我在我的应用程序中使用 pulltorefresh。在 onRefresh() 中，我尝试通过保留 listView.setAdapter(null); 来删除所有项目；
但我的 listView.getCount() 仍然返回 1。
listView.setOnRefreshListener(new OnRefreshListener() {
// @Override
public void onRefresh() {
// Your code to refresh the list contents goes here
scroll=true;
pic.clear();
id.clear();
name.clear();
msg.clear();
img.clear();
profimg.clear();
objid.clear();
comment.clear();
weburl.clear();
adapter.clear();
likes.clear();
like_or_unlike.clear();
previousTotal = 0;
adapter.clear();
j=0;
loading = true;
webserv="https://graph.facebook.com/me/home?access_token="+accesstoken;
// listView.setAdapter(null);
System.out.println(listView.getCount());
// doInBack dob=new doInBack();
// dob.execute();
System.out.println(listView.getCount());
doback(webserv);
Log.e("hi","doback called");
}
});
我的 pulltorefresh 课程是
package com.beerbro.utils;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.*;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.animation.*;
import android.view.animation.Animation.AnimationListener;
import android.widget.*;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* A generic, customizable Android ListView implementation that has 'Pull to Refresh' functionality.
* <p/>
* This ListView can be used in place of the normal Android android.widget.ListView class.
* <p/>
* Users of this class should implement OnRefreshListener and call setOnRefreshListener(..)
* to get notified on refresh events. The using class should call onRefreshComplete() when
* refreshing is finished.
* <p/>
* The using class can call setRefreshing() to set the state explicitly to refreshing. This
* is useful when you want to show the spinner and 'Refreshing' text when the
* refresh was not triggered by 'Pull to Refresh', for example on start.
* <p/>
* For more information, visit the project page:
* https://github.com/erikwt/PullToRefresh-ListView
*
* @author Erik Wallentinsen <dev+ptr@erikw.eu>
* @version 1.0.0
*/
public class PullToRefreshListView extends ListView{
private static final float PULL_RESISTANCE = 1.7f;
private static final int BOUNCE_ANIMATION_DURATION = 700;
private static final int BOUNCE_ANIMATION_DELAY = 100;
private static final float BOUNCE_OVERSHOOT_TENSION = 1.4f;
private static final int ROTATE_ARROW_ANIMATION_DURATION = 250;
private static enum State{
PULL_TO_REFRESH,
RELEASE_TO_REFRESH,
REFRESHING
}
/**
* Interface to implement when you want to get notified of 'pull to refresh'
* events.
* Call setOnRefreshListener(..) to activate an OnRefreshListener.
*/
public interface OnRefreshListener{
/**
* Method to be called when a refresh is requested
*/
public void onRefresh();
}
private static int measuredHeaderHeight;
private boolean scrollbarEnabled;
private boolean bounceBackHeader;
private boolean lockScrollWhileRefreshing;
private boolean showLastUpdatedText;
private String pullToRefreshText;
private String releaseToRefreshText;
private String refreshingText;
private String lastUpdatedText;
private SimpleDateFormat lastUpdatedDateFormat = new SimpleDateFormat("dd/MM HH:mm");
private float previousY;
private int headerPadding;
private boolean hasResetHeader;
private long lastUpdated = -1;
private State state;
private LinearLayout headerContainer;
private RelativeLayout header;
private RotateAnimation flipAnimation;
private RotateAnimation reverseFlipAnimation;
private ImageView image;
private ProgressBar spinner;
private TextView text;
private TextView lastUpdatedTextView;
private OnItemClickListener onItemClickListener;
private OnItemLongClickListener onItemLongClickListener;
private OnRefreshListener onRefreshListener;
public PullToRefreshListView(Context context){
super(context);
init();
}
public PullToRefreshListView(Context context, AttributeSet attrs){
super(context, attrs);
init();
}
public PullToRefreshListView(Context context, AttributeSet attrs, int defStyle){
super(context, attrs, defStyle);
init();
}
@Override
public void setOnItemClickListener(OnItemClickListener onItemClickListener){
this.onItemClickListener = onItemClickListener;
}
@Override
public void setOnItemLongClickListener(OnItemLongClickListener onItemLongClickListener){
this.onItemLongClickListener = onItemLongClickListener;
}
/**
* Activate an OnRefreshListener to get notified on 'pull to refresh'
* events.
