横向listview源码.
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);}@Overridepublic void setOnItemSelectedListener(AdapterView.OnItemSelectedListener listener) {mOnItemSelected = listener;}@Overridepublic void setOnItemClickListener(AdapterView.OnItemClickListener listener){mOnItemClicked = listener;}@Overridepublic void setOnItemLongClickListener(AdapterView.OnItemLongClickListener listener) {mOnItemLongClicked = listener;}private DataSetObserver mDataObserver = new DataSetObserver() {@Overridepublic void onChanged() {synchronized(HorizontalListView.this){mDataChanged = true;}invalidate();requestLayout();}@Overridepublic void onInvalidated() {reset();invalidate();requestLayout();}};@Overridepublic ListAdapter getAdapter() {return mAdapter;}@Overridepublic View getSelectedView() {//TODO: implementreturn null;}@Overridepublic void setAdapter(ListAdapter adapter) {if(mAdapter != null) {mAdapter.unregisterDataSetObserver(mDataObserver);}mAdapter = adapter;mAdapter.registerDataSetObserver(mDataObserver);reset();}private synchronized void reset(){initView();removeAllViewsInLayout(); requestLayout();}@Overridepublic 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));}@Overrideprotected 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(){@Overridepublic 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();}@Overridepublic 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() {@Overridepublic boolean onDown(MotionEvent e) {return HorizontalListView.this.onDown(e);}@Overridepublic boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY) {return HorizontalListView.this.onFling(e1, e2, velocityX, velocityY);}@Overridepublic boolean onScroll(MotionEvent e1, MotionEvent e2,float distanceX, float distanceY) {synchronized(HorizontalListView.this){mNextX += (int)distanceX;}requestLayout();return true;}@Overridepublic 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;}@Overridepublic 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()); }};}