PullToRefreshListView.java

/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.handmark.pulltorefresh.library;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.util.AttributeSet;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ListAdapter;
import android.widget.ListView;

import com.handmark.pulltorefresh.library.internal.EmptyViewMethodAccessor;
import com.handmark.pulltorefresh.library.internal.LoadingLayout;

public class PullToRefreshListView extends PullToRefreshAdapterViewBase<ListView> {

	private LoadingLayout mHeaderLoadingView;
	private LoadingLayout mFooterLoadingView;

	private FrameLayout mLvFooterLoadingFrame;

	public PullToRefreshListView(Context context) {
		super(context);
		setDisableScrollingWhileRefreshing(false);
	}

	public PullToRefreshListView(Context context, AttributeSet attrs) {
		super(context, attrs);
		setDisableScrollingWhileRefreshing(false);
	}

	public PullToRefreshListView(Context context, Mode mode) {
		super(context, mode);
		setDisableScrollingWhileRefreshing(false);
	}

	@Override
	public ContextMenuInfo getContextMenuInfo() {
		return ((InternalListView) getRefreshableView()).getContextMenuInfo();
	}

	@Override
	public void setLastUpdatedLabel(CharSequence label) {
		super.setLastUpdatedLabel(label);

		if (null != mHeaderLoadingView) {
			mHeaderLoadingView.setSubHeaderText(label);
		}
		if (null != mFooterLoadingView) {
			mFooterLoadingView.setSubHeaderText(label);
		}
	}

	@Override
	public void setLoadingDrawable(Drawable drawable, Mode mode) {
		super.setLoadingDrawable(drawable, mode);

		if (null != mHeaderLoadingView && mode.showHeaderLoadingLayout()) {
			mHeaderLoadingView.setLoadingDrawable(drawable);
		}
		if (null != mFooterLoadingView && mode.showFooterLoadingLayout()) {
			mFooterLoadingView.setLoadingDrawable(drawable);
		}
	}

	public void setPullLabel(CharSequence pullLabel, Mode mode) {
		super.setPullLabel(pullLabel, mode);

		if (null != mHeaderLoadingView && mode.showHeaderLoadingLayout()) {
			mHeaderLoadingView.setPullLabel(pullLabel);
		}
		if (null != mFooterLoadingView && mode.showFooterLoadingLayout()) {
			mFooterLoadingView.setPullLabel(pullLabel);
		}
	}

	public void setRefreshingLabel(CharSequence refreshingLabel, Mode mode) {
		super.setRefreshingLabel(refreshingLabel, mode);

		if (null != mHeaderLoadingView && mode.showHeaderLoadingLayout()) {
			mHeaderLoadingView.setRefreshingLabel(refreshingLabel);
		}
		if (null != mFooterLoadingView && mode.showFooterLoadingLayout()) {
			mFooterLoadingView.setRefreshingLabel(refreshingLabel);
		}
	}

	public void setReleaseLabel(CharSequence releaseLabel, Mode mode) {
		super.setReleaseLabel(releaseLabel, mode);

		if (null != mHeaderLoadingView && mode.showHeaderLoadingLayout()) {
			mHeaderLoadingView.setReleaseLabel(releaseLabel);
		}
		if (null != mFooterLoadingView && mode.showFooterLoadingLayout()) {
			mFooterLoadingView.setReleaseLabel(releaseLabel);
		}
	}

	@Override
	public final int getPullToRefreshScrollDirection() {
		return VERTICAL_SCROLL;
	}

	@Override
	void onRefreshing(final boolean doScroll) {

		// If we're not showing the Refreshing view, or the list is empty, then
		// the header/footer views won't show so we use the
		// normal method
		ListAdapter adapter = mRefreshableView.getAdapter();
		if (!getShowViewWhileRefreshing() || null == adapter || adapter.isEmpty()) {
			super.onRefreshing(doScroll);
			return;
		}

		super.onRefreshing(false);

		final LoadingLayout origLoadingView, listViewLoadingView, oppositeListViewLoadingView;
		final int selection, scrollToY;

		switch (getCurrentMode()) {
			case MANUAL_REFRESH_ONLY:
			case PULL_FROM_END:
				origLoadingView = getFooterLayout();
				listViewLoadingView = mFooterLoadingView;
				oppositeListViewLoadingView = mHeaderLoadingView;
				selection = mRefreshableView.getCount() - 1;
				scrollToY = getScrollY() - getFooterHeight();
				break;
			case PULL_FROM_START:
			default:
				origLoadingView = getHeaderLayout();
				listViewLoadingView = mHeaderLoadingView;
				oppositeListViewLoadingView = mFooterLoadingView;
				selection = 0;
				scrollToY = getScrollY() + getHeaderHeight();
				break;
		}

		// Hide our original Loading View
		origLoadingView.setVisibility(View.INVISIBLE);
		
		// Make sure the opposite end is hidden too
		oppositeListViewLoadingView.setVisibility(View.GONE);

		// Show the ListView Loading View and set it to refresh. If it has a 0
		// height, then we need to set it to WRAP_CONTENT
		if (listViewLoadingView.getHeight() == 0) {
			ViewGroup.LayoutParams lp = listViewLoadingView.getLayoutParams();
			lp.height = ViewGroup.LayoutParams.WRAP_CONTENT;
			listViewLoadingView.setLayoutParams(lp);
		}
		listViewLoadingView.setVisibility(View.VISIBLE);
		
		listViewLoadingView.refreshing();

		if (doScroll) {
			// We scroll slightly so that the ListView's header/footer is at the
			// same Y position as our normal header/footer
			setHeaderScroll(scrollToY);