*
* @param onRefreshListener The OnRefreshListener to get notified
*/
public void setOnRefreshListener(OnRefreshListener onRefreshListener){
this.onRefreshListener = onRefreshListener;
}
/**
* @return If the list is in 'Refreshing' state
*/
public boolean isRefreshing(){
return state == State.REFRESHING;
}
/**
* Default is false. When lockScrollWhileRefreshing is set to true, the list
* cannot scroll when in 'refreshing' mode. It's 'locked' on refreshing.
*
* @param lockScrollWhileRefreshing
*/
public void setLockScrollWhileRefreshing(boolean lockScrollWhileRefreshing){
this.lockScrollWhileRefreshing = lockScrollWhileRefreshing;
}
/**
* Default is false. Show the last-updated date/time in the 'Pull ro Refresh'
* header. See 'setLastUpdatedDateFormat' to set the date/time formatting.
*
* @param showLastUpdatedText
*/
public void setShowLastUpdatedText(boolean showLastUpdatedText){
this.showLastUpdatedText = showLastUpdatedText;
if(!showLastUpdatedText) lastUpdatedTextView.setVisibility(View.GONE);
}
/**
* Default: "dd/MM HH:mm". Set the format in which the last-updated
* date/time is shown. Meaningless if 'showLastUpdatedText == false (default)'.
* See 'setShowLastUpdatedText'.
*
* @param lastUpdatedDateFormat
*/
public void setLastUpdatedDateFormat(SimpleDateFormat lastUpdatedDateFormat){
this.lastUpdatedDateFormat = lastUpdatedDateFormat;
}
/**
* Explicitly set the state to refreshing. This
* is useful when you want to show the spinner and 'Refreshing' text when
* the refresh was not triggered by 'pull to refresh', for example on start.
*/
public void setRefreshing(){
state = State.REFRESHING;
scrollTo(0, 0);
setUiRefreshing();
setHeaderPadding(0);
}
/**
* Set the state back to 'pull to refresh'. Call this method when refreshing
* the data is finished.
*/
public void onRefreshComplete(){
state = State.PULL_TO_REFRESH;
resetHeader();
lastUpdated = System.currentTimeMillis();
}
/**
* Change the label text on state 'Pull to Refresh'
*
* @param pullToRefreshText Text
*/
public void setTextPullToRefresh(String pullToRefreshText){
this.pullToRefreshText = pullToRefreshText;
if(state == State.PULL_TO_REFRESH){
text.setText(pullToRefreshText);
}
}
/**
* Change the label text on state 'Release to Refresh'
*
* @param releaseToRefreshText Text
*/
public void setTextReleaseToRefresh(String releaseToRefreshText){
this.releaseToRefreshText = releaseToRefreshText;
if(state == State.RELEASE_TO_REFRESH){
text.setText(releaseToRefreshText);
}
}
/**
* Change the label text on state 'Refreshing'
*
* @param refreshingText Text
*/
public void setTextRefreshing(String refreshingText){
this.refreshingText = refreshingText;
if(state == State.REFRESHING){
text.setText(refreshingText);
}
}
private void init(){
setVerticalFadingEdgeEnabled(false);
headerContainer = (LinearLayout) LayoutInflater.from(getContext()).inflate(R.layout.ptr_header, null);
header = (RelativeLayout) headerContainer.findViewById(R.id.ptr_id_header);
text = (TextView) header.findViewById(R.id.ptr_id_text);
