/*  * HorizontalListView.java v1.5  *  *  * The MIT License  * Copyright (c) 2011 Paul Soucy ([email protected])  *  * Permission is hereby granted, free of charge, to any person obtaining a copy  * of this software and associated documentation files (the "Software"), to deal  * in the Software without restriction, including without limitation the rights  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell  * copies of the Software, and to permit persons to whom the Software is  * furnished to do so, subject to the following conditions:  *  * The above copyright notice and this permission notice shall be included in  * all copies or substantial portions of the Software.  *  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN  * THE SOFTWARE.  *  */import java.util.LinkedList;import java.util.Queue;import android.content.Context;import android.database.DataSetObserver;import android.graphics.Rect;import android.util.AttributeSet;import android.view.GestureDetector;import android.view.GestureDetector.OnGestureListener;import android.view.MotionEvent;import android.view.View;import android.widget.AdapterView;import android.widget.ListAdapter;import android.widget.Scroller;public class HorizontalListView extends AdapterView<ListAdapter> { public boolean mAlwaysOverrideTouch = true; protected ListAdapter mAdapter; private int mLeftViewIndex = -1; private int mRightViewIndex = 0; protected int mCurrentX; protected int mNextX; private int mMaxX = Integer.MAX_VALUE; private int mDisplayOffset = 0; protected Scroller mScroller; private GestureDetector mGesture; private Queue<View> mRemovedViewQueue = new LinkedList<View>(); private OnItemSelectedListener mOnItemSelected; private OnItemClickListener mOnItemClicked; private OnItemLongClickListener mOnItemLongClicked; private boolean mDataChanged = false; public HorizontalListView(Context context, AttributeSet attrs) {  super(context, attrs);  initView(); } private synchronized void initView() {  mLeftViewIndex = -1;  mRightViewIndex = 0;  mDisplayOffset = 0;  mCurrentX = 0;  mNextX = 0;  mMaxX = Integer.MAX_VALUE;  mScroller = new Scroller(getContext());  mGesture = new GestureDetector(getContext(), mOnGesture); } @Override public void setOnItemSelectedListener(AdapterView.OnItemSelectedListener listener) {  mOnItemSelected = listener; } @Override public void setOnItemClickListener(AdapterView.OnItemClickListener listener){  mOnItemClicked = listener; } @Override public void setOnItemLongClickListener(AdapterView.OnItemLongClickListener listener) {  mOnItemLongClicked = listener; } private DataSetObserver mDataObserver = new DataSetObserver() {  @Override  public void onChanged() {   synchronized(HorizontalListView.this){    mDataChanged = true;   }   invalidate();   requestLayout();  }  @Override  public void onInvalidated() {   reset();   invalidate();   requestLayout();  } }; @Override public ListAdapter getAdapter() {  return mAdapter; } @Override public View getSelectedView() {  //TODO: implement  return null; } @Override public void setAdapter(ListAdapter adapter) {  if(mAdapter != null) {   mAdapter.unregisterDataSetObserver(mDataObserver);  }  mAdapter = adapter;  mAdapter.registerDataSetObserver(mDataObserver);  reset(); } private synchronized void reset(){  initView();  removeAllViewsInLayout();  requestLayout(); } @Override public void setSelection(int position) {  //TODO: implement } private void addAndMeasureChild(final View child, int viewPos) {  LayoutParams params = child.getLayoutParams();  if(params == null) {   params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);  }  addViewInLayout(child, viewPos, params, true);  child.measure(MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.AT_MOST),    MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.AT_MOST)); } @Override protected synchronized void onLayout(boolean changed, int left, int top, int right, int bottom) {  super.onLayout(changed, left, top, right, bottom);  if(mAdapter == null){   return;  }  if(mDataChanged){   int oldCurrentX = mCurrentX;   initView();   removeAllViewsInLayout();   mNextX = oldCurrentX;   mDataChanged = false;  }  if(mScroller.computeScrollOffset()){   int scrollx = mScroller.getCurrX();   mNextX = scrollx;  }  if(mNextX <= 0){   mNextX = 0;   mScroller.forceFinished(true);  }  if(mNextX >= mMaxX) {   mNextX = mMaxX;   mScroller.forceFinished(true);  }  int dx = mCurrentX - mNextX;  removeNonVisibleItems(dx);  fillList(dx);  positionItems(dx);  mCurrentX = mNextX;  if(!mScroller.isFinished()){   post(new