Android自定义ViewFlipper实现滚动效果

/** * Jiantao.Yang * * @description 仿百度手机助手，评论滚动效果 * @time 2015/1/16 17:37 */public class ViewFlipper extends LinearLayout {  private final int MAX_SHOW_ITEM_SIZE = 5;  private IAdapter mIAdapter;  private int mCount;  //最后一个item动画 private Animation mLastOneAnimation;  //其它item动画 private Animation mCommonAnimation;  //数据下标 private int mCurrentIndex;  /**  * 这里动画时间是1600毫秒，所以间隔得大于动画时间  */ private static final int DEFAULT_INTERVAL = 2000;  private int mFlipInterval = DEFAULT_INTERVAL;  private boolean mAutoStart = false;  private boolean mRunning = false; private boolean mStarted = false; private boolean mVisible = false; private boolean mUserPresent = true;  public ViewFlipper(Context context) {  super(context);  init(context); }  public ViewFlipper(Context context, AttributeSet attrs) {  super(context, attrs);  init(context); }  public ViewFlipper(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  init(context); }  private final BroadcastReceiver mReceiver = new BroadcastReceiver() {  @Override  public void onReceive(Context context, Intent intent) {   final String action = intent.getAction();   if (Intent.ACTION_SCREEN_OFF.equals(action)) {    mUserPresent = false;    updateRunning();   } else if (Intent.ACTION_USER_PRESENT.equals(action)) {    mUserPresent = true;    updateRunning(false);   }  } };  @Override protected void onAttachedToWindow() {  super.onAttachedToWindow();   // Listen for broadcasts related to user-presence  final IntentFilter filter = new IntentFilter();  filter.addAction(Intent.ACTION_SCREEN_OFF);  filter.addAction(Intent.ACTION_USER_PRESENT);   // OK, this is gross but needed. This class is supported by the  // remote views machanism and as a part of that the remote views  // can be inflated by a context for another user without the app  // having interact users permission - just for loading resources.  // For exmaple, when adding widgets from a user profile to the  // home screen. Therefore, we register the receiver as the current  // user not the one the context is for.  getContext().registerReceiver(mReceiver, filter);   if (mAutoStart) {   // Automatically start when requested   startFlipping();  } }  @Override protected void onDetachedFromWindow() {  super.onDetachedFromWindow();  mVisible = false;   getContext().unregisterReceiver(mReceiver);  updateRunning(); }  @Override protected void onWindowVisibilityChanged(int visibility) {  super.onWindowVisibilityChanged(visibility);  mVisible = visibility == VISIBLE;  updateRunning(mVisible);//  updateRunning(false); }  private void init(Context context) {  this.setOrientation(LinearLayout.VERTICAL); }  public void setIAdapter(IAdapter iAdapter) {  this.mIAdapter = iAdapter;  initShowItems(); }  public void startFlipping() {  mStarted = true;  updateRunning(); }  public void stopFlipping() {  mStarted = false;  updateRunning(); }  private void updateRunning() {  updateRunning(true); }  /**  * Returns true if the child views are flipping.  */ public boolean isFlipping() {  return mStarted; }  /**  * Set if this view automatically calls {@link #startFlipping()} when it  * becomes attached to a window.  */ public void setAutoStart(boolean autoStart) {  mAutoStart = autoStart; }  /**  * Returns true if this view automatically calls {@link #startFlipping()}  * when it becomes attached to a window.  */ public boolean isAutoStart() {  return mAutoStart; }  @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) {  super.onInitializeAccessibilityEvent(event);  event.setClassName(ViewFlipper.class.getName()); }  @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {  super.onInitializeAccessibilityNodeInfo(info);  info.setClassName(ViewFlipper.class.getName()); }  /**  * 初始化childViews  */ private void initShowItems() {  if (mIAdapter != null) {   mCount = mIAdapter.getCount();   for (int i = 0; i < mCount; i++) {    if (i == MAX_SHOW_ITEM_SIZE) {     break;    }    View convertView = getChildAt(i);    View item = mIAdapter.getItemView(convertView, i);    addView(item, i);   }  } }  /**  * Internal method to start or stop dispatching flip {@link android.os.Message} based  * on {@link #mRunning} and {@link #mVisible} state.  *  * @param flipNow Determines whether or not to execute the animation now, in  *    addition to queuing future flips. If omitted, defaults to  *    true.  */ private void updateRunning(boolean flipNow) {  boolean running = mVisible && mStarted && mUserPresent;  System.out.println(" updateRunning running:" + running + " mVisible " + mVisible + " userPresent " + mUserPresent);  if (running != mRunning) {   if (running && (mCount > MAX_SHOW_ITEM_SIZE)) {    showItems(mCurrentIndex++, flipNow);    Message msg = mHandler.obtainMessage(FLIP_MSG);    mHandler.sendMessageDelayed(msg, mFlipInterval);   } else {    mHandler.removeMessages(FLIP_MSG);   }   mRunning = running;  } }   private void showItems(final int position, boolean animate) {  if (animate && (mLastOneAnimation == null || mCommonAnimation == null)) {   mLastOneAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.lastone_anim);   mCommonAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.common_anim);  }  int childCount = getChildCount();  for (int i = 0; i < childCount; i++) {   View child = getChildAt(i);   child.clearAnimation();   int index = position + i;   child = mIAdapter.getItemView(child, (index >= mIAdapter.getCount()) ? (index - mIAdapter.getCount()) : index);   if (animate) {    if (i == childCount - 1) {     child.setAnimation(mLastOneAnimation);    } else {     child.setAnimation(mCommonAnimation);    }   }   child.setVisibility(View.VISIBLE);  }  if (animate) {   mCommonAnimation.startNow();   mLastOneAnimation.startNow();  }   //保证传入的position小于getCount  if (mCurrentIndex >= mIAdapter.getCount()) {   mCurrentIndex = 0;  } }  private final int FLIP_MSG = 1;  private final Handler mHandler = new Handler() {  @Override  public void handleMessage(Message msg) {   if (msg.what == FLIP_MSG) {    if (mRunning) {     showItems(mCurrentIndex++, true);     msg = obtainMessage(FLIP_MSG);     sendMessageDelayed(msg, mFlipInterval);    }   }  } };  public interface IAdapter {   /**   * @param convertView   * @param position   * @return   */  public View getItemView(View convertView, int position);   /**   * @return 数据count   */  public int getCount();  } }

public class MainActivity extends ActionBarActivity implements ViewFlipper.IAdapter {  ViewFlipper viewFlipper;  @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  viewFlipper = (ViewFlipper) findViewById(R.id.view_flipper);  viewFlipper.setIAdapter(this); }  @Override protected void onResume() {  super.onResume();  viewFlipper.startFlipping(); }  @Override public View getItemView(View convertView, int position) {  View item = null;  TextView textView;  if (convertView == null) {   item = View.inflate(this, R.layout.item, null);  } else {   item = convertView;  }  textView = (TextView) item.findViewById(R.id.textview);  textView.setText("测试数据:" + position);  return item; }  @Override public int getCount() {  return 8; }}