lastUpdatedTextView = (TextView) header.findViewById(R.id.ptr_id_last_updated);
image = (ImageView) header.findViewById(R.id.ptr_id_image);
spinner = (ProgressBar) header.findViewById(R.id.ptr_id_spinner);
pullToRefreshText = getContext().getString(R.string.ptr_pull_to_refresh);
releaseToRefreshText = getContext().getString(R.string.ptr_release_to_refresh);
refreshingText = getContext().getString(R.string.ptr_refreshing);
lastUpdatedText = getContext().getString(R.string.ptr_last_updated);
flipAnimation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
flipAnimation.setInterpolator(new LinearInterpolator());
flipAnimation.setDuration(ROTATE_ARROW_ANIMATION_DURATION);
flipAnimation.setFillAfter(true);
reverseFlipAnimation = new RotateAnimation(-180, 0, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
reverseFlipAnimation.setInterpolator(new LinearInterpolator());
reverseFlipAnimation.setDuration(ROTATE_ARROW_ANIMATION_DURATION);
reverseFlipAnimation.setFillAfter(true);
addHeaderView(headerContainer);
setState(State.PULL_TO_REFRESH);
scrollbarEnabled = isVerticalScrollBarEnabled();
ViewTreeObserver vto = header.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new PTROnGlobalLayoutListener());
super.setOnItemClickListener(new PTROnItemClickListener());
super.setOnItemLongClickListener(new PTROnItemLongClickListener());
}
private void setHeaderPadding(int padding){
headerPadding = padding;
MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams) header.getLayoutParams();
mlp.setMargins(0, Math.round(padding), 0, 0);
header.setLayoutParams(mlp);
}
@Override
public boolean onTouchEvent(MotionEvent event){
if(lockScrollWhileRefreshing
&& (state == State.REFRESHING || getAnimation() != null && !getAnimation().hasEnded())){
return true;
}
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
if(getFirstVisiblePosition() == 0) previousY = event.getY();
else previousY = -1;
break;
case MotionEvent.ACTION_UP:
if(previousY != -1 && (state == State.RELEASE_TO_REFRESH || getFirstVisiblePosition() == 0)){
switch(state){
case RELEASE_TO_REFRESH:
setState(State.REFRESHING);
bounceBackHeader();
break;
case PULL_TO_REFRESH:
resetHeader();
break;
}
}
break;
case MotionEvent.ACTION_MOVE:
if(previousY != -1){
float y = event.getY();
float diff = y - previousY;
if(diff > 0) diff /= PULL_RESISTANCE;
previousY = y;
int newHeaderPadding = Math.max(Math.round(headerPadding + diff), -header.getHeight());
if(newHeaderPadding != headerPadding && state != State.REFRESHING){
setHeaderPadding(newHeaderPadding);
if(state == State.PULL_TO_REFRESH && headerPadding > 0){
setState(State.RELEASE_TO_REFRESH);
image.clearAnimation();
image.startAnimation(flipAnimation);
}else if(state == State.RELEASE_TO_REFRESH && headerPadding < 0){
setState(State.PULL_TO_REFRESH);
image.clearAnimation();
image.startAnimation(reverseFlipAnimation);
}
return true;
}
}
break;
}
return super.onTouchEvent(event);
}
private void bounceBackHeader(){
int yTranslate = state == State.REFRESHING ?
