2015-05-03 13:48:36 +02:00
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/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific languag`e governing permissions and
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* limitations under the License.
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*/
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2015-09-24 22:52:02 +02:00
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package org.telegram.messenger.support.widget;
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2015-05-03 13:48:36 +02:00
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import android.view.View;
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/**
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* Helper class that keeps temporary state while {LayoutManager} is filling out the empty
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* space.
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*/
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class LayoutState {
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final static String TAG = "LayoutState";
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final static int LAYOUT_START = -1;
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final static int LAYOUT_END = 1;
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final static int INVALID_LAYOUT = Integer.MIN_VALUE;
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final static int ITEM_DIRECTION_HEAD = -1;
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final static int ITEM_DIRECTION_TAIL = 1;
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final static int SCOLLING_OFFSET_NaN = Integer.MIN_VALUE;
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/**
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* Number of pixels that we should fill, in the layout direction.
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*/
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int mAvailable;
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/**
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* Current position on the adapter to get the next item.
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*/
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int mCurrentPosition;
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/**
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* Defines the direction in which the data adapter is traversed.
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* Should be {@link #ITEM_DIRECTION_HEAD} or {@link #ITEM_DIRECTION_TAIL}
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*/
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int mItemDirection;
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/**
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* Defines the direction in which the layout is filled.
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* Should be {@link #LAYOUT_START} or {@link #LAYOUT_END}
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*/
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int mLayoutDirection;
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/**
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2015-07-22 20:56:37 +02:00
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* This is the target pixel closest to the start of the layout that we are trying to fill
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2015-05-03 13:48:36 +02:00
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*/
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2015-07-22 20:56:37 +02:00
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int mStartLine = 0;
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/**
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* This is the target pixel closest to the end of the layout that we are trying to fill
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*/
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int mEndLine = 0;
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2015-05-03 13:48:36 +02:00
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/**
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* @return true if there are more items in the data adapter
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*/
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boolean hasMore(RecyclerView.State state) {
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return mCurrentPosition >= 0 && mCurrentPosition < state.getItemCount();
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}
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/**
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* Gets the view for the next element that we should render.
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* Also updates current item index to the next item, based on {@link #mItemDirection}
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*
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* @return The next element that we should render.
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*/
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View next(RecyclerView.Recycler recycler) {
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final View view = recycler.getViewForPosition(mCurrentPosition);
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mCurrentPosition += mItemDirection;
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return view;
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}
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2015-07-22 20:56:37 +02:00
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@Override
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public String toString() {
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return "LayoutState{" +
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"mAvailable=" + mAvailable +
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", mCurrentPosition=" + mCurrentPosition +
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", mItemDirection=" + mItemDirection +
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", mLayoutDirection=" + mLayoutDirection +
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", mStartLine=" + mStartLine +
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", mEndLine=" + mEndLine +
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'}';
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}
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2015-05-03 13:48:36 +02:00
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}
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