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@shanyou
Created June 5, 2013 03:26
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AmazingListView.java
package com.foound.widget;
import android.content.*;
import android.graphics.*;
import android.util.*;
import android.view.*;
import android.widget.*;
import com.foound.widget.AmazingAdapter.HasMorePagesListener;
/**
* A ListView that maintains a header pinned at the top of the list. The
* pinned header can be pushed up and dissolved as needed.
*
* It also supports pagination by setting a custom view as the loading
* indicator.
*/
public class AmazingListView extends ListView implements HasMorePagesListener {
public static final String TAG = AmazingListView.class.getSimpleName();
View listFooter;
boolean footerViewAttached = false;
private View mHeaderView;
private boolean mHeaderViewVisible;
private int mHeaderViewWidth;
private int mHeaderViewHeight;
private AmazingAdapter adapter;
public void setPinnedHeaderView(View view) {
mHeaderView = view;
// Disable vertical fading when the pinned header is present
// TODO change ListView to allow separate measures for top and bottom fading edge;
// in this particular case we would like to disable the top, but not the bottom edge.
if (mHeaderView != null) {
setFadingEdgeLength(0);
}
requestLayout();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mHeaderView != null) {
measureChild(mHeaderView, widthMeasureSpec, heightMeasureSpec);
mHeaderViewWidth = mHeaderView.getMeasuredWidth();
mHeaderViewHeight = mHeaderView.getMeasuredHeight();
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
if (mHeaderView != null) {
mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
configureHeaderView(getFirstVisiblePosition());
}
}
public void configureHeaderView(int position) {
if (mHeaderView == null) {
return;
}
int state = adapter.getPinnedHeaderState(position);
switch (state) {
case AmazingAdapter.PINNED_HEADER_GONE: {
mHeaderViewVisible = false;
break;
}
case AmazingAdapter.PINNED_HEADER_VISIBLE: {
adapter.configurePinnedHeader(mHeaderView, position, 255);
if (mHeaderView.getTop() != 0) {
mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
}
mHeaderViewVisible = true;
break;
}
case AmazingAdapter.PINNED_HEADER_PUSHED_UP: {
View firstView = getChildAt(0);
if (firstView != null) {
int bottom = firstView.getBottom();
int headerHeight = mHeaderView.getHeight();
int y;
int alpha;
if (bottom < headerHeight) {
y = (bottom - headerHeight);
alpha = 255 * (headerHeight + y) / headerHeight;
} else {
y = 0;
alpha = 255;
}
adapter.configurePinnedHeader(mHeaderView, position, alpha);
if (mHeaderView.getTop() != y) {
mHeaderView.layout(0, y, mHeaderViewWidth, mHeaderViewHeight + y);
}
mHeaderViewVisible = true;
}
break;
}
}
}
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
if (mHeaderViewVisible) {
drawChild(canvas, mHeaderView, getDrawingTime());
}
}
public AmazingListView(Context context) {
super(context);
}
public AmazingListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public AmazingListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public void setLoadingView(View listFooter) {
this.listFooter = listFooter;
}
public View getLoadingView() {
return listFooter;
}
@Override
public void setAdapter(ListAdapter adapter) {
if (!(adapter instanceof AmazingAdapter)) {
throw new IllegalArgumentException(AmazingListView.class.getSimpleName() + " must use adapter of type " + AmazingAdapter.class.getSimpleName());
}
// previous adapter
if (this.adapter != null) {
this.adapter.setHasMorePagesListener(null);
this.setOnScrollListener(null);
}
this.adapter = (AmazingAdapter) adapter;
((AmazingAdapter)adapter).setHasMorePagesListener(this);
this.setOnScrollListener((AmazingAdapter) adapter);
View dummy = new View(getContext());
super.addFooterView(dummy);
super.setAdapter(adapter);
super.removeFooterView(dummy);
}
@Override
public AmazingAdapter getAdapter() {
return adapter;
}
@Override
public void noMorePages() {
if (listFooter != null) {
this.removeFooterView(listFooter);
}
footerViewAttached = false;
}
@Override
public void mayHaveMorePages() {
if (! footerViewAttached && listFooter != null) {
this.addFooterView(listFooter);
footerViewAttached = true;
}
}
public boolean isLoadingViewVisible() {
return footerViewAttached;
}
}
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