PinnedHeaderListView ListView固定头部

package za.co.immedia.pinnedheaderlistview; import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.widget.*; import android.widget.AbsListView.OnScrollListener; public class PinnedHeaderListView extends ListView implements OnScrollListener { private OnScrollListener mOnScrollListener; public static interface PinnedSectionedHeaderAdapter { public boolean isSectionHeader(int position); public int getSectionForPosition(int position); public View getSectionHeaderView(int section, View convertView, ViewGroup parent); public int getSectionHeaderViewType(int section); public int getCount(); } private PinnedSectionedHeaderAdapter mAdapter; private View mCurrentHeader; private int mCurrentHeaderViewType = 0; private float mHeaderOffset; private boolean mShouldPin = true; private int mCurrentSection = 0; private int mWidthMode; private int mHeightMode; public PinnedHeaderListView(Context context) { super(context); super.setOnScrollListener(this); } public PinnedHeaderListView(Context context, AttributeSet attrs) { super(context, attrs); super.setOnScrollListener(this); } public PinnedHeaderListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); super.setOnScrollListener(this); } public void setPinHeaders(boolean shouldPin) { mShouldPin = shouldPin; } @Override public void setAdapter(ListAdapter adapter) { mCurrentHeader = null; mAdapter = (PinnedSectionedHeaderAdapter) adapter; super.setAdapter(adapter); } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { if (mOnScrollListener != null) { mOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount); } if (mAdapter == null || mAdapter.getCount() == 0 || !mShouldPin || (firstVisibleItem < getHeaderViewsCount())) { mCurrentHeader = null; mHeaderOffset = 0.0f; for (int i = firstVisibleItem; i < firstVisibleItem + visibleItemCount; i++) { View header = getChildAt(i); if (header != null) { header.setVisibility(VISIBLE); } } return; } firstVisibleItem -= getHeaderViewsCount(); int section = mAdapter.getSectionForPosition(firstVisibleItem); int viewType = mAdapter.getSectionHeaderViewType(section); mCurrentHeader = getSectionHeaderView(section, mCurrentHeaderViewType != viewType ? null : mCurrentHeader); ensurePinnedHeaderLayout(mCurrentHeader); mCurrentHeaderViewType = viewType; mHeaderOffset = 0.0f; for (int i = firstVisibleItem; i < firstVisibleItem + visibleItemCount; i++) { if (mAdapter.isSectionHeader(i)) { View header = getChildAt(i - firstVisibleItem); float headerTop = header.getTop(); float pinnedHeaderHeight = mCurrentHeader.getMeasuredHeight(); header.setVisibility(VISIBLE); if (pinnedHeaderHeight >= headerTop && headerTop > 0) { mHeaderOffset = headerTop - header.getHeight(); } else if (headerTop <= 0) { header.setVisibility(INVISIBLE); } } } invalidate(); } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { if (mOnScrollListener != null) { mOnScrollListener.onScrollStateChanged(view, scrollState); } } private View getSectionHeaderView(int section, View oldView) { boolean shouldLayout = section != mCurrentSection || oldView == null; View view = mAdapter.getSectionHeaderView(section, oldView, this); if (shouldLayout) { // a new section, thus a new header. We should lay it out again ensurePinnedHeaderLayout(view); mCurrentSection = section; } return view; } private void ensurePinnedHeaderLayout(View header) { if (header.isLayoutRequested()) { int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), mWidthMode); int heightSpec; ViewGroup.LayoutParams layoutParams = header.getLayoutParams(); if (layoutParams != null && layoutParams.height > 0) { heightSpec = MeasureSpec.makeMeasureSpec(layoutParams.height, MeasureSpec.EXACTLY); } else { heightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } header.measure(widthSpec, heightSpec); header.layout(0, 0, header.getMeasuredWidth(), header.getMeasuredHeight()); } } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); if (mAdapter == null || !mShouldPin || mCurrentHeader == null) return; int saveCount = canvas.save(); canvas.translate(0, mHeaderOffset); canvas.clipRect(0, 0, getWidth(), mCurrentHeader.getMeasuredHeight()); // needed // for // < // HONEYCOMB mCurrentHeader.draw(canvas); canvas.restoreToCount(saveCount); } @Override public void setOnScrollListener(OnScrollListener l) { mOnScrollListener = l; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); mWidthMode = MeasureSpec.getMode(widthMeasureSpec); mHeightMode = MeasureSpec.getMode(heightMeasureSpec); } public void setOnItemClickListener(PinnedHeaderListView.OnItemClickListener listener) { super.setOnItemClickListener(listener); } public static abstract class OnItemClickListener implements AdapterView.OnItemClickListener { @Override public void onItemClick(AdapterView<?> adapterView, View view, int rawPosition, long id) { SectionedBaseAdapter adapter; if (adapterView.getAdapter().getClass().equals(HeaderViewListAdapter.class)) { HeaderViewListAdapter wrapperAdapter = (HeaderViewListAdapter) adapterView.getAdapter(); adapter = (SectionedBaseAdapter) wrapperAdapter.getWrappedAdapter(); } else { adapter = (SectionedBaseAdapter) adapterView.getAdapter(); } int section = adapter.getSectionForPosition(rawPosition); int position = adapter.getPositionInSectionForPosition(rawPosition); if (position == -1) { onSectionClick(adapterView, view, section, id); } else { onItemClick(adapterView, view, section, position, id); } } public abstract void onItemClick(AdapterView<?> adapterView, View view, int section, int position, long id); public abstract void onSectionClick(AdapterView<?> adapterView, View view, int section, long id); } }