Android中listView的底部拖拉翻页的实现 / iVAN

http://dengyin2000.iteye.com/blog/1187823

android-pulltorefresh组件。

https://github.com/johannilsson/android-pulltorefresh

在twitter微博中的，往下拉列表的话，顶部会自动load，而且有反弹的效果，非常cool。但是它的自动load顶部的内部，我现在需要拖拉listview到最后的时候load。这个组件不知道方向的选择，所以自己就动手改了下，实现从底部load。（今天发现新浪微博也实现了同样的功能。）。

Java代码

package com.markupartist.android.widget;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import android.content.Context;
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.ImageView;
import android.widget.RelativeLayout;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;
import com.markupartist.android.widget.pulltorefresh.R;
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 String TAG = "PullToRefreshListView";
private OnRefreshListener mOnRefreshListener;
/**
* Listener that will receive notifications every time the list scrolls.
*/
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 mRefreshOriginalBottomPadding;
private int mLastMotionY;
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
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();
mRefreshOriginalBottomPadding = mRefreshView.getPaddingBottom();
mRefreshState = TAP_TO_REFRESH;
// addHeaderView(mRefreshView);
addFooterView(mRefreshView);
super.setOnScrollListener(this);
measureView(mRefreshView);
mRefreshViewHeight = mRefreshView.getMeasuredHeight();
}
@Override
protected void onAttachedToWindow() {
//setSelection(1);
}
@Override
public void setAdapter(ListAdapter adapter) {
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(CharSequence lastUpdated) {
if (lastUpdated != null) {
mRefreshViewLastUpdated.setVisibility(View.VISIBLE);
mRefreshViewLastUpdated.setText(lastUpdated);
} else {
mRefreshViewLastUpdated.setVisibility(View.GONE);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY();
Log.i("PullToRefreshListView", "Height:" + getMeasuredHeight());
Log.i("PullToRefreshListView", "MotionEvent:" + event.getAction());
Log.i("PullToRefreshListView", "mRefreshState:" + mRefreshState);
Log.i("PullToRefreshListView", "FirstVisiblePosition:" + getFirstVisiblePosition());
Log.i("PullToRefreshListView", "LastVisiblePosition:" + getLastVisiblePosition());
Log.i("PullToRefreshListView", "ChildCount:" + getAdapter().getCount());
Log.i("PullToRefreshListView", "RefreshViewBottom:" + mRefreshView.getBottom());
Log.i("PullToRefreshListView", "RefreshViewTop:" + mRefreshView.getTop());
Log.i("PullToRefreshListView", "mRefreshViewHeight:" + mRefreshViewHeight);
Log.i("PullToRefreshListView", " ");
Log.i("PullToRefreshListView", " ");
Log.i("PullToRefreshListView", " ");
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
if (!isVerticalScrollBarEnabled()) {
setVerticalScrollBarEnabled(true);
}
if (getLastVisiblePosition() == getAdapter().getCount() - 1
&& mRefreshState != REFRESHING) {
if ((
mRefreshView.getTop() <= getMeasuredHeight() - mRefreshViewHeight)
&& mRefreshState == RELEASE_TO_REFRESH) {
// Log.i("PullToRefreshListView", "Fire...");
// Log.i("PullToRefreshListView", " ");
// Log.i("PullToRefreshListView", " ");
// Log.i("PullToRefreshListView", " ");
// Initiate the refresh
mRefreshState = REFRESHING;
prepareForRefresh();
onRefresh();
} else if (
mRefreshView.getTop() > getMeasuredHeight() - mRefreshViewHeight) {
// Abort refresh and scroll down below the refresh view
resetHeader();
//setSelection(1);
// Log.v("PPMacbook", "pi:" + (getSelectedItemPosition() - 1));
// setSelectionAfterHeaderView();
// setSelection(getSelectedItemPosition() - 1);
// System.out.println("PPMacbook:" + (getFirstVisiblePosition() - 1));
setSelection((getFirstVisiblePosition() - 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);
}
// Log.i("PullToRefreshListView", "historySize:" + historySize);
// Log.i("PullToRefreshListView", "pointerCount:" + pointerCount);