header.getHeight() - headerContainer.getHeight() :
-headerContainer.getHeight() - headerContainer.getTop();
TranslateAnimation bounceAnimation = new TranslateAnimation(
TranslateAnimation.ABSOLUTE, 0,
TranslateAnimation.ABSOLUTE, 0,
TranslateAnimation.ABSOLUTE, 0,
TranslateAnimation.ABSOLUTE, yTranslate);
bounceAnimation.setDuration(BOUNCE_ANIMATION_DURATION);
bounceAnimation.setFillEnabled(true);
bounceAnimation.setFillAfter(false);
bounceAnimation.setFillBefore(true);
bounceAnimation.setInterpolator(new OvershootInterpolator(BOUNCE_OVERSHOOT_TENSION));
bounceAnimation.setAnimationListener(new HeaderAnimationListener(yTranslate));
startAnimation(bounceAnimation);
}
private void resetHeader(){
if(getFirstVisiblePosition() > 0){
setHeaderPadding(-header.getHeight());
setState(State.PULL_TO_REFRESH);
return;
}
if(getAnimation() != null && !getAnimation().hasEnded()){
bounceBackHeader = true;
}else{
bounceBackHeader();
}
}
private void setUiRefreshing(){
spinner.setVisibility(View.VISIBLE);
image.clearAnimation();
image.setVisibility(View.INVISIBLE);
text.setText(refreshingText);
}
private void setState(State state){
this.state = state;
switch(state){
case PULL_TO_REFRESH:
spinner.setVisibility(View.INVISIBLE);
image.setVisibility(View.VISIBLE);
text.setText(pullToRefreshText);
if(showLastUpdatedText && lastUpdated != -1){
lastUpdatedTextView.setVisibility(View.VISIBLE);
lastUpdatedTextView.setText(String.format(lastUpdatedText, lastUpdatedDateFormat.format(new Date(lastUpdated))));
}
break;
case RELEASE_TO_REFRESH:
spinner.setVisibility(View.INVISIBLE);
image.setVisibility(View.VISIBLE);
text.setText(releaseToRefreshText);
break;
case REFRESHING:
setUiRefreshing();
lastUpdated = System.currentTimeMillis();
if(onRefreshListener == null){
setState(State.PULL_TO_REFRESH);
}else{
onRefreshListener.onRefresh();
}
break;
}
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt){
super.onScrollChanged(l, t, oldl, oldt);
if(!hasResetHeader){
if(measuredHeaderHeight > 0 && state != State.REFRESHING){
setHeaderPadding(-measuredHeaderHeight);
}
hasResetHeader = true;
}
}
private class HeaderAnimationListener implements AnimationListener{
private int height, translation;
private State stateAtAnimationStart;
public HeaderAnimationListener(int translation){
this.translation = translation;
}
public void onAnimationStart(Animation animation){
stateAtAnimationStart = state;
android.view.ViewGroup.LayoutParams lp = getLayoutParams();
height = lp.height;
lp.height = getHeight() - translation;
setLayoutParams(lp);
if(scrollbarEnabled){
setVerticalScrollBarEnabled(false);
}
}
// @Override
public void onAnimationEnd(Animation animation){
setHeaderPadding(stateAtAnimationStart == State.REFRESHING ? 0 : -measuredHeaderHeight - headerContainer.getTop());
setSelection(0);
android.view.ViewGroup.LayoutParams lp = getLayoutParams();
lp.height = height;
setLayoutParams(lp);
if(scrollbarEnabled){
setVerticalScrollBarEnabled(true);
}
if(bounceBackHeader){
bounceBackHeader = false;
postDelayed(new Runnable(){
// @Override
public void run(){
resetHeader();
}
}, BOUNCE_ANIMATION_DELAY);
}else if(stateAtAnimationStart != State.REFRESHING){
setState(State.PULL_TO_REFRESH);
}
}
// @Override
public void onAnimationRepeat(Animation animation){}
}
private class PTROnGlobalLayoutListener implements OnGlobalLayoutListener{
// @Override
public void onGlobalLayout(){
int initialHeaderHeight = header.getHeight();
if(initialHeaderHeight > 0){
measuredHeaderHeight = initialHeaderHeight;
if(measuredHeaderHeight > 0 && state != State.REFRESHING){
setHeaderPadding(-measuredHeaderHeight);
requestLayout();
}
}
getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
}
private class PTROnItemClickListener implements OnItemClickListener{
//
// @Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id){
hasResetHeader = false;
if(onItemClickListener != null && state == State.PULL_TO_REFRESH){
// Passing up onItemClick. Correct position with the number of header views
onItemClickListener.onItemClick(adapterView, view, position - getHeaderViewsCount(), id);
}
}
}
private class PTROnItemLongClickListener implements OnItemLongClickListener{
// @Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, int position, long id){
hasResetHeader = false;
if(onItemLongClickListener != null && state == State.PULL_TO_REFRESH){
// Passing up onItemLongClick. Correct position with the number of header views
return onItemLongClickListener.onItemLongClick(adapterView, view, position - getHeaderViewsCount(), id);
}
return false;
}
}
}
我真的不明白为什么它返回 1 而不是 0。