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/*
* 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.widget;
import android.content.Context;
import android.graphics.Color;
import android.support.v7.widget.LinearLayoutManager;
import android.util.AttributeSet;
import android.view.View;
import com.android.launcher3.BaseRecyclerView;
/**
* The widgets recycler view.
*/
public class WidgetsRecyclerView extends BaseRecyclerView {
private static final String TAG = "WidgetsRecyclerView";
private WidgetsListAdapter mAdapter;
public WidgetsRecyclerView(Context context) {
this(context, null);
}
public WidgetsRecyclerView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public WidgetsRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
// API 21 and below only support 3 parameter ctor.
super(context, attrs, defStyleAttr);
}
public WidgetsRecyclerView(Context context, AttributeSet attrs, int defStyleAttr,
int defStyleRes) {
this(context, attrs, defStyleAttr);
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
addOnItemTouchListener(this);
// create a layout manager with Launcher's context so that scroll position
// can be preserved during screen rotation.
setLayoutManager(new LinearLayoutManager(getContext()));
}
@Override
public void setAdapter(Adapter adapter) {
super.setAdapter(adapter);
mAdapter = (WidgetsListAdapter) adapter;
}
/**
* Maps the touch (from 0..1) to the adapter position that should be visible.
*/
@Override
public String scrollToPositionAtProgress(float touchFraction) {
// Skip early if widgets are not bound.
if (isModelNotReady()) {
return "";
}
// Stop the scroller if it is scrolling
stopScroll();
int rowCount = mAdapter.getItemCount();
float pos = rowCount * touchFraction;
int availableScrollHeight = getAvailableScrollHeight();
LinearLayoutManager layoutManager = ((LinearLayoutManager) getLayoutManager());
layoutManager.scrollToPositionWithOffset(0, (int) -(availableScrollHeight * touchFraction));
int posInt = (int) ((touchFraction == 1)? pos -1 : pos);
return mAdapter.getSectionName(posInt);
}
/**
* Updates the bounds for the scrollbar.
*/
@Override
public void onUpdateScrollbar(int dy) {
// Skip early if widgets are not bound.
if (isModelNotReady()) {
return;
}
// Skip early if, there no child laid out in the container.
int scrollY = getCurrentScrollY();
if (scrollY < 0) {
mScrollbar.setThumbOffsetY(-1);
return;
}
synchronizeScrollBarThumbOffsetToViewScroll(scrollY, getAvailableScrollHeight());
}
@Override
public int getCurrentScrollY() {
// Skip early if widgets are not bound.
if (isModelNotReady() || getChildCount() == 0) {
return -1;
}
View child = getChildAt(0);
int rowIndex = getChildPosition(child);
int y = (child.getMeasuredHeight() * rowIndex);
int offset = getLayoutManager().getDecoratedTop(child);
return getPaddingTop() + y - offset;
}
/**
* Returns the available scroll height:
* AvailableScrollHeight = Total height of the all items - last page height
*/
@Override
protected int getAvailableScrollHeight() {
View child = getChildAt(0);
int height = child.getMeasuredHeight() * mAdapter.getItemCount();
int totalHeight = getPaddingTop() + height + getPaddingBottom();
int availableScrollHeight = totalHeight - getScrollbarTrackHeight();
return availableScrollHeight;
}
private boolean isModelNotReady() {
return mAdapter.getItemCount() == 0;
}
}
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