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| 1 | +package com.parse.ui.widget.sample; |
| 2 | + |
| 3 | +import android.os.Bundle; |
| 4 | +import android.support.v4.widget.SwipeRefreshLayout; |
| 5 | +import android.support.v7.app.AppCompatActivity; |
| 6 | +import android.support.v7.widget.LinearLayoutManager; |
| 7 | +import android.support.v7.widget.RecyclerView; |
| 8 | +import android.view.LayoutInflater; |
| 9 | +import android.view.View; |
| 10 | +import android.view.ViewGroup; |
| 11 | +import android.widget.ProgressBar; |
| 12 | +import android.widget.TextView; |
| 13 | + |
| 14 | +import com.parse.ParseObject; |
| 15 | +import com.parse.ParseQuery; |
| 16 | +import com.parse.widget.util.ParseQueryPager; |
| 17 | + |
| 18 | +import java.util.List; |
| 19 | + |
| 20 | +import bolts.CancellationTokenSource; |
| 21 | +import bolts.Continuation; |
| 22 | +import bolts.Task; |
| 23 | + |
| 24 | +public class RecyclerActivity extends AppCompatActivity { |
| 25 | + |
| 26 | + private SwipeRefreshLayout refreshLayout; |
| 27 | + |
| 28 | + private MyAdapter<ParseObject> adapter; |
| 29 | + |
| 30 | + @Override |
| 31 | + protected void onCreate(Bundle savedInstanceState) { |
| 32 | + super.onCreate(savedInstanceState); |
| 33 | + setContentView(R.layout.activity_recycler); |
| 34 | + |
| 35 | + RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler); |
| 36 | + |
| 37 | + RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this); |
| 38 | + recyclerView.setLayoutManager(layoutManager); |
| 39 | + |
| 40 | + adapter = new MyAdapter<>(createPager()); |
| 41 | + recyclerView.setAdapter(adapter); |
| 42 | + |
| 43 | + refreshLayout = (SwipeRefreshLayout) findViewById(R.id.refresh); |
| 44 | + refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() { |
| 45 | + @Override |
| 46 | + public void onRefresh() { |
| 47 | + final ParseQueryPager<ParseObject> pager = createPager(); |
| 48 | + pager.loadNextPage().continueWith(new Continuation<List<ParseObject>, Void>() { |
| 49 | + @Override |
| 50 | + public Void then(Task<List<ParseObject>> task) throws Exception { |
| 51 | + refreshLayout.setRefreshing(false); |
| 52 | + |
| 53 | + if (task.isCancelled()) { |
| 54 | + return null; |
| 55 | + } |
| 56 | + |
| 57 | + if (task.isFaulted()) { |
| 58 | + return null; |
| 59 | + } |
| 60 | + |
| 61 | + adapter.swap(pager); |
| 62 | + adapter.notifyDataSetChanged(); |
| 63 | + return null; |
| 64 | + } |
| 65 | + }, Task.UI_THREAD_EXECUTOR); |
| 66 | + } |
| 67 | + }); |
| 68 | + } |
| 69 | + |
| 70 | + private ParseQueryPager<ParseObject> createPager() { |
| 71 | + ParseQuery<ParseObject> query = ParseQuery.getQuery("TestObject"); |
| 72 | + query.orderByAscending("name"); |
| 73 | + return new ParseQueryPager<>(query, 25); |
| 74 | + } |
| 75 | + |
| 76 | + public static class MyAdapter<T extends ParseObject> extends RecyclerView.Adapter<RecyclerView.ViewHolder> { |
| 77 | + |
| 78 | + private static final int TYPE_ITEM = 0; |
| 79 | + private static final int TYPE_NEXT = 1; |
| 80 | + |
| 81 | + private static class ItemViewHolder extends RecyclerView.ViewHolder { |
| 82 | + TextView textView; |
| 83 | + |
| 84 | + public ItemViewHolder(View itemView) { |
| 85 | + super(itemView); |
| 86 | + textView = (TextView) itemView; |
| 87 | + } |
| 88 | + } |
| 89 | + |
| 90 | + private static class NextViewHolder extends RecyclerView.ViewHolder { |
| 91 | + TextView textView; |
| 92 | + ProgressBar progressBar; |
| 93 | + |
| 94 | + public NextViewHolder(View itemView) { |
| 95 | + super(itemView); |
| 96 | + textView = (TextView) itemView.findViewById(android.R.id.text1); |
| 97 | + progressBar = (ProgressBar) itemView.findViewById(android.R.id.progress); |
| 98 | + } |
| 99 | + |
| 100 | + public void setLoading(boolean loading) { |
| 101 | + if (loading) { |
| 102 | + textView.setVisibility(View.INVISIBLE); |
| 103 | + progressBar.setVisibility(View.VISIBLE); |
| 104 | + progressBar.setIndeterminate(true); |
| 105 | + } else { |
| 106 | + textView.setVisibility(View.VISIBLE); |
| 107 | + progressBar.setVisibility(View.INVISIBLE); |
| 108 | + progressBar.setIndeterminate(false); |
| 109 | + } |
| 110 | + } |
| 111 | + } |
| 112 | + |
| 113 | + private final Object lock = new Object(); |
| 114 | + private ParseQueryPager<T> pager; |
| 115 | + private CancellationTokenSource cts; |
| 116 | + |
| 117 | + public MyAdapter(ParseQueryPager<T> pager) { |