Runnable(){    @Override    public void run() {     requestLayout();    }   });  } } private void fillList(final int dx) {  int edge = 0;  View child = getChildAt(getChildCount()-1);  if(child != null) {   edge = child.getRight();  }  fillListRight(edge, dx);  edge = 0;  child = getChildAt(0);  if(child != null) {   edge = child.getLeft();  }  fillListLeft(edge, dx); } private void fillListRight(int rightEdge, final int dx) {  while(rightEdge + dx < getWidth() && mRightViewIndex < mAdapter.getCount()) {   View child = mAdapter.getView(mRightViewIndex, mRemovedViewQueue.poll(), this);   addAndMeasureChild(child, -1);   rightEdge += child.getMeasuredWidth();   if(mRightViewIndex == mAdapter.getCount()-1) {    mMaxX = mCurrentX + rightEdge - getWidth();   }   if (mMaxX < 0) {    mMaxX = 0;   }   mRightViewIndex++;  } } private void fillListLeft(int leftEdge, final int dx) {  while(leftEdge + dx > 0 && mLeftViewIndex >= 0) {   View child = mAdapter.getView(mLeftViewIndex, mRemovedViewQueue.poll(), this);   addAndMeasureChild(child, 0);   leftEdge -= child.getMeasuredWidth();   mLeftViewIndex--;   mDisplayOffset -= child.getMeasuredWidth();  } } private void removeNonVisibleItems(final int dx) {  View child = getChildAt(0);  while(child != null && child.getRight() + dx <= 0) {   mDisplayOffset += child.getMeasuredWidth();   mRemovedViewQueue.offer(child);   removeViewInLayout(child);   mLeftViewIndex++;   child = getChildAt(0);  }  child = getChildAt(getChildCount()-1);  while(child != null && child.getLeft() + dx >= getWidth()) {   mRemovedViewQueue.offer(child);   removeViewInLayout(child);   mRightViewIndex--;   child = getChildAt(getChildCount()-1);  } } private void positionItems(final int dx) {  if(getChildCount() > 0){   mDisplayOffset += dx;   int left = mDisplayOffset;   for(int i=0;i<getChildCount();i++){    View child = getChildAt(i);    int childWidth = child.getMeasuredWidth();    child.layout(left, 0, left + childWidth, child.getMeasuredHeight());    left += childWidth + child.getPaddingRight();   }  } } public synchronized void scrollTo(int x) {  mScroller.startScroll(mNextX, 0, x - mNextX, 0);  requestLayout(); } @Override public boolean dispatchTouchEvent(MotionEvent ev) {  boolean handled = super.dispatchTouchEvent(ev);  handled |= mGesture.onTouchEvent(ev);  return handled; } protected boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,        float velocityY) {  synchronized(HorizontalListView.this){   mScroller.fling(mNextX, 0, (int)-velocityX, 0, 0, mMaxX, 0, 0);  }  requestLayout();  return true; } protected boolean onDown(MotionEvent e) {  mScroller.forceFinished(true);  return true; } private OnGestureListener mOnGesture = new GestureDetector.SimpleOnGestureListener() {  @Override  public boolean onDown(MotionEvent e) {   return HorizontalListView.this.onDown(e);  }  @Override  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,        float velocityY) {   return HorizontalListView.this.onFling(e1, e2, velocityX, velocityY);  }  @Override  public boolean onScroll(MotionEvent e1, MotionEvent e2,        float distanceX, float distanceY) {   synchronized(HorizontalListView.this){    mNextX += (int)distanceX;   }   requestLayout();   return true;  }  @Override  public boolean onSingleTapConfirmed(MotionEvent e) {   for(int i=0;i<getChildCount();i++){    View child = getChildAt(i);    if (isEventWithinView(e, child)) {     if(mOnItemClicked != null){      mOnItemClicked.onItemClick(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId( mLeftViewIndex + 1 + i ));     }     if(mOnItemSelected != null){      mOnItemSelected.onItemSelected(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId( mLeftViewIndex + 1 + i ));     }     break;    }   }   return true;  }  @Override  public void onLongPress(MotionEvent e) {   int childCount = getChildCount();   for (int i = 0; i < childCount; i++) {    View child = getChildAt(i);    if (isEventWithinView(e, child)) {     if (mOnItemLongClicked != null) {      mOnItemLongClicked.onItemLongClick(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));     }     break;    }   }  }  private boolean isEventWithinView(MotionEvent e, View child) {   Rect viewRect = new Rect();   int[] childPosition = new int[2];   child.getLocationOnScreen(childPosition);   int left = childPosition[0];   int right = left + child.getWidth();   int top = childPosition[1];   int bottom = top + child.getHeight();   viewRect.set(left, top, right, bottom);   return viewRect.contains((int) e.getRawX(), (int) e.getRawY());  } };}