Make Spinner widget open from start-of-list when nothing is selected (g…

…etodk#1955)

collect_app/src/main/java/org/odk/collect/android/views/ScrolledToTopSpinner.java

@@ -0,0 +1,77 @@
+package org.odk.collect.android.views;
+
+import android.content.Context;
+import android.support.v7.widget.AppCompatSpinner;
+import android.util.AttributeSet;
+
+/**
+ * Copyright 2018 Vaibhav Maheshwari
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * ScrolledToTopSpinner is used in SpinnerWidget so that the spinner scrolls to top
+ * when opened for first time or when last item is selected (which is remove response)
+ */
+
+public class ScrolledToTopSpinner extends AppCompatSpinner {
+
+    private boolean spinnerClicked = false;
+
+    public ScrolledToTopSpinner(Context context, AttributeSet attrs,
+                                int defStyle, int mode) {
+        super(context, attrs, defStyle, mode);
+    }
+
+    public ScrolledToTopSpinner(Context context, AttributeSet attrs,
+                                int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    public ScrolledToTopSpinner(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public ScrolledToTopSpinner(Context context, int mode) {
+        super(context, mode);
+    }
+
+    public ScrolledToTopSpinner(Context context) {
+        super(context);
+    }
+
+    @Override
+    public int getSelectedItemPosition() {
+        // this toggle is required because this method will get called in other
+        // places too, the most important being called for the
+        // OnItemSelectedListener
+        if (spinnerClicked && super.getSelectedItemPosition() == getAdapter().getCount() - 1) {
+            return 0; // get us to the first element
+        }
+        return super.getSelectedItemPosition();
+    }
+
+    @Override
+    public boolean performClick() {
+        // this method shows the list of elements from which to select one.
+        // we have to make the getSelectedItemPosition to return 0 so you can
+        // fool the Spinner and let it think that the selected item is the first
+        // element
+        spinnerClicked = true;
+        boolean result = super.performClick();
+        spinnerClicked = false;
+        return result;
+    }
+
+}

collect_app/src/main/java/org/odk/collect/android/widgets/SpinnerWidget.java

@@ -26,7 +26,6 @@
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemSelectedListener;
 import android.widget.ArrayAdapter;
-import android.widget.Spinner;
 import android.widget.TextView;
 
 import org.javarosa.core.model.SelectChoice;
@@ -38,6 +37,7 @@
 import org.odk.collect.android.R;
 import org.odk.collect.android.application.Collect;
 import org.odk.collect.android.external.ExternalDataUtil;
+import org.odk.collect.android.views.ScrolledToTopSpinner;
 import org.odk.collect.android.widgets.interfaces.MultiChoiceWidget;
 
 import java.util.List;
@@ -52,7 +52,7 @@
 @SuppressLint("ViewConstructor")
 public class SpinnerWidget extends QuestionWidget implements MultiChoiceWidget {
     List<SelectChoice> items;
-    Spinner spinner;
+    ScrolledToTopSpinner spinner;
     String[] choices;
 
     public SpinnerWidget(Context context, FormEntryPrompt prompt) {

collect_app/src/main/res/layout/spinner_layout.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<android.support.v7.widget.AppCompatSpinner xmlns:android="http://schemas.android.com/apk/res/android"
+<org.odk.collect.android.views.ScrolledToTopSpinner xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/spinner"
     style="@style/Base.Widget.AppCompat.Spinner.Underlined"
     android:layout_width="match_parent"