			// Make sure the ListView is scrolled to show the loading
			// header/footer
			mRefreshableView.setSelection(selection);

			// Smooth scroll as normal
			smoothScrollTo(0);
		}
	}

	@Override
	void onReset() {
		final LoadingLayout originalLoadingLayout, listViewLoadingLayout;
		final int scrollToHeight, selection;
		final boolean scrollLvToEdge;

		switch (getCurrentMode()) {
			case MANUAL_REFRESH_ONLY:
			case PULL_FROM_END:
				originalLoadingLayout = getFooterLayout();
				listViewLoadingLayout = mFooterLoadingView;
				selection = mRefreshableView.getCount() - 1;
				scrollToHeight = getFooterHeight();
				scrollLvToEdge = Math.abs(mRefreshableView.getLastVisiblePosition() - selection) <= 1;
				break;
			case PULL_FROM_START:
			default:
				originalLoadingLayout = getHeaderLayout();
				listViewLoadingLayout = mHeaderLoadingView;
				scrollToHeight = -getHeaderHeight();
				selection = 0;
				scrollLvToEdge = Math.abs(mRefreshableView.getFirstVisiblePosition() - selection) <= 1;
				break;
		}

		// If the ListView header loading layout is showing, then we need to
		// flip so that the original one is showing instead
		if (listViewLoadingLayout.getVisibility() == View.VISIBLE) {

			// Set our Original View to Visible
			originalLoadingLayout.setVisibility(View.VISIBLE);

			// Hide the ListView Header/Footer
			listViewLoadingLayout.setVisibility(View.GONE);

			/**
			 * Scroll so the View is at the same Y as the ListView
			 * header/footer, but only scroll if: we've pulled to refresh, it's
			 * positioned correctly
			 */
			if (scrollLvToEdge && getState() != State.MANUAL_REFRESHING) {
				mRefreshableView.setSelection(selection);
				setHeaderScroll(scrollToHeight);
			}
		}

		// Finally, call up to super
		super.onReset();
	}

	protected ListView createListView(Context context, AttributeSet attrs) {
		final ListView lv;
		if (VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD) {
			lv = new InternalListViewSDK9(context, attrs);
		} else {
			lv = new InternalListView(context, attrs);
		}
		return lv;
	}

	@Override
	protected ListView createRefreshableView(Context context, AttributeSet attrs) {
		ListView lv = createListView(context, attrs);

		// Get Styles from attrs
		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PullToRefresh);

		// We use a 0 height (instead of View.GONE) for now so that it's still
		// measured and laid out
		final FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, 0,
				Gravity.CENTER_HORIZONTAL);

		// Create Loading Views ready for use later
		FrameLayout frame = new FrameLayout(context);
		mHeaderLoadingView = createLoadingLayout(context, Mode.PULL_FROM_START, a);
		frame.addView(mHeaderLoadingView, lp);
		lv.addHeaderView(frame, null, false);

		mLvFooterLoadingFrame = new FrameLayout(context);
		mFooterLoadingView = createLoadingLayout(context, Mode.PULL_FROM_END, a);
		mLvFooterLoadingFrame.addView(mFooterLoadingView, lp);

		a.recycle();

		// Set it to this so it can be used in ListActivity/ListFragment
		lv.setId(android.R.id.list);
		return lv;
	}

	@TargetApi(9)
	final class InternalListViewSDK9 extends InternalListView {

		public InternalListViewSDK9(Context context, AttributeSet attrs) {
			super(context, attrs);
		}

		@Override
		protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX,
				int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {

			final boolean returnValue = super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX,
					scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);

			// Does all of the hard work...
			OverscrollHelper.overScrollBy(PullToRefreshListView.this, deltaX, scrollX, deltaY, scrollY, isTouchEvent);

			return returnValue;
		}
	}

	protected class InternalListView extends ListView implements EmptyViewMethodAccessor {

		private boolean mAddedLvFooter = false;

		public InternalListView(Context context, AttributeSet attrs) {
			super(context, attrs);
		}

		@Override
		protected void dispatchDraw(Canvas canvas) {
			/**
			 * This is a bit hacky, but Samsung's ListView has got a bug in it
			 * when using Header/Footer Views and the list is empty. This masks
			 * the issue so that it doesn't cause an FC. See Issue #66.
			 */
			try {
				super.dispatchDraw(canvas);
			} catch (IndexOutOfBoundsException e) {
				e.printStackTrace();
			}
		}

		@Override
		public boolean dispatchTouchEvent(MotionEvent ev) {
			/**
			 * This is a bit hacky, but Samsung's ListView has got a bug in it
			 * when using Header/Footer Views and the list is empty. This masks
			 * the issue so that it doesn't cause an FC. See Issue #66.
			 */
			try {
				return super.dispatchTouchEvent(ev);
			} catch (IndexOutOfBoundsException e) {
				e.printStackTrace();
				return false;
			}
		}

		public ContextMenuInfo getContextMenuInfo() {
			return super.getContextMenuInfo();
		}

		@Override
		public void setAdapter(ListAdapter adapter) {
			// Add the Footer View at the last possible moment
			if (!mAddedLvFooter) {
				addFooterView(mLvFooterLoadingFrame, null, false);
				mAddedLvFooter = true;
			}

			super.setAdapter(adapter);
		}

		@Override
		public void setEmptyView(View emptyView) {
			PullToRefreshListView.this.setEmptyView(emptyView);
		}

		@Override
		public void setEmptyViewInternal(View emptyView) {
			super.setEmptyView(emptyView);
		}

	}

}