使用示例-代码
public class MainActivity extends Activity {
private ViewHolder mViewHolder;
private List<Integer> mDatas = new ArrayList<Integer>(Arrays.asList(R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e,
R.drawable.f, R.drawable.g, R.drawable.h, R.drawable.l));
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout mGallery = (LinearLayout) findViewById(R.id.id_gallery);
for (int i = 0; i < mDatas.size(); i++) {
View view = LayoutInflater.from(this).inflate(R.layout.item, mGallery, false);
((ImageView) view.findViewById(R.id.iv)).setImageResource(mDatas.get(i));
((TextView) view.findViewById(R.id.tv)).setText("some info ");
mGallery.addView(view);
}
((MyHorizontalScrollView) findViewById(R.id.horizontalScrollView)).initDatas(new HorizontalScrollViewAdapter(this, mDatas));
((MyHorizontalListView) findViewById(R.id.horizontalListview)).setAdapter(new MyBaseAdapter(this, mDatas));
}
//******************************************************************************************
public class HorizontalScrollViewAdapter {
private Context mContext;
private List<Integer> mList;
public HorizontalScrollViewAdapter(Context context, List<Integer> mDatas) {
this.mContext = context;
this.mList = mDatas;
}
public int getCount() {
return mList.size();
}
public Object getItem(int position) {
return mList.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
Log.i("bqt", "11111++++++" + position);
if (convertView == null) {
mViewHolder = new ViewHolder();
convertView = LayoutInflater.from(mContext).inflate(R.layout.item, parent, false);
mViewHolder.iv_head = (ImageView) convertView.findViewById(R.id.iv);
mViewHolder.tv_name = (TextView) convertView.findViewById(R.id.tv);
convertView.setTag(mViewHolder);
} else {
mViewHolder = (ViewHolder) convertView.getTag();
}
mViewHolder.iv_head.setImageResource(mList.get(position));
mViewHolder.tv_name.setText("some info ");
return convertView;
}
}
//******************************************************************************************
public class MyBaseAdapter extends BaseAdapter {
private Context mContext;
private List<Integer> mList;
public MyBaseAdapter(Context mContext, List<Integer> mList) {
this.mContext = mContext;
this.mList = mList;
}
@Override
public int getCount() {
return mList == null ? 0 : mList.size();
}
@Override
public Object getItem(int position) {
return mList == null ? null : mList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
Log.i("bqt", "22222++++++" + position);
if (convertView != null) {
mViewHolder = (ViewHolder) convertView.getTag();
} else {
convertView = LayoutInflater.from(mContext).inflate(R.layout.item, null);
mViewHolder = new ViewHolder();
mViewHolder.iv_head = (ImageView) convertView.findViewById(R.id.iv);
mViewHolder.tv_name = (TextView) convertView.findViewById(R.id.tv);
convertView.setTag(mViewHolder);
}
mViewHolder.iv_head.setImageResource(mList.get(position));
mViewHolder.tv_name.setText("some info ");
return convertView;
}
}
//******************************************************************************************
private static class ViewHolder {
public ImageView iv_head;
public TextView tv_name;
}
}
使用示例-布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white"
android:orientation="vertical" >
<HorizontalScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:background="#000"
android:paddingBottom="5dp"
android:paddingTop="5dp"
android:scrollbars="none" >
<LinearLayout
android:id="@+id/id_gallery"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:background="#000"
android:orientation="horizontal" />
</HorizontalScrollView>
<com.bqt.horizontalscrollview.MyHorizontalScrollView
android:id="@+id/horizontalScrollView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:background="#000"
android:paddingBottom="5dp"
android:paddingTop="5dp"
