add/improve topic's behavior on network errors

app/src/main/java/gr/thmmy/mthmmy/activities/topic/TopicActivity.java

@@ -11,6 +11,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.support.design.widget.FloatingActionButton;
+import android.support.design.widget.Snackbar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.app.AppCompatDelegate;
 import android.support.v7.widget.RecyclerView;
@@ -30,7 +31,6 @@ import android.widget.TextView;
 import android.widget.Toast;
 
 import java.util.ArrayList;
-import java.util.Objects;
 
 import gr.thmmy.mthmmy.R;
 import gr.thmmy.mthmmy.activities.topic.tasks.DeleteTask;
@@ -110,6 +110,7 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
     private TextView pageIndicator;
     private ImageButton nextPage;
     private ImageButton lastPage;
+    private Snackbar snackbar;
     private TopicViewModel viewModel;
 
     //Fix for vector drawables on android <21
@@ -449,6 +450,7 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
             @Override
             public void onTopicTaskStarted() {
                 progressBar.setVisibility(ProgressBar.VISIBLE);
+                if (snackbar != null) snackbar.dismiss();
             }
 
             @Override
@@ -469,7 +471,7 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
                 if (result)
                     viewModel.reloadPage();
                 else
-                    Toast.makeText(TopicActivity.this, "Post deleted!", Toast.LENGTH_SHORT).show();
+                    Toast.makeText(getBaseContext(), "Delete failed!", Toast.LENGTH_SHORT).show();
             }
         });
         viewModel.setReplyFinishListener(new ReplyTask.ReplyTaskCallbacks() {
@@ -498,7 +500,7 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
                         viewModel.reloadPage();
                     }
                 } else {
-                    Toast.makeText(TopicActivity.this, "Post failed!", Toast.LENGTH_SHORT).show();
+                    Toast.makeText(getBaseContext(), "Post failed!", Toast.LENGTH_SHORT).show();
                     recyclerView.getChildAt(postsList.size() - 1).setAlpha(1);
                     recyclerView.getChildAt(postsList.size() - 1).setEnabled(true);
                 }
@@ -539,7 +541,7 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
                     viewModel.setEditingPost(false);
                     viewModel.reloadPage();
                 } else {
-                    Toast.makeText(TopicActivity.this, "Edit failed!", Toast.LENGTH_SHORT).show();
+                    Toast.makeText(getBaseContext(), "Edit failed!", Toast.LENGTH_SHORT).show();
                     recyclerView.getChildAt(viewModel.getPostBeingEditedPosition()).setAlpha(1);
                     recyclerView.getChildAt(viewModel.getPostBeingEditedPosition()).setEnabled(true);
                 }
@@ -594,17 +596,37 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
         });
         viewModel.getTopicTaskResultCode().observe(this, resultCode -> {
             if (resultCode == null) return;
+            progressBar.setVisibility(ProgressBar.GONE);
             switch (resultCode) {
                 case SUCCESS:
                     paginationEnabled(true);
-                    progressBar.setVisibility(ProgressBar.GONE);
                     break;
                 case NETWORK_ERROR:
-                    Toast.makeText(getBaseContext(), "Network Error", Toast.LENGTH_SHORT).show();
+                    if (viewModel.getPostsList().getValue() == null) {
+                        // no page has been loaded yet. Give user the ability to refresh
+                        recyclerView.setVisibility(View.GONE);
+                        TextView errorTextview = findViewById(R.id.error_textview);
+                        errorTextview.setText(getString(R.string.network_error_retry_prompt));
+                        errorTextview.setVisibility(View.VISIBLE);
+                        errorTextview.setOnClickListener(view -> {
+                            viewModel.reloadPage();
+                            errorTextview.setVisibility(View.GONE);
+                            recyclerView.setVisibility(View.VISIBLE);
+                        });
+                    } else {
+                        // a page has already been loaded
+                        viewModel.setPageIndicatorIndex(viewModel.getCurrentPageIndex(), false);
+                        snackbar = Snackbar.make(findViewById(R.id.main_content),
+                                R.string.generic_network_error, Snackbar.LENGTH_INDEFINITE);
+                        snackbar.setAction(R.string.retry, view -> viewModel.reloadPage());
+                        snackbar.show();
+                    }
                     break;
                 case UNAUTHORIZED:
-                    progressBar.setVisibility(ProgressBar.GONE);
-                    Toast.makeText(getBaseContext(), "This topic is either missing or off limits to you", Toast.LENGTH_SHORT).show();
+                    recyclerView.setVisibility(View.GONE);
+                    TextView errorTextview = findViewById(R.id.error_textview);
+                    errorTextview.setText(getString(R.string.unauthorized_topic_error));
+                    errorTextview.setVisibility(View.VISIBLE);
                     break;
                 default:
                     //Parse failed - should never happen
@@ -615,26 +637,30 @@ public class TopicActivity extends BaseActivity implements TopicAdapter.OnPostFo
             }
         });
         viewModel.getPrepareForReplyResult().observe(this, prepareForReplyResult -> {
-            if (prepareForReplyResult != null) {
+            progressBar.setVisibility(ProgressBar.GONE);
+            if (prepareForReplyResult != null && prepareForReplyResult.isSuccessful()) {
                 //prepare for a reply
+                viewModel.setWritingReply(true);
                 postsList.add(Post.newQuickReply());
                 topicAdapter.notifyItemInserted(postsList.size());
                 recyclerView.scrollToPosition(postsList.size() - 1);
-                progressBar.setVisibility(ProgressBar.GONE);
                 replyFAB.hide();
                 bottomNavBar.setVisibility(View.GONE);
+            } else {
+                Snackbar.make(findViewById(R.id.main_content), getString(R.string.generic_network_error), Snackbar.LENGTH_SHORT).show();
             }
-
         });
         viewModel.getPrepareForEditResult().observe(this, result -> {
+            progressBar.setVisibility(ProgressBar.GONE);
             if (result != null && result.isSuccessful()) {
                 viewModel.setEditingPost(true);
                 postsList.get(result.getPosition()).setPostType(Post.TYPE_EDIT);
                 topicAdapter.notifyItemChanged(result.getPosition());
                 recyclerView.scrollToPosition(result.getPosition());
-                progressBar.setVisibility(ProgressBar.GONE);
                 replyFAB.hide();
                 bottomNavBar.setVisibility(View.GONE);
+            } else {
+                Snackbar.make(findViewById(R.id.main_content), getString(R.string.generic_network_error), Snackbar.LENGTH_SHORT).show();
             }
         });
     }

