WebView: improved nested scroll

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -590,10 +590,8 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                     } else
                         return false;
                 } else {
-                    //view.getParent().requestDisallowInterceptTouchEvent(false);
+                    if (view.getId() == R.id.tvBody)
-                    //return (view.getId() == R.id.wvBody && ev.getAction() == MotionEvent.ACTION_MOVE);
+                        view.getParent().requestDisallowInterceptTouchEvent(false);
-                    boolean intercept = (view.getId() == R.id.wvBody && ((WebViewEx) wvBody).isZoomedY());
-                    view.getParent().requestDisallowInterceptTouchEvent(intercept);
                     return false;
                 }
             }
@@ -2779,21 +2777,6 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                                     properties.setPosition(message.id, new Pair<Integer, Integer>(scrollX, scrollY));
                                 }
 
-                                @Override
-                                public void onOverScrolled(int scrollX, int scrollY, int dx, int dy, boolean clampedX, boolean clampedY) {
-                                    if (clampedY && ((WebViewEx) wvBody).isZoomedY()) {
-                                        boolean flinged = false;
-                                        try {
-                                            if (!webview_legacy && rv != null)
-                                                flinged = rv.fling(dx * 10, dy * 10);
-                                        } catch (Throwable ex) {
-                                            Log.e(ex);
-                                        }
-                                        if (!flinged)
-                                            properties.scrollBy(dx, dy);
-                                    }
-                                }
-
                                 @Override
                                 public boolean onOpenLink(String url) {
                                     if (parentFragment == null)

app/src/main/java/eu/faircode/email/WebViewEx.java

@@ -271,71 +271,6 @@ public class WebViewEx extends WebView implements DownloadListener, View.OnLongC
         this.intf.onSizeChanged(w, h, ow, oh);
     }
 
-    @Override
-    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {
-        final int overScrollMode = getOverScrollMode();
-        final boolean canScrollHorizontal =
-                computeHorizontalScrollRange() > computeHorizontalScrollExtent();
-        final boolean canScrollVertical =
-                computeVerticalScrollRange() > computeVerticalScrollExtent();
-        final boolean overScrollHorizontal = overScrollMode == OVER_SCROLL_ALWAYS ||
-                (overScrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollHorizontal);
-        final boolean overScrollVertical = overScrollMode == OVER_SCROLL_ALWAYS ||
-                (overScrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollVertical);
-
-        int newScrollX = scrollX + deltaX;
-        if (!overScrollHorizontal) {
-            maxOverScrollX = 0;
-        }
-
-        int newScrollY = scrollY + deltaY;
-        if (!overScrollVertical) {
-            maxOverScrollY = 0;
-        }
-
-        // Clamp values if at the limits and record
-        final int left = -maxOverScrollX;
-        final int right = maxOverScrollX + scrollRangeX;
-        final int top = -maxOverScrollY;
-        final int bottom = maxOverScrollY + scrollRangeY;
-
-        boolean clampedX = false;
-        if (newScrollX > right) {
-            newScrollX = right;
-            clampedX = true;
-        } else if (newScrollX < left) {
-            newScrollX = left;
-            clampedX = true;
-        }
-
-        boolean clampedY = false;
-        if (newScrollY > bottom) {
-            newScrollY = bottom;
-            clampedY = true;
-        } else if (newScrollY < top) {
-            newScrollY = top;
-            clampedY = true;
-        }
-
-        Log.i("onOverScrolled" +
-                " clampedY=" + clampedY +
-                " scrollY=" + scrollY +
-                " deltaY=" + deltaY +
-                " RangeY=" + scrollRangeY +
-                " maxY=" + maxOverScrollY +
-                " newY=" + (scrollY + deltaY) + "/" + newScrollY +
-                " dy=" + deltaY +
-                " top=" + top +
-                " bottom=" + bottom);
-
-        if (Math.abs(deltaY) > bottom - top)
-            deltaY = (deltaY > 0 ? 1 : -1) * (bottom - top);
-
-        intf.onOverScrolled(scrollX, scrollY, deltaX, deltaY, clampedX, clampedY);
-
-        return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);
-    }
-
     @Override
     public void onDownloadStart(
             String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
@@ -374,19 +309,28 @@ public class WebViewEx extends WebView implements DownloadListener, View.OnLongC
         return super.onGenericMotionEvent(event);
     }
 
-    public boolean isZoomedY() {
+    private float lastY;
-/*
-        DisplayMetrics dm = getResources().getDisplayMetrics();
-        int ch = Math.round(getContentHeight() * dm.density);
-        int dp6 = Math.round(6 * dm.density);
-        return (ch - dp6 > getHeight());
-*/
-        int ytend = computeVerticalScrollExtent();
-        if (ytend == 0)
-            return false;
 
-        float yscale = computeVerticalScrollRange() / (float) ytend;
+    @Override
-        return (yscale > 1.01);
+    public boolean onTouchEvent(MotionEvent event) {
+        boolean intercept = false;
+        if (event.getAction() == MotionEvent.ACTION_DOWN)
+            intercept = true; // Prevent ACTION_CANCEL on fling
+        else if (event.getAction() == MotionEvent.ACTION_MOVE) {
+            int range = computeVerticalScrollRange();
+            int extend = computeVerticalScrollExtent();
+            boolean canScrollVertical = (range > extend);
+            if (canScrollVertical) {
+                int bottom = range - extend;
+                int off = computeVerticalScrollOffset();
+                float dy = lastY - event.getY();
+                intercept = (off > 0 || dy >= 0) && (off < bottom || dy <= 0);
+            }
+        }
+        getParent().requestDisallowInterceptTouchEvent(intercept);
+
+        lastY = event.getY();
+        return super.onTouchEvent(event);
     }
 
     public static boolean isFeatureSupported(Context context, String feature) {
@@ -464,8 +408,6 @@ public class WebViewEx extends WebView implements DownloadListener, View.OnLongC
 
         void onScrollChange(int scrollX, int scrollY);
 
-        void onOverScrolled(int scrollX, int scrollY, int dx, int dy, boolean clampedX, boolean clampedY);
-
         boolean onOpenLink(String url);
     }
 }