android ExpandableListView的下拉刷新实现
该控件的修改时根据PullToRefreshList的机制修改
下面是对ExpandableListView的扩展
package com.up91.gwy.view.componet;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import com.up91.gwy.R;
import android.content.Context;
import android.util.AttributeSet;
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.ExpandableListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
public class PullToRefreshExpandableListView
extends ExpandableListView
implements
OnScrollListener {
private static final String TAG = "PullToRefreshExpandableListView";
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 OnRefreshListener mOnRefreshListener;
private OnScrollListener mOnScrollListener;
private LayoutInflater mInflater;
private RelativeLayout mRefreshView;
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 mRefreshOriginalTopPadding;
private int mLastMotionY;
private boolean isInInitState;
public PullToRefreshExpandableListView(Context context) {
super(context);
init(context);
}
public PullToRefreshExpandableListView(Context context, AttributeSet attrs) {
super(context,attrs);
init(context);
}
public PullToRefreshExpandableListView(Context context,AttributeSet attrs, int defStyle) {
super(context,attrs,defStyle);
init(context);
}
private void init(Context 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 = (RelativeLayout) mInflater.inflate(R.layout.pull_to_refresh_header, this,false);
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);
super.setOnScrollListener(this);
measureView(mRefreshView);
mRefreshViewHeight = mRefreshView.getMeasuredHeight();
}
private void measureView(View child){
ViewGroup.LayoutParams p = child.getLayoutParams();
if(p == null){
p = new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT
);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0+0, p.width);
int lpHeight = p.height;
int childHeightSpec;
if(lpHeight > 0){
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
}else{
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec,childHeightSpec);
}
private class OnClickRefreshListener implements OnClickListener{
@Override
public void onClick(View v) {
if(mRefreshState != REFRESHING){
prepareForRefresh();
onRefresh();
}
}
}
public interface OnRefreshListener{
public void onRefresh();
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
setSelection(1);
}
@Override
public void setAdapter(ListAdapter adapter) {
super.setAdapter(adapter);
setSelection(1);
}
@Override
public void setOnScrollListener(OnScrollListener l) {
mOnScrollListener = l;
}
public void setOnRefreshListener(OnRefreshListener onRefreshListener){
mOnRefreshListener = onRefreshListener;
}
public void setLastUpdated(CharSequence lastUpdated){
if(lastUpdated != null){
mRefreshViewLastUpdated.setVisibility(View.VISIBLE);
mRefreshViewLastUpdated.setText(lastUpdated);
}else{
mRefreshViewLastUpdated.setVisibility(View.GONE);
}
}
public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY();
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) {
// Initiate the refresh
mRefreshState = REFRESHING;
prepareForRefresh();
onRefresh();
} else if (mRefreshView.getBottom() < mRefreshViewHeight
|| mRefreshView.getTop() < 0) {
// Abort refresh and scroll down below the refresh view
resetHeader();
setSelection(1);
}
}
break;
case MotionEvent.ACTION_DOWN:
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
applyHeaderPadding(event);
break;
}
return super.onTouchEvent(event);
}
private void applyHeaderPadding(MotionEvent ev) {
final int historySize = ev.getHistorySize();
// Workaround for getPointerCount() which is unavailable in 1.5
// (it's always 1 in 1.5)
int pointerCount = 1;
try {
Method method = MotionEvent.class.getMethod("getPointerCount");
pointerCount = (Integer)method.invoke(ev);
} catch (NoSuchMethodException e) {
pointerCount = 1;
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
System.err.println("unexpected " + e);
} catch (InvocationTargetException e) {
System.err.println("unexpected " + e);
}
for (int h = 0; h < historySize; h++) {
for (int p = 0; p < pointerCount; p++) {
if (mRefreshState == RELEASE_TO_REFRESH) {
if (isVerticalFadingEdgeEnabled()) {
setVerticalScrollBarEnabled(false);
}
int historicalY = 0;
try {
// For Android > 2.0
Method method = MotionEvent.class.getMethod(
"getHistoricalY", Integer.TYPE, Integer.TYPE);
historicalY = ((Float) method.invoke(ev, p, h)).intValue();
} catch (NoSuchMethodException e) {
// For Android < 2.0
historicalY = (int) (ev.getHistoricalY(h));
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
System.err.println("unexpected " + e);
} catch (InvocationTargetException e) {
System.err.println("unexpected " + e);
}
// Calculate the padding to apply, we divide by 1.7 to
// simulate a more resistant effect during pull.