// Log.i("PullToRefreshListView", " ");
// Log.i("PullToRefreshListView", " ");
// Log.i("PullToRefreshListView", " ");
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(),
mRefreshView.getPaddingTop(),
mRefreshView.getPaddingRight(),
topPadding);
}
}
}
}
/**
* Sets the header padding back to original size.
*/
private void resetHeaderPadding() {
mRefreshView.setPadding(
mRefreshView.getPaddingLeft(),
mRefreshView.getPaddingTop(),
mRefreshView.getPaddingRight(),
mRefreshOriginalBottomPadding);
}
/**
* Resets the header to the original state.
*/
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);
}
}
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);
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// Log.i("PullToRefreshListView", "firstVisibleItem:" + firstVisibleItem);
// Log.i("PullToRefreshListView", "visibleItemCount:" + visibleItemCount);
// Log.i("PullToRefreshListView", "totalItemCount:" + totalItemCount);
// Log.i("PullToRefreshListView", "");
// Log.i("PullToRefreshListView", "");
// Log.i("PullToRefreshListView", "");
// 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 + visibleItemCount == totalItemCount) {
mRefreshViewImage.setVisibility(View.VISIBLE);
if ((
mRefreshView.getTop() <= getMeasuredHeight() - mRefreshViewHeight)
&& mRefreshState != RELEASE_TO_REFRESH) {
mRefreshViewText.setText(R.string.pull_to_refresh_release_label);
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mFlipAnimation);
mRefreshState = RELEASE_TO_REFRESH;
} else if (
mRefreshView.getTop() >getMeasuredHeight() - 20 - mRefreshViewHeight
&& mRefreshState != PULL_TO_REFRESH) {
mRefreshViewText.setText(R.string.pull_to_refresh_pull_label);
if (mRefreshState != TAP_TO_REFRESH) {
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mReverseFlipAnimation);
}
mRefreshState = PULL_TO_REFRESH;
}
} else {
mRefreshViewImage.setVisibility(View.GONE);
resetHeader();
}
} else if (mCurrentScrollState == SCROLL_STATE_FLING
&& firstVisibleItem + visibleItemCount == totalItemCount
&& mRefreshState != REFRESHING) {
//setSelection(1);
// Log.i("PullToRefreshListView", "Selection:" + (totalItemCount - visibleItemCount));
//// setSelection(getSelectedItemPosition() - 2);
//
setSelection((getFirstVisiblePosition() - 1));
}
if (mOnScrollListener != null) {
mOnScrollListener.onScroll(view, firstVisibleItem,
visibleItemCount, totalItemCount);
}
}
@Override
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() {
Log.d(TAG, "onRefresh");
if (mOnRefreshListener != null) {
mOnRefreshListener.onRefresh();
}
}
/**
* Resets the list to a normal state after a refresh.
* @param lastUpdated Last updated at.
*/
public void onRefreshComplete(CharSequence lastUpdated) {
setLastUpdated(lastUpdated);
onRefreshComplete();
}
/**
* Resets the list to a normal state after a refresh.
*/
public void onRefreshComplete() {
Log.d(TAG, "onRefreshComplete");
resetHeader();
// If refresh view is visible when loading completes, scroll down to
// the next item.
if (mRefreshView.getBottom() > 0) {
invalidateViews();
//setSelection(1);
}
}
/**
* Invoked when the refresh view is clicked on. This is mainly used when
* there's only a few items in the list and it's not possible to drag the
* list.
*/
private class OnClickRefreshListener implements OnClickListener {
@Override
public void onClick(View v) {
if (mRefreshState != REFRESHING) {
prepareForRefresh();
onRefresh();
}
}
}
/**
* Interface definition for a callback to be invoked when list should be
* refreshed.
*/
public interface OnRefreshListener {
/**
* Called when the list should be refreshed.
* <p>
* A call to {@link PullToRefreshListView #onRefreshComplete()} is
* expected to indicate that the refresh has completed.
*/
public void onRefresh();
}
}

pulltorefresh.zip (59.7
KB)

时间： 2024-09-13 17:51:47

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