous point that was used to determine if there
+ // was a transition into or out of gesture detection. They are updated when
+ // the user moves more than the detection threshold.
private float mBaseX;
-
- // The Y of the down event.
private float mBaseY;
+ private long mBaseTime;
- // Slop between the first and second tap to be a double tap.
- private final int mDoubleTapSlop;
-
- // The scaled velocity above which we detect gestures.
- private final int mScaledGestureDetectionVelocity;
+ // This is the calculated movement threshold used track if the user is still
+ // moving their finger.
+ private final float mGestureDetectionThreshold;
// Buffer for storing points for gesture detection.
private final ArrayList<GesturePoint> mStrokeBuffer = new ArrayList<GesturePoint>(100);
- // Helper to track gesture velocity.
- private final VelocityTracker mVelocityTracker = VelocityTracker.obtain();
-
// The minimal delta between moves to add a gesture point.
private static final int TOUCH_TOLERANCE = 3;
// The minimal score for accepting a predicted gesture.
private static final float MIN_PREDICTION_SCORE = 2.0f;
- // The velocity above which we detect gestures. Expressed in DIPs/Second.
- private static final int GESTURE_DETECTION_VELOCITY_DIP = 1000;
-
- // Constant used to calculate velocity in seconds.
- private static final int VELOCITY_UNITS_SECONDS = 1000;
+ private static final int GESTURE_CONFIRM_MM = 10;
+ private static final long CANCEL_ON_PAUSE_THRESHOLD_STARTED_MS = 1000;
+ private static final long CANCEL_ON_PAUSE_THRESHOLD_NOT_STARTED_MS = 500;
AccessibilityGestureDetector(Context context, Listener listener) {
mListener = listener;
- mDoubleTapSlop = ViewConfiguration.get(context).getScaledDoubleTapSlop();
-
mGestureDetector = new GestureDetector(context, this);
mGestureDetector.setOnDoubleTapListener(this);
@@ -132,15 +125,14 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
mGestureLibrary.setSequenceType(GestureStore.SEQUENCE_SENSITIVE);
mGestureLibrary.load();
- final float density = context.getResources().getDisplayMetrics().density;
- mScaledGestureDetectionVelocity = (int) (GESTURE_DETECTION_VELOCITY_DIP * density);
+ mGestureDetectionThreshold = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_MM, 1,
+ context.getResources().getDisplayMetrics()) * GESTURE_CONFIRM_MM;
}
public boolean onMotionEvent(MotionEvent event, int policyFlags) {
- mVelocityTracker.addMovement(event);
-
final float x = event.getX();
final float y = event.getY();
+ final long time = event.getEventTime();
mPolicyFlags = policyFlags;
switch (event.getActionMasked()) {
@@ -148,54 +140,56 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
mDoubleTapDetected = false;
mSecondFingerDoubleTap = false;
mRecognizingGesture = true;
- mGestureConfirmed = false;
+ mGestureStarted = false;
+ mPreviousGestureX = x;
+ mPreviousGestureY = y;
+ mStrokeBuffer.clear();
+ mStrokeBuffer.add(new GesturePoint(x, y, time));
+
mBaseX = x;
mBaseY = y;
- mPreviousX = x;
- mPreviousY = y;
- mStrokeBuffer.clear();
- mStrokeBuffer.add(new GesturePoint(x, y, event.getEventTime()));
- mVelocityTracker.clear();
- mVelocityTracker.addMovement(event);
+ mBaseTime = time;
break;
case MotionEvent.ACTION_MOVE:
if (mRecognizingGesture) {
- if (!mGestureConfirmed) {
- mVelocityTracker.addMovement(event);
- // It is *important* to use the distance traveled by the pointers
- // on the screen which may or may not be magnified.
- final float deltaX = mBaseX - event.getX(0);
- final float deltaY = mBaseY - event.getY(0);
- final double moveDelta = Math.hypot(deltaX, deltaY);
- // The user has moved enough for us to decide.
