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-rw-r--r--core/java/android/window/BackEvent.java16
-rw-r--r--core/java/android/window/BackProgressAnimator.java23
-rw-r--r--core/java/android/window/WindowOnBackInvokedDispatcher.java11
3 files changed, 44 insertions, 6 deletions
diff --git a/core/java/android/window/BackEvent.java b/core/java/android/window/BackEvent.java
index 4a4f561c71ed..940b133eb169 100644
--- a/core/java/android/window/BackEvent.java
+++ b/core/java/android/window/BackEvent.java
@@ -99,7 +99,21 @@ public class BackEvent implements Parcelable {
}
/**
- * Returns a value between 0 and 1 on how far along the back gesture is.
+ * Returns a value between 0 and 1 on how far along the back gesture is. This value is
+ * driven by the horizontal location of the touch point, and should be used as the fraction to
+ * seek the predictive back animation with. Specifically,
+ * <ol>
+ * <li>The progress is 0 when the touch is at the starting edge of the screen (left or right),
+ * and animation should seek to its start state.
+ * <li>The progress is approximately 1 when the touch is at the opposite side of the screen,
+ * and animation should seek to its end state. Exact end value may vary depending on
+ * screen size.
+ * </ol>
+ * <li> After the gesture finishes in cancel state, this method keeps getting invoked until the
+ * progress value animates back to 0.
+ * </ol>
+ * In-between locations are linearly interpolated based on horizontal distance from the starting
+ * edge and smooth clamped to 1 when the distance exceeds a system-wide threshold.
*/
public float getProgress() {
return mProgress;
diff --git a/core/java/android/window/BackProgressAnimator.java b/core/java/android/window/BackProgressAnimator.java
index 38c52e7473f1..b22f967e9e2a 100644
--- a/core/java/android/window/BackProgressAnimator.java
+++ b/core/java/android/window/BackProgressAnimator.java
@@ -16,8 +16,10 @@
package android.window;
+import android.annotation.NonNull;
import android.util.FloatProperty;
+import com.android.internal.dynamicanimation.animation.DynamicAnimation;
import com.android.internal.dynamicanimation.animation.SpringAnimation;
import com.android.internal.dynamicanimation.animation.SpringForce;
@@ -123,6 +125,27 @@ public class BackProgressAnimator {
mProgress = 0;
}
+ /**
+ * Animate the back progress animation from current progress to start position.
+ * This should be called when back is cancelled.
+ *
+ * @param finishCallback the callback to be invoked when the progress is reach to 0.
+ */
+ public void onBackCancelled(@NonNull Runnable finishCallback) {
+ final DynamicAnimation.OnAnimationEndListener listener =
+ new DynamicAnimation.OnAnimationEndListener() {
+ @Override
+ public void onAnimationEnd(DynamicAnimation animation, boolean canceled, float value,
+ float velocity) {
+ mSpring.removeEndListener(this);
+ finishCallback.run();
+ reset();
+ }
+ };
+ mSpring.addEndListener(listener);
+ mSpring.animateToFinalPosition(0);
+ }
+
private void updateProgressValue(float progress) {
if (mLastBackEvent == null || mCallback == null || !mStarted) {
return;
diff --git a/core/java/android/window/WindowOnBackInvokedDispatcher.java b/core/java/android/window/WindowOnBackInvokedDispatcher.java
index dd9483a9c759..bfa3447076d5 100644
--- a/core/java/android/window/WindowOnBackInvokedDispatcher.java
+++ b/core/java/android/window/WindowOnBackInvokedDispatcher.java
@@ -255,11 +255,12 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
@Override
public void onBackCancelled() {
Handler.getMain().post(() -> {
- mProgressAnimator.reset();
- final OnBackAnimationCallback callback = getBackAnimationCallback();
- if (callback != null) {
- callback.onBackCancelled();
- }
+ mProgressAnimator.onBackCancelled(() -> {
+ final OnBackAnimationCallback callback = getBackAnimationCallback();
+ if (callback != null) {
+ callback.onBackCancelled();
+ }
+ });
});
}