RecyclerView scroll fixes

* Move all focus-related work arouns to NewPipeRecyclerView
* Try to pass focus within closer parents first
* Do small arrow scroll if there are not more focusables in move direction
This commit is contained in:
Alexander-- 2019-11-08 14:26:12 +07:00
parent 6e76610f30
commit a7c31e6bcc

View file

@ -18,55 +18,202 @@
package org.schabi.newpipe.views;
import android.content.Context;
import android.graphics.Rect;
import android.os.Build;
import android.util.AttributeSet;
import android.util.Log;
import android.view.FocusFinder;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.recyclerview.widget.RecyclerView;
public class NewPipeRecyclerView extends RecyclerView {
private static final String TAG = "FixedRecyclerView";
private static final String TAG = "NewPipeRecyclerView";
private Rect focusRect = new Rect();
private Rect tempFocus = new Rect();
private boolean allowDpadScroll;
public NewPipeRecyclerView(@NonNull Context context) {
super(context);
init();
}
public NewPipeRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public NewPipeRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
@Override
public View focusSearch(int direction) {
return null;
private void init() {
setFocusable(true);
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
}
public void setFocusScrollAllowed(boolean allowDpadScroll) {
this.allowDpadScroll = allowDpadScroll;
}
@Override
public View focusSearch(View focused, int direction) {
// RecyclerView has buggy focusSearch(), that calls into Adapter several times,
// but ultimately fails to produce correct results in many cases. To add insult to injury,
// it's focusSearch() hard-codes several behaviors, incompatible with widely accepted focus
// handling practices: RecyclerView does not allow Adapter to give focus to itself (!!) and
// always checks, that returned View is located in "correct" direction (which prevents us
// from temporarily giving focus to special hidden View).
return null;
}
@Override
protected void removeDetachedView(View child, boolean animate) {
if (child.hasFocus()) {
// If the focused child is being removed (can happen during very fast scrolling),
// temporarily give focus to ourselves. This will usually result in another child
// gaining focus (which one does not really matter, because at that point scrolling
// is FAST, and that child will soon be off-screen too)
requestFocus();
}
super.removeDetachedView(child, animate);
}
// we override focusSearch to always return null, so all moves moves lead to dispatchUnhandledMove()
// as added advantage, we can fully swallow some kinds of moves (such as downward movement, that
// happens when loading additional contents is in progress
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
View found = super.focusSearch(focused, direction);
if (found != null) {
found.requestFocus(direction);
tempFocus.setEmpty();
// save focus rect before further manipulation (both focusSearch() and scrollBy()
// can mess with focused View by moving it off-screen and detaching)
if (focused != null) {
View focusedItem = findContainingItemView(focused);
if (focusedItem != null) {
focusedItem.getHitRect(focusRect);
}
}
// call focusSearch() to initiate layout, but disregard returned View for now
View adapterResult = super.focusSearch(focused, direction);
if (adapterResult != null && !isOutside(adapterResult)) {
adapterResult.requestFocus(direction);
return true;
}
if (direction == View.FOCUS_UP) {
if (canScrollVertically(-1)) {
scrollBy(0, -10);
if (arrowScroll(direction)) {
// if RecyclerView can not yield focus, but there is still some scrolling space in indicated,
// direction, scroll some fixed amount in that direction (the same logic in ScrollView)
return true;
}
if (focused != this && direction == FOCUS_DOWN && !allowDpadScroll) {
Log.i(TAG, "Consuming downward scroll: content load in progress");
return true;
}
if (tryFocusFinder(direction)) {
return true;
}
if (adapterResult != null) {
adapterResult.requestFocus(direction);
return true;
}
return super.dispatchUnhandledMove(focused, direction);
}
private boolean tryFocusFinder(int direction) {
if (Build.VERSION.SDK_INT >= 28) {
// Android 9 implemented bunch of handy changes to focus, that render code below less useful, and
// also broke findNextFocusFromRect in way, that render this hack useless
return false;
}
FocusFinder finder = FocusFinder.getInstance();
// try to use FocusFinder instead of adapter
ViewGroup root = (ViewGroup) getRootView();
tempFocus.set(focusRect);
root.offsetDescendantRectToMyCoords(this, tempFocus);
View focusFinderResult = finder.findNextFocusFromRect(root, tempFocus, direction);
if (focusFinderResult != null && !isOutside(focusFinderResult)) {
focusFinderResult.requestFocus(direction);
return true;
}
// look for focus in our ancestors, increasing search scope with each failure
// this provides much better locality than using FocusFinder with root
ViewGroup parent = (ViewGroup) getParent();
while (parent != root) {
tempFocus.set(focusRect);
parent.offsetDescendantRectToMyCoords(this, tempFocus);
View candidate = finder.findNextFocusFromRect(parent, tempFocus, direction);
if (candidate != null && candidate.requestFocus(direction)) {
return true;
}
parent = (ViewGroup) parent.getParent();
}
return false;
}
return super.dispatchUnhandledMove(focused, direction);
private boolean arrowScroll(int direction) {
switch (direction) {
case FOCUS_DOWN:
if (!canScrollVertically(1)) {
return false;
}
scrollBy(0, 100);
break;
case FOCUS_UP:
if (!canScrollVertically(-1)) {
return false;
}
scrollBy(0, -100);
break;
case FOCUS_LEFT:
if (!canScrollHorizontally(-1)) {
return false;
}
scrollBy(-100, 0);
break;
case FOCUS_RIGHT:
if (!canScrollHorizontally(-1)) {
return false;
}
scrollBy(100, 0);
break;
default:
return false;
}
return true;
}
private boolean isOutside(View view) {
return findContainingItemView(view) == null;
}
}