Make common base class to update container bounds and to handle scroll logic.
Bug: 20763871
Change-Id: I8c2f45cfb10964e4be7e9c07c89dd336585c9989
diff --git a/src/com/android/launcher3/BaseContainerRecyclerView.java b/src/com/android/launcher3/BaseContainerRecyclerView.java
new file mode 100644
index 0000000..5b30e3d
--- /dev/null
+++ b/src/com/android/launcher3/BaseContainerRecyclerView.java
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2015 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.launcher3;
+
+import android.content.Context;
+import android.support.v7.widget.RecyclerView;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import com.android.launcher3.util.Thunk;
+
+/**
+ * A base {@link RecyclerView}, which will NOT intercept a touch sequence unless the scrolling
+ * velocity is below a predefined threshold.
+ */
+public class BaseContainerRecyclerView extends RecyclerView
+ implements RecyclerView.OnItemTouchListener {
+
+ private static final int SCROLL_DELTA_THRESHOLD_DP = 4;
+
+ /** Keeps the last known scrolling delta/velocity along y-axis. */
+ @Thunk int mDy = 0;
+ private float mDeltaThreshold;
+ private RecyclerView.OnScrollListener mScrollListenerProxy;
+
+ public BaseContainerRecyclerView(Context context) {
+ this(context, null);
+ }
+
+ public BaseContainerRecyclerView(Context context, AttributeSet attrs) {
+ this(context, attrs, 0);
+ }
+
+ public BaseContainerRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
+ super(context, attrs, defStyleAttr);
+ mDeltaThreshold = getResources().getDisplayMetrics().density * SCROLL_DELTA_THRESHOLD_DP;
+
+ ScrollListener listener = new ScrollListener();
+ setOnScrollListener(listener);
+ }
+
+ private class ScrollListener extends OnScrollListener {
+ public ScrollListener() {
+ // Do nothing
+ }
+
+ @Override
+ public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+ mDy = dy;
+ if (mScrollListenerProxy != null) {
+ mScrollListenerProxy.onScrolled(recyclerView, dx, dy);
+ }
+ }
+ }
+
+ /**
+ * Sets an additional scroll listener, only needed for LMR1 version of the support lib.
+ */
+ public void setOnScrollListenerProxy(RecyclerView.OnScrollListener listener) {
+ mScrollListenerProxy = listener;
+ }
+
+ @Override
+ protected void onFinishInflate() {
+ super.onFinishInflate();
+ addOnItemTouchListener(this);
+ }
+
+ @Override
+ public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent ev) {
+ if (shouldStopScroll(ev)) {
+ stopScroll();
+ }
+ return false;
+ }
+
+ @Override
+ public void onTouchEvent(RecyclerView rv, MotionEvent ev) {
+ // Do nothing.
+ }
+
+ public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+ // DO NOT REMOVE, NEEDED IMPLEMENTATION FOR M BUILDS
+ }
+
+ /**
+ * Returns whether this {@link MotionEvent} should trigger the scroll to be stopped.
+ */
+ protected boolean shouldStopScroll(MotionEvent ev) {
+ if (ev.getAction() == MotionEvent.ACTION_DOWN) {
+ if ((Math.abs(mDy) < mDeltaThreshold &&
+ getScrollState() != RecyclerView.SCROLL_STATE_IDLE)) {
+ // now the touch events are being passed to the {@link WidgetCell} until the
+ // touch sequence goes over the touch slop.
+ return true;
+ }
+ }
+ return false;
+ }
+}
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