android像新浪微博一样的下拉刷新

package com.xj.test; import java.text.SimpleDateFormat; import java.util.Date; import android.app.Activity; import android.content.Context; import android.graphics.Color; import android.util.AttributeSet; import android.util.Log; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation; import android.widget.AbsListView; import android.widget.Adapter; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.AbsListView.OnScrollListener; public class PullToRefreshListView extends ListView implements OnScrollListener { private static final int TAP_TO_REFRESH = 1; private static final int PULL_TO_REFRESH = 2; private static final int RELEASE_TO_REFRESH = 3; private static final int REFRESHING = 4; private static final int LIST_ITEM_HEIGHT = 60; private static final String TAG = "PullToRefreshListView"; private OnRefreshListener mOnRefreshListener; public Activity context; /** * Listener that will receive notifications every time the list scrolls. */ private OnScrollListener mOnScrollListener; private LayoutInflater mInflater; private Adapter adapter; private boolean isFirstRun = true; private boolean isActionDown = true; private LinearLayout mRefreshView; private View footerView; private TextView mRefreshViewText; private ImageView mRefreshViewImage; private ProgressBar mRefreshViewProgress; private TextView mRefreshViewLastUpdated; private int mCurrentScrollState; private int mRefreshState; private RotateAnimation mFlipAnimation; private RotateAnimation mReverseFlipAnimation; private int mRefreshViewHeight; private int mFooterViewHeight; private int mRefreshOriginalTopPadding; private int mLastMotionY; private int mItemTotalHeight; private int mAdapterCount; private int mWindowHeight; public PullToRefreshListView(Context context) { super(context); init(context); } public PullToRefreshListView(Context context, AttributeSet attrs) { super(context, attrs); init(context); } public PullToRefreshListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context); } private void init(Context context) { // Load all of the animations we need in code rather than through XML this.context = (Activity)context; mFlipAnimation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f); mFlipAnimation.setInterpolator(new LinearInterpolator()); mFlipAnimation.setDuration(250); mFlipAnimation.setFillAfter(true); mReverseFlipAnimation = new RotateAnimation(-180, 0, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f); mReverseFlipAnimation.setInterpolator(new LinearInterpolator()); mReverseFlipAnimation.setDuration(250); mReverseFlipAnimation.setFillAfter(true); mInflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE); mRefreshView = (LinearLayout) mInflater.inflate(R.layout.public_pull_to_refresh_header, null); mRefreshViewText = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_text); mRefreshViewImage = (ImageView) mRefreshView.findViewById(R.id.pull_to_refresh_image); mRefreshViewProgress = (ProgressBar) mRefreshView.findViewById(R.id.pull_to_refresh_progress); mRefreshViewLastUpdated = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_updated_at); mRefreshViewImage.setMinimumHeight(50); mRefreshView.setOnClickListener(new OnClickRefreshListener()); mRefreshOriginalTopPadding = mRefreshView.getPaddingTop(); mRefreshState = TAP_TO_REFRESH; addHeaderView(mRefreshView); footerView = new View(context); footerView.setFocusable(false); footerView.setFocusableInTouchMode(false); footerView.setEnabled(false); footerView.setBackgroundColor(Color.WHITE); addFooterView(footerView); super.setOnScrollListener(this); measureView(mRefreshView); mRefreshViewHeight = mRefreshView.getMeasuredHeight(); } @Override protected void onAttachedToWindow() { setSelection(1); } public void setFooterHeight(){ Log.e("***setFooterHeight***", "***" + mFooterViewHeight + "***"); if(mFooterViewHeight > 0){ footerView.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.FILL_PARENT, mFooterViewHeight)); } else{ footerView.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.FILL_PARENT, 0)); } } @Override public void setAdapter(ListAdapter adapter) { this.adapter = adapter; int width = getWidth(); mWindowHeight = context.getWindowManager().getDefaultDisplay().getHeight(); Log.e("===setAdapter===", width + " * " + mWindowHeight); mAdapterCount = adapter.getCount(); mItemTotalHeight = mAdapterCount * LIST_ITEM_HEIGHT; mFooterViewHeight = mWindowHeight - mItemTotalHeight + mRefreshViewHeight; setFooterHeight(); super.setAdapter(adapter); setSelection(1); } /** * Set the listener that will receive notifications every time the list * scrolls. * * @param l The scroll listener. */ @Override public void setOnScrollListener(AbsListView.OnScrollListener l) { mOnScrollListener = l; } /** * Register a callback to be invoked when this list should be refreshed. * * @param onRefreshListener The callback to run. */ public void setOnRefreshListener(OnRefreshListener onRefreshListener) { mOnRefreshListener = onRefreshListener; } /** * Set a text to represent when the list was last updated. * @param lastUpdated Last updated at. */ public void setLastUpdated() { SimpleDateFormat sdf = new SimpleDateFormat(" MM/dd/yyyy HH:mm"); mRefreshViewLastUpdated.setText(context.getString(R.string.pull_to_refresh_last_update) + sdf.format(new Date())); } @Override public boolean onTouchEvent(MotionEvent event) { final int y = (int) event.getY(); int count = adapter.getCount(); View view = null; if(count > 0){ view = getChildAt(1); }else{ view = getChildAt(0); } switch (event.getAction()) { case MotionEvent.ACTION_UP: if (!isVerticalScrollBarEnabled()) { setVerticalScrollBarEnabled(true); } if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) { if ((mRefreshView.getBottom() > mRefreshViewHeight || mRefreshView.getTop() > 0) && mRefreshState == RELEASE_TO_REFRESH) { mRefreshState = REFRESHING; prepareForRefresh(); onRefresh(); } else if (mRefreshView.getBottom() < mRefreshViewHeight || mRefreshView.getTop() < 0) { resetHeader(); setSelection(1); } } break; case MotionEvent.ACTION_DOWN: mLastMotionY = y; if(isFirstRun){ isFirstRun = false;