android水平循环滚动控件使用详解

 package com.example.test; import android.content.Context; import android.graphics.Rect; import android.os.Handler; import android.util.AttributeSet; import android.view.GestureDetector; import android.view.GestureDetector.OnGestureListener; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.widget.Scroller; @SuppressWarnings("deprecation") public class CycleScrollView extends ViewGroup implements OnGestureListener { static final String TAG = "CycleScrollView"; Context mContext; /** * Scroll velocity. */ public static final long SCROLL_VELOCITY = 50; /** * Scroll offset. */ public static final int SCROLL_OFFSET = -1; /** * Touch delay. */ public static final long TOUCH_DELAYMILLIS = 2000; /** * Fling duration. */ public static final int FLING_DURATION = 2000; /** * Filing max velocity x. */ public static final int MAX_VELOCITY_X = 1000; private GestureDetector detector; private Handler mHandler; private Scroller mScroller; /** * Callback interface adapter and OnItemClick. */ private CycleScrollAdapter mAdapter; private OnItemClickListener mOnItemClickListener; /** * Scroll index */ private int mPreIndex; private int mCurrentIndex; private int mNextIndex; private View mCurrentView; private View mPreView; private View mNextView; private float mLastMotionX; // The reLayout is false can not invoke onLayout. private boolean reLayout = false; // If the item count more than screen that can scroll. private boolean canScroll = false; // A flag for switch current view. private boolean mCurrentViewAtLeft = true; // Fling distance. private int mFlingX = 0; private boolean isMoveAction = false; private int defaultItemY = 10; private int maxItemCount = 7; private int initItemX = 20; /** * The screen width. */ private int screenWidth; /** * Item view height. */ private int itemHeight; /** * Item view width. */ private int itemWidth; /** * Item view layout x. */ private int itemX = getInitItemX(); /** * Item view layout y. */ private int itemY = defaultItemY; // Auto scroll view task. private final Runnable mScrollTask = new Runnable() { @Override public void run() { if (canScroll) { scrollView(SCROLL_OFFSET); mHandler.postDelayed(this, SCROLL_VELOCITY);// Loop self. } } }; public CycleScrollView(Context context) { super(context); onCreate(context); } public CycleScrollView(Context context, AttributeSet attrs) { super(context, attrs); onCreate(context); } public CycleScrollView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); onCreate(context); } private void onCreate(Context context) { mContext = context; detector = new GestureDetector(this); mHandler = new Handler(); mScroller = new Scroller(context); } /** * Create scroll index. */ public void createIndex() { if (canScroll) { mPreIndex = maxItemCount - 1; mCurrentIndex = 0; mNextIndex = 1; mPreView = getChildAt(mPreIndex); mCurrentView = getChildAt(mCurrentIndex); mNextView = getChildAt(mNextIndex); } } /** * Set item click callback. * * @param onItemClickListener *   The callback */ public void setOnItemClickListener(OnItemClickListener onItemClickListener) { mOnItemClickListener = onItemClickListener; } /** * Set itemAdapter for addItem and bindItem. * * @param itemAdapter */ public void setAdapter(CycleScrollAdapter adapter) { mAdapter = adapter; } /** * Start auto scroll. */ public void startScroll() { if (canScroll) { mHandler.post(mScrollTask); } } /** * Stop auto scroll and filing scroll task. */ public void stopScroll() { mHandler.removeCallbacks(mScrollTask); } /** * Delay start auto scroll task. */ public void delayStartScroll() { if (canScroll) { mHandler.postDelayed(mScrollTask, TOUCH_DELAYMILLIS); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int count = this.getChildCount(); for (int i = 0; i  maxItemCount - 1) { mNextIndex = 0; } mCurrentView = getChildAt(mCurrentIndex); mPreView = getChildAt(mPreIndex); mNextView = getChildAt(mNextIndex); mCurrentViewAtLeft = !mCurrentViewAtLeft; } } /** * Current event is move to right, if current view at left switch current * view to right. */ private void switchCurrentViewToRight() { if (mCurrentViewAtLeft) { mNextIndex = mCurrentIndex; mCurrentIndex = mPreIndex; mPreIndex--; if (mPreIndex <0) { mPreIndex = maxItemCount - 1; } mCurrentView = getChildAt(mCurrentIndex); mPreView = getChildAt(mPreIndex); mNextView = getChildAt(mNextIndex); mCurrentViewAtLeft = !mCurrentViewAtLeft; } } /** * Current event is move to left,if current view move out of screen move the * current view to right and reBind the item change index. */ private void moveToNext() { if (mCurrentView.getRight() <0) { mCurrentView.layout(mPreView.getLeft() + getItemMargin(), getItemY(), mPreView.getLeft() + getItemMargin() + getItemWidth(), getItemY() + getItemHeight()); if (mCurrentView.getTag() != null) { int listIndex = (Integer) mCurrentView.getTag(); int index = (listIndex + maxItemCount) % mAdapter.getCount(); mAdapter.bindView(mCurrentView, mAdapter.get(index)); mCurrentView.setTag(index); } mPreIndex = mCurrentIndex; mCurrentIndex = mNextIndex; mNextIndex++; if (mNextIndex > maxItemCount - 1) { mNextIndex = 0; } mCurrentView = getChildAt(mCurrentIndex); mPreView = getChildAt(mPreIndex); mNextView = getChildAt(mNextIndex); moveToNext(); } } /** * Current event is move to right,if current view move out of screen move * the current view to left and reBind the item change index. */ private void moveToPre() { if (mCurrentView.getLeft() > getScreenWidth()) { mCurrentView.layout(mNextView.getLeft() - getItemMargin(), getItemY(), mNextView.getLeft() - getItemMargin() + getItemWidth(), getItemY() + getItemHeight()); if (mCurrentView.getTag() != null) { int listIndex = (Integer) mCurrentView.getTag(); int index = (listIndex - maxItemCount + mAdapter.getCount()) % mAdapter.getCount(); mAdapter.bindView(mCurrentView, mAdapter.get(index)); mCurrentView.setTag(index); } mNextIndex = mCurrentIndex; mCurrentIndex = mPreIndex; mPreIndex--; if (mPreIndex <0) { mPreIndex = maxItemCount - 1; } mCurrentView = getChildAt(mCurrentIndex); mPreView = getChildAt(mPreIndex); mNextView = getChildAt(mNextIndex); moveToPre(); } } @Override public boolean onDown(MotionEvent e) { return true; } @Override public void onShowPress(MotionEvent e) { } @Override public boolean onSingleTapUp(MotionEvent e) { return false; } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { return false; } @Override public void onLongPress(MotionEvent e) { } public int getMaxItemCount() { return maxItemCount; } public void setMaxItemCount(int maxItemCount) { this.maxItemCount = maxItemCount; } public void setReLayout(boolean reLayout) { this.reLayout = reLayout; } public void setCanScroll(boolean canScroll) { this.canScroll = canScroll; } public int getItemX() { return itemX; } public void setItemX(int itemX) { this.itemX = itemX; } public int getItemY() { return itemY; } public void setItemY(int itemY) { this.itemY = itemY; } public int getItemWidth() { return itemWidth; } public void setItemWidth(int itemWidth) { this.itemWidth = itemWidth; } public int getItemHeight() { return itemHeight; } public void setItemHeight(int itemHeight) { this.itemHeight = itemHeight; } public int getItemMargin() { return (screenWidth - itemWidth * (maxItemCount - 1) - initItemX * 2)/(maxItemCount - 2) + itemWidth; } public int getScreenWidth() { return screenWidth; } public void setScreenWidth(int screenWidth) { this.screenWidth = screenWidth; } public int getInitItemX() { return initItemX; } public void setInitItemX(int initItemX) { this.initItemX = initItemX; } /** * The interface for item click callback. */ interface OnItemClickListener { public boolean onItemClick(int position); } } 