android:scrollbars="none" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:orientation="horizontal" />
</com.bqt.horizontalscrollview.MyHorizontalScrollView>
<!-- 这个自定义控件宽高属性没做处理，所以必须设置指定大小的高度，否则就是match_parent -->
<com.bqt.horizontalscrollview.MyHorizontalListView
android:id="@+id/horizontalListview"
android:layout_width="match_parent"
android:layout_height="118dp"
android:layout_marginTop="5dp"
android:background="#000"
android:paddingBottom="5dp"
android:paddingTop="5dp" />
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="120dp"
android:layout_height="130dp"
android:background="@android:color/white" >
<ImageView
android:id="@+id/iv"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_margin="5dp"
android:scaleType="centerCrop" />
<TextView
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/iv"
android:layout_centerHorizontal="true"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:textColor="#0000ff"
android:textSize="13sp" />
</RelativeLayout>
方式一、直接使用HorizontalScrollView
自从Gallery被谷歌废弃以后，Google推荐使用ViewPager和HorizontalScrollView来实现Gallery的效果。虽然HorizontalScrollView可以实现Gallery的效果，但是它存在一个很大的问题：
不管里面多少View都是不会回收的，当达到一定量的时候会发生OOM。
如果你仅是用来展示少量的图片，应该是没问题的，但是如果希望HorizontalScrollView可以像ViewPager一样，既可以绑定数据集（动态改变图片），还能做到，不管多少图片都不会OOM（ViewPager内部一直初始化、回收，至多只保持3个View）
，就需要
自定义了。
方式二、自定义HorizontalScrollView
import com.bqt.horizontalscrollview.MainActivity.HorizontalScrollViewAdapter;
public class MyHorizontalScrollView extends HorizontalScrollView implements OnClickListener {
/**
* 图片滚动时的回调接口
*/
public interface CurrentImageChangeListener {
void onCurrentImgChanged(int position, View viewIndicator);
}
/**
* 条目点击时的回调
*/
public interface OnItemClickListener {
void onClick(View view, int pos);
}
private CurrentImageChangeListener mListener;
private OnItemClickListener mOnClickListener;
private static final String TAG = "MyHorizontalScrollView";
/**
* HorizontalListView中的LinearLayout
*/
private LinearLayout mContainer;
/**
* 子元素的宽度
*/
private int mChildWidth;
/**
* 子元素的高度
*/
private int mChildHeight;
/**
* 当前最后一张图片的index
*/
private int mCurrentIndex;
/**
* 当前第一张图片的下标
*/
private int mFristIndex;
/**
* 当前第一个View
*/
private View mFirstView;
/**
* 数据适配器
*/
private HorizontalScrollViewAdapter mAdapter;
/**
* 每屏幕最多显示的个数
*/
private int mCountOneScreen;
/**
* 屏幕的宽度
*/
private int mScreenWitdh;
/**
* 保存View与位置的键值对
*/
private Map<View, Integer> mViewPos = new HashMap<View, Integer>();
public MyHorizontalScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
// 获得屏幕宽度
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(outMetrics);
mScreenWitdh = outMetrics.widthPixels;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mContainer = (LinearLayout) getChildAt(0);
}
/**
* 加载下一张图片
*/
protected void loadNextImg() {
// 数组边界值计算
if (mCurrentIndex == mAdapter.getCount() - 1) {
return;
}
//移除第一张图片，且将水平滚动位置置0
scrollTo(0, 0);
mViewPos.remove(mContainer.getChildAt(0));
mContainer.removeViewAt(0);
//获取下一张图片，并且设置onclick事件，且加入容器中
View view = mAdapter.getView(++mCurrentIndex, null, mContainer);
view.setOnClickListener(this);
mContainer.addView(view);
mViewPos.put(view, mCurrentIndex);
//当前第一张图片小标
mFristIndex++;
//如果设置了滚动监听则触发
if (mListener != null) {
notifyCurrentImgChanged();
}
}
/**
* 加载前一张图片
*/
protected void loadPreImg() {
//如果当前已经是第一张，则返回
if (mFristIndex == 0) return;
//获得当前应该显示为第一张图片的下标
int index = mCurrentIndex - mCountOneScreen;
if (index >= 0) {
// mContainer = (LinearLayout) getChildAt(0);
//移除最后一张
int oldViewPos = mContainer.getChildCount() - 1;
mViewPos.remove(mContainer.getChildAt(oldViewPos));
mContainer.removeViewAt(oldViewPos);
//将此View放入第一个位置
View view = mAdapter.getView(index, null, mContainer);
mViewPos.put(view, index);
mContainer.addView(view, 0);
view.setOnClickListener(this);
//水平滚动位置向左移动view的宽度个像素
scrollTo(mChildWidth, 0);
