| /* |
| * Copyright 2022 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.input.motionprediction; |
| |
| import android.view.MotionEvent; |
| import android.view.View; |
| |
| import androidx.annotation.NonNull; |
| import androidx.annotation.Nullable; |
| import androidx.input.motionprediction.kalman.KalmanMotionEventPredictor; |
| |
| /** |
| * There is a gap between the time a user touches the screen and that information is reported to the |
| * app; a motion predictor is a utility that provides predicted {@link android.view.MotionEvent} |
| * based on the previously received ones. Obtain a new predictor instance using |
| * {@link #newInstance(android.view.View)}; put the motion events you receive into it with |
| * {@link #recordMovement(android.view.MotionEvent)}, and call {@link #predict()} to retrieve the |
| * predicted {@link android.view.MotionEvent} that would occur at the moment the next frame is |
| * rendered on the display. Once no more predictions are needed, call {@link #dispose()} to stop it |
| * and clean up resources. |
| */ |
| public interface MotionEventPredictor { |
| /** |
| * Record a user's movement to the predictor. You should call this for every |
| * {@link android.view.MotionEvent} that is received by the associated |
| * {@link android.view.View}. |
| * @param event the {@link android.view.MotionEvent} the associated view received and that |
| * needs to be recorded. |
| */ |
| void recordMovement(@NonNull MotionEvent event); |
| |
| /** |
| * Compute a prediction |
| * @return the predicted {@link android.view.MotionEvent}, or null if not possible to make a |
| * prediction. |
| */ |
| @Nullable |
| MotionEvent predict(); |
| |
| /** |
| * Notify the predictor that no more predictions are needed. Any subsequent call to |
| * {@link #predict()} will return null. |
| */ |
| void dispose(); |
| |
| /** |
| * Create a new motion predictor associated to a specific {@link android.view.View} |
| * @param view the view to associated to this predictor |
| * @return the new predictor instance |
| */ |
| static @NonNull MotionEventPredictor newInstance(@NonNull View view) { |
| return new KalmanMotionEventPredictor(); |
| } |
| } |