 package com.example.test; import java.util.List; import android.app.Activity; import android.content.Context; import android.util.DisplayMetrics; import android.view.View; public abstract class CycleScrollAdapter { private List list; private CycleScrollView mCycleScrollView; Context mContext; /** * Initial CycleScrollAdapter bind list to view. * * @param list *   The list data. * @param cycleScrollView *   The CycleScrollView. * @param context *   The Context. */ public CycleScrollAdapter(List list, CycleScrollView cycleScrollView, Context context) { this.list = list; mContext = context; mCycleScrollView = cycleScrollView; mCycleScrollView.setAdapter(this); GetScreenWidthPixels(); initView(list); } /** * Get screen width pixels. */ private void GetScreenWidthPixels() { DisplayMetrics dm = new DisplayMetrics(); Activity a = (Activity) mContext; a.getWindowManager().getDefaultDisplay().getMetrics(dm); mCycleScrollView.setScreenWidth(dm.widthPixels); } /** * Bind list to view. * * @param list *   The list data. */ protected void initView(List list) { if (list == null || list.size() == 0) { return; } // Clear all view from ViewGroup at first. mCycleScrollView.removeAllViewsInLayout(); // Loop list. for (int i = 0; i = mCycleScrollView.getMaxItemCount()) { mCycleScrollView.setCanScroll(true); } else { mCycleScrollView.setCanScroll(false); } /** * If list count more than MaxItemCount reBuild index. */ mCycleScrollView.createIndex(); } /** * Get list size. * * @return The list size. */ public int getCount() { return list.size(); } /** * Returns the element at the specified location in this * * @param index *   the index of the element to return. * @return the element at the specified location. */ public T get(int index) { return list.get(index); } /** * Adds the specified object at the end of this and refresh view. * * @param t *   the object to add. */ public void addItem(T t) { list.add(t); initView(list); } /** * Removes the first occurrence of the specified object from this and * refresh view. * * @param t *   the object to remove. */ public void removeItem(T t) { list.remove(t); initView(list); } /** * Add the specified view to the index. * * @param t *   The data to add. * @param index *   the index. */ private void add(T t, int index) { View view = getView(t); ComputeItemSize(view); mCycleScrollView.addView(view); view.setTag(index); } /** * If item size is null compute item size. * * @param view *   the item view. */ private void ComputeItemSize(View view) { if (mCycleScrollView.getItemWidth() == 0 || mCycleScrollView.getItemHeight() == 0) { int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED); view.measure(w, h); int height = view.getMeasuredHeight(); int width = view.getMeasuredWidth(); mCycleScrollView.setItemHeight(height); mCycleScrollView.setItemWidth(width); } } /** * Get item view. * * @param t *   the data need bind to view. * @return the view. */ public abstract View getView(T t); /** * Bind the item to view. * * @param child *   the item view need bind. * @param t *   the item. */ public abstract void bindView(View child, T t); } 