int topPadding = (int) (((historicalY - mLastMotionY)
- mRefreshViewHeight) / 1.7);
mRefreshView.setPadding(
mRefreshView.getPaddingLeft(),
topPadding,
mRefreshView.getPaddingRight(),
mRefreshView.getPaddingBottom());
}
}
}
}
private void resetHeaderPadding() {
mRefreshView.setPadding(
mRefreshView.getPaddingLeft(),
mRefreshOriginalTopPadding,
mRefreshView.getPaddingRight(),
mRefreshView.getPaddingBottom());
}
private void resetHeader() {
if (mRefreshState != TAP_TO_REFRESH) {
mRefreshState = TAP_TO_REFRESH;
resetHeaderPadding();
// Set refresh view text to the pull label
mRefreshViewText.setText(R.string.pull_to_refresh_tap_label);
// Replace refresh drawable with arrow drawable
mRefreshViewImage.setImageResource(R.drawable.ic_pulltorefresh_arrow);
// Clear the full rotation animation
mRefreshViewImage.clearAnimation();
// Hide progress bar and arrow.
mRefreshViewImage.setVisibility(View.GONE);
mRefreshViewProgress.setVisibility(View.GONE);
}
}
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// When the refresh view is completely visible, change the text to say
// "Release to refresh..." and flip the arrow drawable.
if (mCurrentScrollState == SCROLL_STATE_TOUCH_SCROLL
&& mRefreshState != REFRESHING) {
if (firstVisibleItem == 0) {
mRefreshViewImage.setVisibility(View.VISIBLE);
if((mRefreshView.getBottom() > mRefreshViewHeight + 20
|| mRefreshView.getTop() >= 0)
&& mRefreshState == PULL_TO_REFRESH){
mRefreshViewText.setText(R.string.pull_to_refresh_release_label);
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mFlipAnimation);
mRefreshState = RELEASE_TO_REFRESH;
}else if(mRefreshState == RELEASE_TO_REFRESH
&&mRefreshView.getBottom() < mRefreshViewHeight + 20){
mRefreshViewImage.setVisibility(View.GONE);
resetHeader();
}else if(mRefreshView.getBottom() == mRefreshViewHeight
&& mRefreshState == TAP_TO_REFRESH){
//不作为
mRefreshViewImage.setVisibility(View.GONE);
resetHeader();
} else if(mRefreshView.getBottom() < mRefreshViewHeight + 20
&& mRefreshState == TAP_TO_REFRESH){
mRefreshViewText.setText(R.string.pull_to_refresh_pull_label);
mRefreshState = PULL_TO_REFRESH;
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mReverseFlipAnimation);
}
} else {
mRefreshViewImage.setVisibility(View.GONE);
resetHeader();
}
} else if (mCurrentScrollState == SCROLL_STATE_FLING
&& firstVisibleItem == 0
&& mRefreshState != REFRESHING) {
setSelection(1);
}
if (mOnScrollListener != null) {
mOnScrollListener.onScroll(view, firstVisibleItem,
visibleItemCount, totalItemCount);
}
}
public void onScrollStateChanged(AbsListView view, int scrollState) {
mCurrentScrollState = scrollState;
if (mOnScrollListener != null) {
mOnScrollListener.onScrollStateChanged(view, scrollState);
}
}
public void prepareForRefresh() {
resetHeaderPadding();
mRefreshViewImage.setVisibility(View.GONE);
// We need this hack, otherwise it will keep the previous drawable.
mRefreshViewImage.setImageDrawable(null);
mRefreshViewProgress.setVisibility(View.VISIBLE);
// Set refresh view text to the refreshing label
mRefreshViewText.setText(R.string.pull_to_refresh_refreshing_label);
mRefreshState = REFRESHING;
}
public void onRefresh() {
if (mOnRefreshListener != null) {
mOnRefreshListener.onRefresh();
resetHeader();
}
}
public void onRefreshComplete(CharSequence lastUpdated) {
setLastUpdated(lastUpdated);
onRefreshComplete();
}
public void onRefreshComplete() {
resetHeader();
// If refresh view is visible when loading completes, scroll down to
// the next item.
if (mRefreshView.getBottom() > 0) {
invalidateViews();
setSelection(1);
}
}
}
使用时：
expLV.setOnRefreshListener(new OnRefreshListener(){
@Override
public void onRefresh() {
//远程取数据机制
});