scroll down when selecting a category in an image selection quest (ro…

…ad surface, building type, ...) (#170, #770)
streetcomplete · Sep 12, 2018 · c62ec1e · c62ec1e
1 parent bc0e709
commit c62ec1e
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Showing 3 changed files with 45 additions and 14 deletions.
diff --git a/...c/main/java/de/westnordost/streetcomplete/quests/GroupedImageListQuestAnswerFragment.java b/...c/main/java/de/westnordost/streetcomplete/quests/GroupedImageListQuestAnswerFragment.java
@@ -1,7 +1,10 @@
 package de.westnordost.streetcomplete.quests;
 
 import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
 import android.support.annotation.Nullable;
+import android.support.v4.widget.NestedScrollView;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
@@ -32,10 +35,14 @@ public abstract class GroupedImageListQuestAnswerFragment extends AbstractQuestF
 {
 	public static final String OSM_VALUE = "osm_value";
 
+	private final Handler uiThread = new Handler(Looper.getMainLooper());
+
 	protected GroupedImageSelectAdapter imageSelector;
 	private Button showMoreButton;
 	private RecyclerView valueList;
 
+	private NestedScrollView scrollView;
+
 	private List<Item> allItems;
 	private List<Item> topItems;
 
@@ -54,6 +61,8 @@ public abstract class GroupedImageListQuestAnswerFragment extends AbstractQuestF
 	{
 		View view = super.onCreateView(inflater, container, savedInstanceState);
 
+		scrollView = view.findViewById(R.id.scrollView);
+
 		View contentView = setContentView(R.layout.quest_generic_list);
 
 		valueList = contentView.findViewById(R.id.listSelect);
@@ -73,6 +82,27 @@ public abstract class GroupedImageListQuestAnswerFragment extends AbstractQuestF
 
 		imageSelector = new GroupedImageSelectAdapter(lm);
 		imageSelector.addOnItemSelectionListener(item -> checkIsFormComplete());
+		imageSelector.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver()
+		{
+			@Override public void onItemRangeInserted(int positionStart, int itemCount)
+			{
+				super.onItemRangeInserted(positionStart, itemCount);
+
+				View item = lm.getChildAt(Math.max(0,positionStart-1));
+				if(item != null)
+				{
+					int[] itemPos = new int[2];
+					item.getLocationInWindow(itemPos);
+					int[] scrollViewPos = new int[2];
+					scrollView.getLocationInWindow(scrollViewPos);
+
+					uiThread.postDelayed(() ->
+					{
+						scrollView.smoothScrollTo(0,itemPos[1] - scrollViewPos[1]);
+					}, 250);
+				}
+			}
+		});
 		checkIsFormComplete();
 
 		return view;

diff --git a/app/src/main/java/de/westnordost/streetcomplete/view/GroupedImageSelectAdapter.java b/app/src/main/java/de/westnordost/streetcomplete/view/GroupedImageSelectAdapter.java
@@ -95,19 +95,6 @@ private void toggle(int index)
 			selectedItem = null;
 		}
 
-		if(selectedItem != null)
-		{
-			int selectedIndex = items.indexOf(selectedItem);
-			notifyItemChanged(selectedIndex);
-
-			if(selectedItem.isGroup())
-			{
-				if(prevSelectedItem == null || getGroup(items.indexOf(prevSelectedItem)) != selectedIndex )
-				{
-					expandGroup(selectedIndex);
-				}
-			}
-		}
 		if(prevSelectedItem != null)
 		{
 			int prevSelectedIndex = items.indexOf(prevSelectedItem);
@@ -122,6 +109,19 @@ private void toggle(int index)
 				}
 			}
 		}
+		if(selectedItem != null)
+		{
+			int selectedIndex = items.indexOf(selectedItem);
+			notifyItemChanged(selectedIndex);
+
+			if(selectedItem.isGroup())
+			{
+				if(prevSelectedItem == null || getGroup(items.indexOf(prevSelectedItem)) != selectedIndex )
+				{
+					expandGroup(selectedIndex);
+				}
+			}
+		}
 		for (OnItemSelectionListener listener : listeners)
 		{
 			listener.onItemSelected(selectedItem);

diff --git a/app/src/main/res/layout/fragment_quest_answer.xml b/app/src/main/res/layout/fragment_quest_answer.xml
@@ -63,8 +63,9 @@
             </LinearLayout>
 
             <!-- Necessary because even if the bottom sheet is already expanded, the content might
-                 be still too large to fit onto the screen withot scrolling (it often is) -->
+                 be still too large to fit onto the screen without scrolling (it often is) -->
             <android.support.v4.widget.NestedScrollView
+                android:id="@+id/scrollView"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content">