Java tutorial
/******************************************************************************* * 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.os.Build.VERSION; import android.os.Build.VERSION_CODES; import android.util.AttributeSet; import android.util.Log; import android.view.GestureDetector; import android.view.Gravity; import android.view.MotionEvent; import android.view.View; import android.widget.FrameLayout; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.Toast; import com.handmark.pulltorefresh.library.internal.AdapterOnSlideListener; import com.handmark.pulltorefresh.library.internal.EmptyViewMethodAccessor; import com.handmark.pulltorefresh.library.internal.LoadingLayout; import org.apache.http.conn.routing.RouteInfo; public class PullToRefreshListView extends PullToRefreshAdapterViewBase<ListView> { private LoadingLayout mHeaderLoadingView; private LoadingLayout mFooterLoadingView; private FrameLayout mLvFooterLoadingFrame; private boolean mListViewExtrasEnabled; public PullToRefreshListView(Context context) { super(context); } public PullToRefreshListView(Context context, AttributeSet attrs) { super(context, attrs); } public PullToRefreshListView(Context context, Mode mode) { super(context, mode); } public PullToRefreshListView(Context context, Mode mode, AnimationStyle style) { super(context, mode, style); } @Override public final Orientation getPullToRefreshScrollDirection() { return Orientation.VERTICAL; } @Override protected void onRefreshing(final boolean doScroll) { /** * If we're not showing the Refreshing view, or the list is empty, the * the header/footer views won't show so we use the normal method. */ ListAdapter adapter = mRefreshableView.getAdapter(); if (!mListViewExtrasEnabled || !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() - getFooterSize(); break; case PULL_FROM_START: default: origLoadingView = getHeaderLayout(); listViewLoadingView = mHeaderLoadingView; oppositeListViewLoadingView = mFooterLoadingView; selection = 0; scrollToY = getScrollY() + getHeaderSize(); break; } // Hide our original Loading View origLoadingView.reset(); origLoadingView.hideAllViews(); // Make sure the opposite end is hidden too oppositeListViewLoadingView.setVisibility(View.GONE); // Show the ListView Loading View and set it to refresh. listViewLoadingView.setVisibility(View.VISIBLE); listViewLoadingView.refreshing(); if (doScroll) { // We need to disable the automatic visibility changes for now disableLoadingLayoutVisibilityChanges(); // 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 protected void onReset() { /** * If the extras are not enabled, just call up to super and return. */ if (!mListViewExtrasEnabled) { super.onReset(); return; } 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 = getFooterSize(); scrollLvToEdge = Math.abs(mRefreshableView.getLastVisiblePosition() - selection) <= 1; break; case PULL_FROM_START: default: originalLoadingLayout = getHeaderLayout(); listViewLoadingLayout = mHeaderLoadingView; scrollToHeight = -getHeaderSize(); 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.showInvisibleViews(); // 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(); } @Override protected LoadingLayoutProxy createLoadingLayoutProxy(final boolean includeStart, final boolean includeEnd) { LoadingLayoutProxy proxy = super.createLoadingLayoutProxy(includeStart, includeEnd); if (mListViewExtrasEnabled) { final Mode mode = getMode(); if (includeStart && mode.showHeaderLoadingLayout()) { proxy.addLayout(mHeaderLoadingView); } if (includeEnd && mode.showFooterLoadingLayout()) { proxy.addLayout(mFooterLoadingView); } } return proxy; } 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); // Set it to this so it can be used in ListActivity/ListFragment lv.setId(android.R.id.list); return lv; } @Override protected void handleStyledAttributes(TypedArray a) { super.handleStyledAttributes(a); mListViewExtrasEnabled = a.getBoolean(R.styleable.PullToRefresh_ptrListViewExtrasEnabled, true); if (mListViewExtrasEnabled) { final FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.WRAP_CONTENT, Gravity.CENTER_HORIZONTAL); // Create Loading Views ready for use later FrameLayout frame = new FrameLayout(getContext()); mHeaderLoadingView = createLoadingLayout(getContext(), Mode.PULL_FROM_START, a); mHeaderLoadingView.setVisibility(View.GONE); frame.addView(mHeaderLoadingView, lp); mRefreshableView.addHeaderView(frame, null, false); mLvFooterLoadingFrame = new FrameLayout(getContext()); mFooterLoadingView = createLoadingLayout(getContext(), Mode.PULL_FROM_END, a); mFooterLoadingView.setVisibility(View.GONE); mLvFooterLoadingFrame.addView(mFooterLoadingView, lp); /** * If the value for Scrolling While Refreshing hasn't been * explicitly set via XML, enable Scrolling While Refreshing. */ if (!a.hasValue(R.styleable.PullToRefresh_ptrScrollingWhileRefreshingEnabled)) { setScrollingWhileRefreshingEnabled(true); } } } @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; } } @Override public void setAdapter(ListAdapter adapter) { // Add the Footer View at the last possible moment if (null != mLvFooterLoadingFrame && !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); } } }