app/src/main/java/gr/thmmy/mthmmy/activities/topic/tasks/DeleteTask.java

@@ -41,7 +41,7 @@ public class DeleteTask extends AsyncTask<String, Void, Boolean> {
                     return true;
                 default:
                     Timber.e("Something went wrong. Request string: %s", delete.toString());
-                    return true;
+                    return false;
             }
         } catch (IOException e) {
             Timber.e(e, "Delete failed.");

app/src/main/java/gr/thmmy/mthmmy/activities/topic/tasks/PrepareForReply.java

@@ -33,18 +33,13 @@ public class PrepareForReply extends AsyncTask<Integer, Void, PrepareForReplyRes
 
     @Override
     protected PrepareForReplyResult doInBackground(Integer... postIndices) {
-        String numReplies = null;
-        String seqnum = null;
-        String sc = null;
-        String topic = null;
-        StringBuilder buildedQuotes = new StringBuilder("");
-
         Document document;
         Request request = new Request.Builder()
                 .url(replyPageUrl + ";wap2")
                 .build();
 
         OkHttpClient client = BaseApplication.getInstance().getClient();
+        String numReplies, seqnum, sc, topic;
         try {
             Response response = client.newCall(request).execute();
             document = Jsoup.parse(response.body().string());
@@ -55,14 +50,15 @@ public class PrepareForReply extends AsyncTask<Integer, Void, PrepareForReplyRes
             topic = document.select("input[name=topic]").first().attr("value");
         } catch (IOException | Selector.SelectorParseException e) {
             Timber.e(e, "Prepare failed.");
+            return new PrepareForReplyResult(false, null, null, null, null, null);
         }
 