//当前位置--，当前第一个显示的下标--
mCurrentIndex--;
mFristIndex--;
//回调
if (mListener != null) {
notifyCurrentImgChanged();
}
}
}
/**
* 滑动时的回调
*/
public void notifyCurrentImgChanged() {
//先清除所有的背景色，点击时会设置为蓝色
for (int i = 0; i < mContainer.getChildCount(); i++) {
mContainer.getChildAt(i).setBackgroundColor(Color.WHITE);
}
mListener.onCurrentImgChanged(mFristIndex, mContainer.getChildAt(0));
}
/**
* 初始化数据，设置数据适配器
*
* @param mAdapter
*/
public void initDatas(HorizontalScrollViewAdapter mAdapter) {
this.mAdapter = mAdapter;
mContainer = (LinearLayout) getChildAt(0);
// 获得适配器中第一个View
final View view = mAdapter.getView(0, null, mContainer);
mContainer.addView(view);
// 强制计算当前View的宽和高
if (mChildWidth == 0 && mChildHeight == 0) {
int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
view.measure(w, h);
mChildHeight = view.getMeasuredHeight();
mChildWidth = view.getMeasuredWidth();
Log.e(TAG, view.getMeasuredWidth() + "," + view.getMeasuredHeight());
mChildHeight = view.getMeasuredHeight();
// 计算每次加载多少个View
mCountOneScreen = (mScreenWitdh / mChildWidth == 0) ? mScreenWitdh / mChildWidth + 1 : mScreenWitdh / mChildWidth + 2;
Log.e(TAG, "mCountOneScreen = " + mCountOneScreen + " ,mChildWidth = " + mChildWidth);
}
//初始化第一屏幕的元素
initFirstScreenChildren(mCountOneScreen);
}
/**
* 加载第一屏的View
*
* @param mCountOneScreen
*/
public void initFirstScreenChildren(int mCountOneScreen) {
mContainer = (LinearLayout) getChildAt(0);
mContainer.removeAllViews();
mViewPos.clear();
for (int i = 0; i < mCountOneScreen; i++) {
View view = mAdapter.getView(i, null, mContainer);
view.setOnClickListener(this);
mContainer.addView(view);
mViewPos.put(view, i);
mCurrentIndex = i;
}
if (mListener != null) {
notifyCurrentImgChanged();
}
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_MOVE:
// Log.e(TAG, getScrollX() + "");
int scrollX = getScrollX();
// 如果当前scrollX为view的宽度，加载下一张，移除第一张
if (scrollX >= mChildWidth) {
loadNextImg();
}
// 如果当前scrollX = 0， 往前设置一张，移除最后一张
if (scrollX == 0) {
loadPreImg();
}
break;
}
return super.onTouchEvent(ev);
}
@Override
public void onClick(View v) {
if (mOnClickListener != null) {
for (int i = 0; i < mContainer.getChildCount(); i++) {
mContainer.getChildAt(i).setBackgroundColor(Color.WHITE);
}
mOnClickListener.onClick(v, mViewPos.get(v));
}
}
public void setOnItemClickListener(OnItemClickListener mOnClickListener) {
this.mOnClickListener = mOnClickListener;
}
public void setCurrentImageChangeListener(CurrentImageChangeListener mListener) {
this.mListener = mListener;
}
}
方式三、自定义AdapterView
public class MyHorizontalListView 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 MyHorizontalListView(Context context) {
this(context, null);
}
public MyHorizontalListView(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 (MyHorizontalListView.this) {
mDataChanged = true;
}
invalidate();
requestLayout();
}
@Override
public void onInvalidated() {
reset();
invalidate();
requestLayout();
}
};
@Override
public ListAdapter getAdapter() {
return mAdapter;
}
@Override
public View getSelectedView() {
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) {
}
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 (MyHorizontalListView.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 MyHorizontalListView.this.onDown(e);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
return MyHorizontalListView.this.onFling(e1, e2, velocityX, velocityY);
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
synchronized (MyHorizontalListView.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(MyHorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));
}
if (mOnItemSelected != null) {
mOnItemSelected.onItemSelected(MyHorizontalListView.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(MyHorizontalListView.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());
}
};
}