 package com.example.test; import java.util.List; import android.content.Context; import android.content.pm.PackageInfo; import android.view.View; import android.widget.ImageView; import android.widget.TextView; public class AppCycleScrollAdapter extends CycleScrollAdapter { public AppCycleScrollAdapter(List list, CycleScrollView cycleScrollView, Context context) { super(list, cycleScrollView, context); } @Override protected void initView(List list) { super.initView(list); } @Override public void bindView(View child, PackageInfo pi) { ImageView image = (ImageView) child.findViewById(R.id.item_image); TextView text = (TextView) child.findViewById(R.id.item_text); image.setImageDrawable(pi.applicationInfo.loadIcon(mContext .getPackageManager())); text.setText(pi.applicationInfo.loadLabel(mContext.getPackageManager())); } @Override public View getView(PackageInfo pi) { View view = View.inflate(mContext, R.layout.view_item, null); // inflate APP icon view ImageView image = (ImageView) view.findViewById(R.id.item_image); // inflate APP name view TextView text = (TextView) view.findViewById(R.id.item_text); image.setImageDrawable(pi.applicationInfo.loadIcon(mContext .getPackageManager())); text.setText(pi.applicationInfo.loadLabel(mContext.getPackageManager())); return view; } } 

 package com.example.test; import java.util.List; import android.app.Activity; import android.content.pm.PackageInfo; import android.os.Bundle; import android.view.Menu; public class MainActivity extends Activity{ private CycleScrollView mCycleScrollView; private AppCycleScrollAdapter mAdapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mCycleScrollView = ((CycleScrollView) this.findViewById(R.id.cycle_scroll_view)); /** * Get APP list and sort by update time. */ List list = this.getPackageManager() .getInstalledPackages(0); mAdapter = new AppCycleScrollAdapter(list, mCycleScrollView, this); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.activity_main, menu); return true; } } 

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