+        StringBuilder buildedQuotes = new StringBuilder("");
         for (Integer postIndex : postIndices) {
             request = new Request.Builder()
                     .url("https://www.thmmy.gr/smf/index.php?action=quotefast;quote=" +
                            postIndex + ";" + "sesc=" + sc + ";xml")
                     .build();
-
             try {
                 Response response = client.newCall(request).execute();
                 String body = response.body().string();
@@ -70,9 +66,10 @@ public class PrepareForReply extends AsyncTask<Integer, Void, PrepareForReplyRes
                 buildedQuotes.append("\n\n");
             } catch (IOException | Selector.SelectorParseException e) {
                 Timber.e(e, "Quote building failed.");
+                return new PrepareForReplyResult(false, null, null, null, null, null);
             }
         }
-        return new PrepareForReplyResult(numReplies, seqnum, sc, topic, buildedQuotes.toString());
+        return new PrepareForReplyResult(true, numReplies, seqnum, sc, topic, buildedQuotes.toString());
     }
 
     @Override

app/src/main/java/gr/thmmy/mthmmy/activities/topic/tasks/PrepareForReplyResult.java

@@ -2,9 +2,11 @@ package gr.thmmy.mthmmy.activities.topic.tasks;
 
 public class PrepareForReplyResult {
     private final String numReplies, seqnum, sc, topic, buildedQuotes;
+    private boolean successful;
 
 
-    public PrepareForReplyResult(String numReplies, String seqnum, String sc, String topic, String buildedQuotes) {
+    public PrepareForReplyResult(boolean successful, String numReplies, String seqnum, String sc, String topic, String buildedQuotes) {
+        this.successful = successful;
         this.numReplies = numReplies;
         this.seqnum = seqnum;
         this.sc = sc;
@@ -31,4 +33,8 @@ public class PrepareForReplyResult {
     public String getBuildedQuotes() {
         return buildedQuotes;
     }
+
+    public boolean isSuccessful() {
+        return successful;
+    }
 }

app/src/main/java/gr/thmmy/mthmmy/utils/ScrollAwareFABBehavior.java

@@ -4,13 +4,14 @@ import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.design.widget.CoordinatorLayout;
 import android.support.design.widget.FloatingActionButton;
+import android.support.design.widget.Snackbar;
 import android.support.v4.view.ViewCompat;
 import android.util.AttributeSet;
 import android.view.View;
 
 /**
  * Extends FloatingActionButton's behavior so the button will hide when scrolling down and show
- * otherwise.
+ * otherwise. It also lifts the {@link FloatingActionButton} when a {@link Snackbar} is shown.
  */
 @SuppressWarnings("unused")
 public class ScrollAwareFABBehavior extends CoordinatorLayout.Behavior<FloatingActionButton> {
@@ -48,4 +49,16 @@ public class ScrollAwareFABBehavior extends CoordinatorLayout.Behavior<FloatingA
             child.show();
         }
     }
+
+    @Override
+    public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
+        return dependency instanceof Snackbar.SnackbarLayout;
+    }
+
+    @Override
+    public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
+        float translationY = Math.min(0, dependency.getTranslationY() - dependency.getHeight());
+        child.setTranslationY(translationY);
+        return true;
+    }
 }

app/src/main/java/gr/thmmy/mthmmy/utils/ScrollAwareLinearBehavior.java

@@ -4,6 +4,7 @@ import android.animation.Animator;
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.design.widget.CoordinatorLayout;
+import android.support.design.widget.Snackbar;
 import android.support.v4.view.ViewCompat;
 import android.support.v4.view.animation.FastOutSlowInInterpolator;
 import android.util.AttributeSet;
@@ -13,7 +14,9 @@ import android.view.ViewPropertyAnimator;
 /**
  * Extends LinearLayout's behavior. Used for bottom navigation bar.
  * <p>When a nested ScrollView is scrolled down, the view will disappear.
- * When the ScrollView is scrolled back up, the view will reappear.</p>
+ * When the ScrollView is scrolled back up, the view will reappear. It also pushes the
+ * {@link android.widget.LinearLayout} up when a {@link Snackbar} is shown
+ * </p>
  */
 @SuppressWarnings("unused")
 public class ScrollAwareLinearBehavior extends CoordinatorLayout.Behavior<View> {
@@ -111,4 +114,16 @@ public class ScrollAwareLinearBehavior extends CoordinatorLayout.Behavior<View>
 