- if (moveDelta > mDoubleTapSlop) {
- // Check whether the user is performing a gesture. We
- // detect gestures if the pointer is moving above a
- // given velocity.
- mVelocityTracker.computeCurrentVelocity(VELOCITY_UNITS_SECONDS);
- final float maxAbsVelocity = Math.max(
- Math.abs(mVelocityTracker.getXVelocity(0)),
- Math.abs(mVelocityTracker.getYVelocity(0)));
- if (maxAbsVelocity > mScaledGestureDetectionVelocity) {
- // We have to perform gesture detection, so
- // notify the listener.
- mGestureConfirmed = true;
- mListener.onGestureStarted();
- } else {
- // This won't match any gesture, so notify the
- // listener.
- cancelGesture();
- mListener.onGestureCancelled(event, policyFlags);
- }
+ final float deltaX = mBaseX - x;
+ final float deltaY = mBaseY - y;
+ final double moveDelta = Math.hypot(deltaX, deltaY);
+ if (moveDelta > mGestureDetectionThreshold) {
+ // If the pointer has moved more than the threshold,
+ // update the stored values.
+ mBaseX = x;
+ mBaseY = y;
+ mBaseTime = time;
+
+ // If this hasn't been confirmed as a gesture yet, send
+ // the event.
+ if (!mGestureStarted) {
+ mGestureStarted = true;
+ mListener.onGestureStarted();
+ }
+ } else {
+ final long timeDelta = time - mBaseTime;
+ final long threshold = mGestureStarted ?
+ CANCEL_ON_PAUSE_THRESHOLD_STARTED_MS :
+ CANCEL_ON_PAUSE_THRESHOLD_NOT_STARTED_MS;
+
+ // If the pointer hasn't moved for longer than the
+ // timeout, cancel gesture detection.
+ if (timeDelta > threshold) {
+ cancelGesture();
+ mListener.onGestureCancelled(event, policyFlags);
+ return false;
}
}
- final float dX = Math.abs(x - mPreviousX);
- final float dY = Math.abs(y - mPreviousY);
+
+ final float dX = Math.abs(x - mPreviousGestureX);
+ final float dY = Math.abs(y - mPreviousGestureY);
if (dX >= TOUCH_TOLERANCE || dY >= TOUCH_TOLERANCE) {
- mPreviousX = x;
- mPreviousY = y;
- mStrokeBuffer.add(new GesturePoint(x, y, event.getEventTime()));
+ mPreviousGestureX = x;
+ mPreviousGestureY = y;
+ mStrokeBuffer.add(new GesturePoint(x, y, time));
}
}
break;
@@ -204,8 +198,8 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
if (maybeFinishDoubleTap(event, policyFlags)) {
return true;
}
- if (mGestureConfirmed) {
- mStrokeBuffer.add(new GesturePoint(x, y, event.getEventTime()));
+ if (mGestureStarted) {
+ mStrokeBuffer.add(new GesturePoint(x, y, time));
if (!recognizeGesture()) {
mListener.onGestureCancelled(event, policyFlags);
@@ -223,7 +217,7 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
// If this was the second finger, attempt to recognize double
// taps on it.
mSecondFingerDoubleTap = true;
- mSecondPointerDownTime = event.getEventTime();
+ mSecondPointerDownTime = time;
} else {
// If there are more than two fingers down, stop watching
// for a double tap.
@@ -268,8 +262,8 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
mFirstTapDetected = false;
mDoubleTapDetected = false;
mSecondFingerDoubleTap = false;
+ mGestureStarted = false;
cancelGesture();
- mVelocityTracker.clear();
}
public boolean firstTapDetected() {
@@ -323,7 +317,7 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
private void cancelGesture() {
mRecognizingGesture = false;
- mGestureConfirmed = false;
+ mGestureStarted = false;
mStrokeBuffer.clear();
}
generated by cgit v1.2.3-59-g8ed1b (git 2.39.0) at 2025-12-02 04:43:18 +0000