Show user selection view dynamically

res/layout/view_user_selection.xml

@@ -3,5 +3,5 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/userSelectionView"
     android:layout_width="match_parent"
-    android:layout_height="200dp"
+    android:layout_height="0dp"
     android:paddingTop="6dp" />

src/org/thoughtcrime/securesms/conversation/ConversationActivity.java

@@ -244,6 +244,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import network.loki.messenger.R;
+import nl.komponents.kovenant.combine.Tuple2;
 
 import static org.thoughtcrime.securesms.TransportOption.Type;
 import static org.thoughtcrime.securesms.database.GroupDatabase.GroupRecord;
@@ -313,6 +314,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   private   Stub<UnverifiedBannerView>  unverifiedBannerView;
   private   Stub<GroupShareProfileView> groupShareProfileView;
   private   TypingStatusTextWatcher     typingTextWatcher;
+  private   MentionTextWatcher          mentionTextWatcher;
   private   ConversationSearchBottomBar searchNav;
   private   MenuItem                    searchViewItem;
 
@@ -342,6 +344,8 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   private final DynamicNoActionBarTheme dynamicTheme    = new DynamicNoActionBarTheme();
   private final DynamicLanguage         dynamicLanguage = new DynamicLanguage();
 
+  private UserSelectionView userSelectionView;
+  private int               mentionStartIndex = -1;
 
   @Override
   protected void onPreCreate() {
@@ -393,16 +397,13 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
               composeText.addTextChangedListener(typingTextWatcher);
             }
             composeText.setSelection(composeText.length(), composeText.length());
+            composeText.addTextChangedListener(mentionTextWatcher);
           }
         });
       }
     });
 
     LokiAPIUtilities.INSTANCE.populateUserIDCacheIfNeeded(threadId, this);
-    UserSelectionView userSelectionView = findViewById(R.id.userSelectionView);
-    LokiUserDatabase userDatabase = DatabaseFactory.getLokiUserDatabase(this);
-    userSelectionView.setHasGroupContext(true);
-    userSelectionView.setUsers(LokiAPI.Companion.getUserIDs("", threadId, userDatabase));
 
     if (this.recipient.isGroupRecipient()) {
       if (this.recipient.getName().equals("Loki Public Chat")) {
@@ -1562,6 +1563,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     inlineAttachmentToggle = ViewUtil.findById(this, R.id.inline_attachment_container);
     inputPanel             = ViewUtil.findById(this, R.id.bottom_panel);
     searchNav              = ViewUtil.findById(this, R.id.conversation_search_nav);
+    userSelectionView      = ViewUtil.findById(this, R.id.userSelectionView);
 
     ImageButton quickCameraToggle      = ViewUtil.findById(this, R.id.quick_camera_toggle);
     ImageButton inlineAttachmentButton = ViewUtil.findById(this, R.id.inline_attachment_button);
@@ -1574,6 +1576,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     attachmentManager      = new AttachmentManager(this, this);
     audioRecorder          = new AudioRecorder(this);
     typingTextWatcher      = new TypingStatusTextWatcher();
+    mentionTextWatcher     = new MentionTextWatcher();
 
     SendButtonListener        sendButtonListener        = new SendButtonListener();
     ComposeKeyPressedListener composeKeyPressedListener = new ComposeKeyPressedListener();
@@ -2601,7 +2604,9 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
 
   private void silentlySetComposeText(String text) {
     typingTextWatcher.setEnabled(false);
+    mentionTextWatcher.setEnabled(false);
     composeText.setText(text);
+    mentionTextWatcher.setEnabled(true);
     typingTextWatcher.setEnabled(true);
   }
 
@@ -2716,7 +2721,6 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   }
 
   private class TypingStatusTextWatcher extends SimpleTextWatcher {
-
     private boolean enabled = true;
 
     @Override
@@ -2731,6 +2735,36 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     }
   }
 
+  private class MentionTextWatcher extends SimpleTextWatcher {
+    private boolean enabled = true;
+
+    @Override
+    public void onTextChanged(String text) {
+      if (!enabled) { return; }
+      int currentEndIndex = (text.length() != 0) ? text.length() - 1 : 0;
+      char lastCharacter = text.charAt(currentEndIndex);
+      LokiUserDatabase userDatabase = DatabaseFactory.getLokiUserDatabase(ConversationActivity.this);
+      if (lastCharacter == '@') {
+        List<Tuple2<String, String>> users = LokiAPI.Companion.getUsers("", threadId, userDatabase);
+        mentionStartIndex = currentEndIndex + 1;
+        userSelectionView.show(users, threadId);
+      } else if (!Character.isAlphabetic(lastCharacter) || !Character.isUpperCase(lastCharacter) || !Character.isLowerCase(lastCharacter)) {
+        mentionStartIndex = -1;
+        userSelectionView.hide();
+      } else {
+        if (mentionStartIndex != -1) {
+          String query = text.substring(mentionStartIndex);
+          List<Tuple2<String, String>> users = LokiAPI.Companion.getUsers(query, threadId, userDatabase);
+          userSelectionView.show(users, threadId);
+        }
+      }
+    }
+
+    public void setEnabled(boolean enabled) {
+      this.enabled = enabled;
+    }
+  }
+
   @Override
   public void setThreadId(long threadId) {
     this.threadId = threadId;

src/org/thoughtcrime/securesms/loki/UserSelectionView.kt

@@ -8,11 +8,12 @@ import android.view.ViewGroup
 import android.widget.BaseAdapter
 import android.widget.ListView
 import nl.komponents.kovenant.combine.Tuple2
+import org.thoughtcrime.securesms.database.DatabaseFactory
 
 class UserSelectionView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : ListView(context, attrs, defStyleAttr) {
-    var users = listOf<Tuple2<String, String>>()
+    private var users = listOf<Tuple2<String, String>>()
         set(newValue) { field = newValue; userSelectionViewAdapter.users = newValue }
-    var hasGroupContext = false
+    private var hasGroupContext = false
 
     private val userSelectionViewAdapter by lazy { Adapter(context) }
 
@@ -49,4 +50,18 @@ class UserSelectionView(context: Context, attrs: AttributeSet?, defStyleAttr: In
         adapter = userSelectionViewAdapter
         userSelectionViewAdapter.users = users
     }
+
+    fun show(users: List<Tuple2<String, String>>, threadID: Long) {
+        hasGroupContext = DatabaseFactory.getThreadDatabase(context).getRecipientForThreadId(threadID)!!.isGroupRecipient
+        this.users = users
+        val layoutParams = this.layoutParams as ViewGroup.LayoutParams
+        layoutParams.height = toPx(6 + Math.min(users.count(), 4) * 52, resources)
+        this.layoutParams = layoutParams
+    }
+
+    fun hide() {
+        val layoutParams = this.layoutParams as ViewGroup.LayoutParams
+        layoutParams.height = 0
+        this.layoutParams = layoutParams
+    }
 }