这篇文章主要介绍了Android中实现水平滑动(横向滑动)ListView示例,本文用自己封装一个控件的方法解决了这个需求,需要的朋友可以参考下
水平的ListView-HorizontalListView的使用
Android中ListView默认的是竖直方向的滑动,由于项目的需求,需要ListView是水平滑动的。有很多的方式可以实现,但是比较好的一种方式就是自己封装一个控件,使用方式和ListView的使用方式是一样的。需要完善的地方:获取到的图片大小没有处理。在界面上展示的是图片的原大小。为了更好的展示效果,应该压缩成统一的尺寸。
HorizontalListView.java 代码如下:
- /**
- * 横向的ListView
- *
- * * @author scd
- *
- */
- 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());
- }
- };
- }
适配器 HorizontalListViewAdapter .java如下:
- public class HorizontalListViewAdapter extends BaseAdapter {
- /** 上下文 */
- private Context mContext;
- /** 图像数据源 */
- private ArrayList<Map<String, Integer>> mImageList;
- /** 数据源 */
- private ArrayList<Map<String, Integer>> mTextList;
- /** Image */
- private static String IMAGE = "ic_";
- private Map<String, Integer> mMap = null;
- /** 构造方法 */
- public HorizontalListViewAdapter(Context context) {
- this.mContext = context;
- initData();
- }
- /** 初始化数据 */
- public void initData() {
- mImageList = new ArrayList<Map<String, Integer>>();
- /*
- * 反射技术
- */
- Class<?> imageClzz = R.drawable.class;
- R.drawable instance = new R.drawable();
- // 取得drawable类中所有的字段
- Field[] fields = imageClzz.getDeclaredFields();
- for (Field field : fields) {
- // 获得字段的名字
- String name = field.getName();
- if (name != null && name.startsWith(IMAGE)) {
- try {
- mMap = new HashMap<String, Integer>();
- mMap.put(IMAGE, (Integer) field.get(instance));
- mImageList.add(mMap);
- } catch (IllegalAccessException e) {
- e.printStackTrace();
- }
- }
- }
- }
- @Override
- public int getCount() {
- return mImageList.size();
- }
- @Override
- public Map<String, Integer> getItem(int position) {
- return mImageList == null ? null : mImageList.get(position);
- }
- @Override
- public long getItemId(int position) {
- return position;
- }
- @Override
- public View getView(int position, View convertView, ViewGroup parent) {
- ViewHolder holder;
- if (convertView == null) {
- holder = new ViewHolder();
- convertView = LayoutInflater.from(mContext).inflate(
- R.layout.horizontal_list_item, null);
- holder.mImage = (ImageView) convertView
- .findViewById(R.id.iv_list_item);
- holder.mTitle = (TextView) convertView
- .findViewById(R.id.tv_list_item);
- convertView.setTag(holder);
- } else {
- holder = (ViewHolder) convertView.getTag();
- }
- if (position == mSelectIndex) {
- convertView.setSelected(true);
- } else {
- convertView.setSelected(false);
- }
- holder.mImage.setImageResource(getItem(position).get(IMAGE));
- return convertView;
- }
- private class ViewHolder {
- /** 图像 */
- private ImageView mImage;
- }
- }
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