         animator.start();
     }
+
+    @Override
+    public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
+        return dependency instanceof Snackbar.SnackbarLayout;
+    }
+
+    @Override
+    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
+        float translationY = Math.min(0, dependency.getTranslationY() - dependency.getHeight());
+        child.setTranslationY(translationY);
+        return true;
+    }
 }

app/src/main/java/gr/thmmy/mthmmy/viewmodel/TopicViewModel.java

@@ -84,7 +84,7 @@ public class TopicViewModel extends BaseViewModel implements TopicTask.OnTopicTa
     }
 
     public void reloadPage() {
-        if (topicUrl == null) throw new NullPointerException("No topic task has finished yet!");
+        if (topicUrl == null) throw new NullPointerException("No topic task has been requested yet!");
         loadUrl(topicUrl);
     }
 
@@ -194,7 +194,6 @@ public class TopicViewModel extends BaseViewModel implements TopicTask.OnTopicTa
 
     @Override
     public void onPrepareForReplyFinished(PrepareForReplyResult result) {
-        writingReply = true;
         prepareForReplyResult.setValue(result);
     }
 
@@ -207,26 +206,31 @@ public class TopicViewModel extends BaseViewModel implements TopicTask.OnTopicTa
     public void incrementPageRequestValue(int step, boolean changePage) {
         if (pageIndicatorIndex.getValue() == null)
             throw new NullPointerException("No page has been loaded yet!");
-        if (pageIndicatorIndex.getValue() <= pageCount - step) {
+        int oldIndicatorIndex = pageIndicatorIndex.getValue();
+        if (oldIndicatorIndex <= pageCount - step) {
             pageIndicatorIndex.setValue(pageIndicatorIndex.getValue() + step);
         } else
             pageIndicatorIndex.setValue(pageCount);
-        if (changePage) performPageChange();
+        if (changePage && oldIndicatorIndex != pageIndicatorIndex.getValue()) performPageChange();
     }
 
     public void decrementPageRequestValue(int step, boolean changePage) {
         if (pageIndicatorIndex.getValue() == null)
             throw new NullPointerException("No page has been loaded yet!");
-        if (pageIndicatorIndex.getValue() >= step) {
+        int oldIndicatorIndex = pageIndicatorIndex.getValue();
+        if (oldIndicatorIndex > step) {
             pageIndicatorIndex.setValue(pageIndicatorIndex.getValue() - step);
         } else
             pageIndicatorIndex.setValue(1);
-        if (changePage) performPageChange();
+        if (changePage && oldIndicatorIndex != pageIndicatorIndex.getValue()) performPageChange();
     }
 
     public void setPageIndicatorIndex(int pageIndicatorIndex, boolean changePage) {
+        if (this.pageIndicatorIndex.getValue() == null)
+            throw new NullPointerException("No page has been loaded yet!");
+        int oldIndicatorIndex = this.pageIndicatorIndex.getValue();
         this.pageIndicatorIndex.setValue(pageIndicatorIndex);
-        if (changePage) performPageChange();
+        if (changePage && oldIndicatorIndex != this.pageIndicatorIndex.getValue()) performPageChange();
     }
 
     // <-------------Just getters, setters and helper methods below here---------------->

app/src/main/res/layout/activity_topic.xml

@@ -47,6 +47,16 @@
         app:layout_behavior="@string/appbar_scrolling_view_behavior">
     </android.support.v7.widget.RecyclerView>
 
+    <TextView
+        android:id="@+id/error_textview"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:text="@string/network_error_retry_prompt"
+        android:textSize="32sp"
+        android:textColor="@color/white"
+        android:gravity="center"
+        android:visibility="gone" />
+
     <LinearLayout
         android:id="@+id/bottom_navigation_bar"
         android:layout_width="match_parent"

app/src/main/res/values/strings.xml

@@ -53,6 +53,10 @@
     <string name="subject">Subject&#8230;</string>
     <string name="submit">Submit</string>
     <string name="post_message">Message&#8230;</string>
+    <string name="network_error_retry_prompt">Could not connect to thmmy.gr \n\n Tap to retry</string>
+    <string name="generic_network_error">Network error</string>
+    <string name="retry">retry</string>
+    <string name="unauthorized_topic_error">This topic is either missing or off limits to you</string>
 
     <!--Profile Activity-->
     <string name="username">Username</string>