Enables scroll capture for WebView
Bug: 190731582
Test: manual, long screenshot Gmail message
Change-Id: I16cd568ab155d308e444c448cc77e538c6415061
diff --git a/core/java/com/android/internal/view/ScrollCaptureInternal.java b/core/java/com/android/internal/view/ScrollCaptureInternal.java
index e3a9fda..72b5488 100644
--- a/core/java/com/android/internal/view/ScrollCaptureInternal.java
+++ b/core/java/com/android/internal/view/ScrollCaptureInternal.java
@@ -25,6 +25,7 @@
import android.view.ScrollCaptureCallback;
import android.view.View;
import android.view.ViewGroup;
+import android.webkit.WebView;
import android.widget.ListView;
/**
@@ -43,7 +44,7 @@
private static final int DOWN = 1;
/**
- * Not a ViewGroup, or cannot scroll according to View APIs.
+ * Cannot scroll according to {@link View#canScrollVertically}.
*/
public static final int TYPE_FIXED = 0;
@@ -60,7 +61,7 @@
public static final int TYPE_RECYCLING = 2;
/**
- * The ViewGroup scrolls, but has no child views in
+ * Unknown scrollable view with no child views (or not a subclass of ViewGroup).
*/
private static final int TYPE_OPAQUE = 3;
@@ -73,16 +74,6 @@
* as excluded during scroll capture search.
*/
private static int detectScrollingType(View view) {
- // Must be a ViewGroup
- if (!(view instanceof ViewGroup)) {
- if (DEBUG_VERBOSE) {
- Log.v(TAG, "hint: not a subclass of ViewGroup");
- }
- return TYPE_FIXED;
- }
- if (DEBUG_VERBOSE) {
- Log.v(TAG, "hint: is a subclass of ViewGroup");
- }
// Confirm that it can scroll.
if (!(view.canScrollVertically(DOWN) || view.canScrollVertically(UP))) {
// Nothing to scroll here, move along.
@@ -94,6 +85,17 @@
if (DEBUG_VERBOSE) {
Log.v(TAG, "hint: can be scrolled up or down");
}
+ // Must be a ViewGroup
+ if (!(view instanceof ViewGroup)) {
+ if (DEBUG_VERBOSE) {
+ Log.v(TAG, "hint: not a subclass of ViewGroup");
+ }
+ return TYPE_OPAQUE;
+ }
+ if (DEBUG_VERBOSE) {
+ Log.v(TAG, "hint: is a subclass of ViewGroup");
+ }
+
// ScrollViews accept only a single child.
if (((ViewGroup) view).getChildCount() > 1) {
if (DEBUG_VERBOSE) {
@@ -188,6 +190,18 @@
}
return new ScrollCaptureViewSupport<>((ViewGroup) view,
new RecyclerViewCaptureHelper());
+ case TYPE_OPAQUE:
+ if (DEBUG) {
+ Log.d(TAG, "scroll capture: FOUND " + view.getClass().getName()
+ + "[" + resolveId(view.getContext(), view.getId()) + "]"
+ + " -> TYPE_OPAQUE");
+ }
+ if (view instanceof WebView) {
+ Log.d(TAG, "scroll capture: Using WebView support");
+ return new ScrollCaptureViewSupport<>((WebView) view,
+ new WebViewCaptureHelper());
+ }
+ break;
case TYPE_FIXED:
// ignore
break;
diff --git a/core/java/com/android/internal/view/WebViewCaptureHelper.java b/core/java/com/android/internal/view/WebViewCaptureHelper.java
new file mode 100644
index 0000000..e6a311c
--- /dev/null
+++ b/core/java/com/android/internal/view/WebViewCaptureHelper.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2021 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 com.android.internal.view;
+
+import static android.util.MathUtils.constrain;
+
+import static java.lang.Math.max;
+import static java.lang.Math.min;
+
+import android.annotation.NonNull;
+import android.graphics.Rect;
+import android.webkit.WebView;
+
+/**
+ * ScrollCapture for WebView.
+ */
+class WebViewCaptureHelper implements ScrollCaptureViewHelper<WebView> {
+ private static final String TAG = "WebViewScrollCapture";
+
+ private final Rect mRequestWebViewLocal = new Rect();
+ private final Rect mWebViewBounds = new Rect();
+
+ private int mOriginScrollY;
+ private int mOriginScrollX;
+
+ @Override
+ public boolean onAcceptSession(@NonNull WebView view) {
+ return view.isVisibleToUser()
+ && (view.getContentHeight() * view.getScale()) > view.getHeight();
+ }
+
+ @Override
+ public void onPrepareForStart(@NonNull WebView view, @NonNull Rect scrollBounds) {
+ mOriginScrollX = view.getScrollX();
+ mOriginScrollY = view.getScrollY();
+ }
+
+ @NonNull
+ @Override
+ public ScrollResult onScrollRequested(@NonNull WebView view, @NonNull Rect scrollBounds,
+ @NonNull Rect requestRect) {
+
+ int scrollDelta = view.getScrollY() - mOriginScrollY;
+
+ ScrollResult result = new ScrollResult();
+ result.requestedArea = new Rect(requestRect);
+ result.availableArea = new Rect();
+ result.scrollDelta = scrollDelta;
+
+ mWebViewBounds.set(0, 0, view.getWidth(), view.getHeight());
+
+ if (!view.isVisibleToUser()) {
+ return result;
+ }
+
+ // Map the request into local coordinates
+ mRequestWebViewLocal.set(requestRect);
+ mRequestWebViewLocal.offset(0, -scrollDelta);
+
+ // Offset to center the rect vertically, clamp to available content
+ int upLimit = min(0, -view.getScrollY());
+ int contentHeightPx = (int) (view.getContentHeight() * view.getScale());
+ int downLimit = max(0, (contentHeightPx - view.getHeight()) - view.getScrollY());
+ int scrollToCenter = mRequestWebViewLocal.centerY() - mWebViewBounds.centerY();
+ int scrollMovement = constrain(scrollToCenter, upLimit, downLimit);
+
+ // Scroll and update relative based on the new position
+ view.scrollBy(mOriginScrollX, scrollMovement);
+ scrollDelta = view.getScrollY() - mOriginScrollY;
+ mRequestWebViewLocal.offset(0, -scrollMovement);
+ result.scrollDelta = scrollDelta;
+
+ if (mRequestWebViewLocal.intersect(mWebViewBounds)) {
+ result.availableArea = new Rect(mRequestWebViewLocal);
+ result.availableArea.offset(0, result.scrollDelta);
+ }
+ return result;
+ }
+
+ @Override
+ public void onPrepareForEnd(@NonNull WebView view) {
+ view.scrollTo(mOriginScrollX, mOriginScrollY);
+ }
+
+}
+
