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/* * Copyright 2014 The Android Open Source Project * * 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 android.support.app; import android.app.ListFragment; import android.content.Context; import android.os.Bundle; import android.support.v4.view.ViewCompat; import android.support.v4.widget.SwipeRefreshLayout; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ListView; /** * Subclass of {@link android.support.v4.app.ListFragment} which provides automatic support for * providing the 'swipe-to-refresh' UX gesture by wrapping the the content view in a * {@link android.support.v4.widget.SwipeRefreshLayout}. */ public class SwipeRefreshListFragment extends ListFragment { private SwipeRefreshLayout mSwipeRefreshLayout; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Create the list fragment's content view by calling the super method final View listFragmentView = super.onCreateView(inflater, container, savedInstanceState); // Now create a SwipeRefreshLayout to wrap the fragment's content view mSwipeRefreshLayout = new ListFragmentSwipeRefreshLayout(container.getContext()); // Add the list fragment's content view to the SwipeRefreshLayout, making sure that it fills // the SwipeRefreshLayout mSwipeRefreshLayout.addView(listFragmentView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT); // Make sure that the SwipeRefreshLayout will fill the fragment mSwipeRefreshLayout.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); // Now return the SwipeRefreshLayout as this fragment's content view return mSwipeRefreshLayout; } /** * Set the {@link android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener} to listen for * initiated refreshes. * * @see android.support.v4.widget.SwipeRefreshLayout#setOnRefreshListener(android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener) */ public void setOnRefreshListener(SwipeRefreshLayout.OnRefreshListener listener) { mSwipeRefreshLayout.setOnRefreshListener(listener); } /** * Returns whether the {@link android.support.v4.widget.SwipeRefreshLayout} is currently * refreshing or not. * * @see android.support.v4.widget.SwipeRefreshLayout#isRefreshing() */ public boolean isRefreshing() { return mSwipeRefreshLayout.isRefreshing(); } /** * Set whether the {@link android.support.v4.widget.SwipeRefreshLayout} should be displaying * that it is refreshing or not. * * @see android.support.v4.widget.SwipeRefreshLayout#setRefreshing(boolean) */ public void setRefreshing(boolean refreshing) { mSwipeRefreshLayout.setRefreshing(refreshing); } /** * Set the color scheme for the {@link android.support.v4.widget.SwipeRefreshLayout}. * * @see android.support.v4.widget.SwipeRefreshLayout#setColorScheme(int, int, int, int) */ public void setColorScheme(int colorRes1, int colorRes2, int colorRes3, int colorRes4) { mSwipeRefreshLayout.setColorScheme(colorRes1, colorRes2, colorRes3, colorRes4); } /** * @return the fragment's {@link android.support.v4.widget.SwipeRefreshLayout} widget. */ public SwipeRefreshLayout getSwipeRefreshLayout() { return mSwipeRefreshLayout; } /** * Sub-class of {@link android.support.v4.widget.SwipeRefreshLayout} for use in this * {@link android.support.v4.app.ListFragment}. The reason that this is needed is because * {@link android.support.v4.widget.SwipeRefreshLayout} only supports a single child, which it * expects to be the one which triggers refreshes. In our case the layout's child is the content * view returned from * {@link android.support.v4.app.ListFragment#onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)} * which is a {@link android.view.ViewGroup}. * * <p>To enable 'swipe-to-refresh' support via the {@link android.widget.ListView} we need to * override the default behavior and properly signal when a gesture is possible. This is done by * overriding {@link #canChildScrollUp()}. */ private class ListFragmentSwipeRefreshLayout extends SwipeRefreshLayout { public ListFragmentSwipeRefreshLayout(Context context) { super(context); } /** * As mentioned above, we need to override this method to properly signal when a * 'swipe-to-refresh' is possible. * * @return true if the {@link android.widget.ListView} is visible and can scroll up. */ @Override public boolean canChildScrollUp() { final ListView listView = getListView(); if (listView.getVisibility() == View.VISIBLE) { return canListViewScrollUp(listView); } else { return false; } } } // BEGIN_INCLUDE (check_list_can_scroll) /** * Utility method to check whether a {@link ListView} can scroll up from it's current position. * Handles platform version differences, providing backwards compatible functionality where * needed. */ private static boolean canListViewScrollUp(ListView listView) { if (android.os.Build.VERSION.SDK_INT >= 14) { // For ICS and above we can call canScrollVertically() to determine this return ViewCompat.canScrollVertically(listView, -1); } else { // Pre-ICS we need to manually check the first visible item and the child view's top // value return listView.getChildCount() > 0 && (listView.getFirstVisiblePosition() > 0 || listView.getChildAt(0).getTop() < listView.getPaddingTop()); } } // END_INCLUDE (check_list_can_scroll) }