| 118 | + swap(pager); |
| 119 | + } |
| 120 | + |
| 121 | + public ParseQueryPager<T> getPager() { |
| 122 | + synchronized (lock) { |
| 123 | + return pager; |
| 124 | + } |
| 125 | + } |
| 126 | + |
| 127 | + public void swap(ParseQueryPager<T> pager) { |
| 128 | + synchronized (lock) { |
| 129 | + if (cts != null) { |
| 130 | + cts.cancel(); |
| 131 | + } |
| 132 | + this.pager = pager; |
| 133 | + this.cts = new CancellationTokenSource(); |
| 134 | + } |
| 135 | + } |
| 136 | + |
| 137 | + private void loadNextPage() { |
| 138 | + final ParseQueryPager<T> pager; |
| 139 | + final CancellationTokenSource cts; |
| 140 | + |
| 141 | + synchronized (lock) { |
| 142 | + pager = this.pager; |
| 143 | + cts = this.cts; |
| 144 | + } |
| 145 | + |
| 146 | + final int oldSize = pager.getObjects().size(); |
| 147 | + |
| 148 | + // Uses Tasks, so it does not support CACHE_THEN_NETWORK. See ListActivity for a sample |
| 149 | + // with callbacks. |
| 150 | + pager.loadNextPage(cts.getToken()).continueWith(new Continuation<List<T>, Task<Void>>() { |
| 151 | + @Override |
| 152 | + public Task<Void> then(Task<List<T>> task) throws Exception { |
| 153 | + if (task.isCancelled()) { |
| 154 | + return null; |
| 155 | + } |
| 156 | + |
| 157 | + if (task.isFaulted()) { |
| 158 | + notifyDataSetChanged(); |
| 159 | + return null; |
| 160 | + } |
| 161 | + |
| 162 | + // Remove "Load more..." |
| 163 | + notifyItemRemoved(oldSize); |
| 164 | + |
| 165 | + // Insert results |
| 166 | + List<T> results = task.getResult(); |
| 167 | + if (results.size() > 0) { |
| 168 | + notifyItemRangeInserted(oldSize, results.size()); |
| 169 | + } |
| 170 | + |
| 171 | + if (pager.hasNextPage()) { |
| 172 | + // Add "Load more..." |
| 173 | + notifyItemInserted(pager.getObjects().size()); |
| 174 | + } |
| 175 | + return null; |
| 176 | + } |
| 177 | + }); |
| 178 | + notifyItemChanged(oldSize); |
| 179 | + } |
| 180 | + |
| 181 | + @Override |
| 182 | + public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { |
| 183 | + LayoutInflater inflater = LayoutInflater.from(parent.getContext()); |
| 184 | + switch (viewType) { |
| 185 | + case TYPE_ITEM: { |
| 186 | + View v = inflater.inflate(android.R.layout.simple_list_item_1, parent, false); |
| 187 | + return new ItemViewHolder(v); |
| 188 | + } |
| 189 | + case TYPE_NEXT: { |
| 190 | + View v = inflater.inflate(R.layout.load_more_list_item, parent, false); |
| 191 | + v.setOnClickListener(new View.OnClickListener() { |
| 192 | + @Override |
| 193 | + public void onClick(View v) { |
| 194 | + if (!getPager().isLoadingNextPage()) { |
| 195 | + loadNextPage(); |
| 196 | + } |
| 197 | + } |
| 198 | + }); |
| 199 | + NextViewHolder vh = new NextViewHolder(v); |
| 200 | + vh.textView.setText(R.string.load_more); |
| 201 | + return vh; |
| 202 | + } |
| 203 | + default: |
| 204 | + throw new IllegalStateException("Invalid view type: " + viewType); |
| 205 | + } |
| 206 | + } |
| 207 | + |
| 208 | + @Override |
| 209 | + public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { |
| 210 | + switch (getItemViewType(position)) { |
| 211 | + case TYPE_ITEM: { |
| 212 | + ParseObject item = getPager().getObjects().get(position); |
| 213 | + |
| 214 | + ItemViewHolder vh = (ItemViewHolder) holder; |
| 215 | + vh.textView.setText(item.getString("name")); |
| 216 | + } |
| 217 | + break; |
| 218 | + case TYPE_NEXT: { |
| 219 | + NextViewHolder vh = (NextViewHolder) holder; |
| 220 | + vh.setLoading(getPager().isLoadingNextPage()); |
| 221 | + } |
| 222 | + break; |
| 223 | + } |
| 224 | + } |
| 225 | + |
| 226 | + @Override |
| 227 | + public int getItemCount() { |
| 228 | + ParseQueryPager<T> pager = getPager(); |
| 229 | + return pager.getObjects().size() + (pager.hasNextPage() ? 1 : 0); |
| 230 | + } |
| 231 | + |
| 232 | + @Override |
| 233 | + public int getItemViewType(int position) { |
| 234 | + return position < getPager().getObjects().size() ? TYPE_ITEM : TYPE_NEXT; |
| 235 | + } |
| 236 | + |
| 237 | + @Override |
| 238 | + public void registerAdapterDataObserver(RecyclerView.AdapterDataObserver observer) { |
| 239 | + super.registerAdapterDataObserver(observer); |
| 240 | + // We use this method as a notification that the RecyclerView is bound to the adapter. |
| 241 | + loadNextPage(); |
| 242 | + } |
| 243 | + } |
| 244 | +} |
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