1/*
2 * Copyright 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package eu.siacs.conversations.ui.widget;
18
19import android.content.Context;
20import android.os.Bundle;
21import android.view.LayoutInflater;
22import android.view.View;
23import android.view.ViewGroup;
24import android.widget.ListView;
25
26import androidx.fragment.app.ListFragment;
27import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
28
29import eu.siacs.conversations.ui.util.StyledAttributes;
30
31/**
32 * Subclass of {@link androidx.fragment.app.ListFragment} which provides automatic support for
33 * providing the 'swipe-to-refresh' UX gesture by wrapping the the content view in a
34 * {@link androidx.swiperefreshlayout.widget.SwipeRefreshLayout}.
35 */
36public class SwipeRefreshListFragment extends ListFragment {
37
38 private boolean enabled = false;
39 private boolean refreshing = false;
40
41 private SwipeRefreshLayout.OnRefreshListener onRefreshListener;
42
43 private SwipeRefreshLayout mSwipeRefreshLayout;
44
45 @Override
46 public View onCreateView(LayoutInflater inflater, ViewGroup container,
47 Bundle savedInstanceState) {
48
49 // Create the list fragment's content view by calling the super method
50 final View listFragmentView = super.onCreateView(inflater, container, savedInstanceState);
51
52 // Now create a SwipeRefreshLayout to wrap the fragment's content view
53 mSwipeRefreshLayout = new ListFragmentSwipeRefreshLayout(container.getContext());
54 mSwipeRefreshLayout.setEnabled(enabled);
55 mSwipeRefreshLayout.setRefreshing(refreshing);
56
57 final Context context = getActivity();
58 if (context != null) {
59 mSwipeRefreshLayout.setColorSchemeColors(StyledAttributes.getColor(context, androidx.appcompat.R.attr.colorAccent));
60 }
61
62 if (onRefreshListener != null) {
63 mSwipeRefreshLayout.setOnRefreshListener(onRefreshListener);
64 }
65
66 // Add the list fragment's content view to the SwipeRefreshLayout, making sure that it fills
67 // the SwipeRefreshLayout
68 mSwipeRefreshLayout.addView(listFragmentView,
69 ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
70
71 // Make sure that the SwipeRefreshLayout will fill the fragment
72 mSwipeRefreshLayout.setLayoutParams(
73 new ViewGroup.LayoutParams(
74 ViewGroup.LayoutParams.MATCH_PARENT,
75 ViewGroup.LayoutParams.MATCH_PARENT));
76
77 // Now return the SwipeRefreshLayout as this fragment's content view
78 return mSwipeRefreshLayout;
79 }
80
81 /**
82 * Set the {@link androidx.core.widget.SwipeRefreshLayout.OnRefreshListener} to listen for
83 * initiated refreshes.
84 *
85 * @see androidx.core.widget.SwipeRefreshLayout#setOnRefreshListener(androidx.core.widget.SwipeRefreshLayout.OnRefreshListener)
86 */
87 public void setOnRefreshListener(SwipeRefreshLayout.OnRefreshListener listener) {
88 onRefreshListener = listener;
89 enabled = true;
90 if (mSwipeRefreshLayout != null) {
91 mSwipeRefreshLayout.setEnabled(true);
92 mSwipeRefreshLayout.setOnRefreshListener(listener);
93 }
94 }
95
96 /**
97 * Set whether the {@link androidx.core.widget.SwipeRefreshLayout} should be displaying
98 * that it is refreshing or not.
99 *
100 * @see androidx.core.widget.SwipeRefreshLayout#setRefreshing(boolean)
101 */
102 public void setRefreshing(boolean refreshing) {
103 this.refreshing = refreshing;
104 if (mSwipeRefreshLayout != null) {
105 mSwipeRefreshLayout.setRefreshing(refreshing);
106 }
107 }
108
109
110 /**
111 * Sub-class of {@link androidx.core.widget.SwipeRefreshLayout} for use in this
112 * {@link androidx.core.app.ListFragment}. The reason that this is needed is because
113 * {@link androidx.core.widget.SwipeRefreshLayout} only supports a single child, which it
114 * expects to be the one which triggers refreshes. In our case the layout's child is the content
115 * view returned from
116 * {@link androidx.core.app.ListFragment#onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)}
117 * which is a {@link android.view.ViewGroup}.
118 *
119 * <p>To enable 'swipe-to-refresh' support via the {@link android.widget.ListView} we need to
120 * override the default behavior and properly signal when a gesture is possible. This is done by
121 * overriding {@link #canChildScrollUp()}.
122 */
123 private class ListFragmentSwipeRefreshLayout extends SwipeRefreshLayout {
124
125 public ListFragmentSwipeRefreshLayout(Context context) {
126 super(context);
127 }
128
129 /**
130 * As mentioned above, we need to override this method to properly signal when a
131 * 'swipe-to-refresh' is possible.
132 *
133 * @return true if the {@link android.widget.ListView} is visible and can scroll up.
134 */
135 @Override
136 public boolean canChildScrollUp() {
137 final ListView listView = getListView();
138 if (listView.getVisibility() == View.VISIBLE) {
139 return listView.canScrollVertically(-1);
140 } else {
141 return false;
142 }
143 }
144
145 }
146
147}