Fix DataFormProvider parsing 'fixed' FormFields

b71039660b made FormField.setType(Type)
throw an illegal argument exception if type is fixed, but the
DataFormProvider was not changed, so it still would call
setType(Type.fixed).

Change DataFormProvider so that the non-argument constructer of
FormField is used when type == fixed.

smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/FormField.java

@@ -113,7 +113,16 @@ public class FormField implements NamedElement {
             }
         }
 
+        /**
+         * Get a form field type from the given string. If <code>string</code> is null, then null will be returned.
+         *
+         * @param string the string to transform or null.
+         * @return the type or null.
+         */
         public static Type fromString(String string) {
+            if (string == null) {
+                return null;
+            }
             switch (string) {
             case "boolean":
                 return bool;

smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/provider/DataFormProvider.java

@@ -94,12 +94,18 @@ public class DataFormProvider extends PacketExtensionProvider<DataForm> {
 
     private FormField parseField(XmlPullParser parser) throws XmlPullParserException, IOException {
         final int initialDepth = parser.getDepth();
-        FormField formField = new FormField(parser.getAttributeValue("", "var"));
+        final String var = parser.getAttributeValue("", "var");
-        formField.setLabel(parser.getAttributeValue("", "label"));
+        final FormField.Type type = FormField.Type.fromString(parser.getAttributeValue("", "type"));
-        String typeString = parser.getAttributeValue("", "type");
+
-        if (typeString != null) {
+        final FormField formField;
-            formField.setType(FormField.Type.fromString(typeString));
+        if (type == FormField.Type.fixed) {
+            formField = new FormField();
+        } else {
+            formField = new FormField(var);
+            formField.setType(type);
         }
+        formField.setLabel(parser.getAttributeValue("", "label"));
+
         outerloop: while (true) {
             int eventType = parser.next();
             switch (eventType) {

smack-extensions/src/test/java/org/jivesoftware/smackx/xdata/packet/DataFormTest.java

@@ -25,6 +25,7 @@ import org.jivesoftware.smack.SmackException;
 import org.jivesoftware.smack.packet.Element;
 import org.jivesoftware.smack.util.PacketParserUtils;
 import org.jivesoftware.smackx.xdata.FormField;
+import org.jivesoftware.smackx.xdata.FormField.Type;
 import org.jivesoftware.smackx.xdata.provider.DataFormProvider;
 import org.jivesoftware.smackx.xdatalayout.packet.DataLayout;
 import org.jivesoftware.smackx.xdatalayout.packet.DataLayout.Fieldref;
@@ -32,7 +33,6 @@ import org.jivesoftware.smackx.xdatalayout.packet.DataLayout.Section;
 import org.jivesoftware.smackx.xdatalayout.packet.DataLayout.Text;
 import org.jivesoftware.smackx.xdatavalidation.packet.ValidateElement;
 import org.jivesoftware.smackx.xdatavalidation.packet.ValidateElement.RangeValidateElement;
-
 import org.junit.Test;
 import org.xmlpull.v1.XmlPullParser;
 import org.xmlpull.v1.XmlPullParserException;
@@ -48,6 +48,8 @@ public class DataFormTest {
     private static final String TEST_OUTPUT_2 = "<x xmlns='jabber:x:data' type='submit'><instructions>InstructionTest1</instructions><field var='testField1'></field><page xmlns='http://jabber.org/protocol/xdata-layout' label='Label'><fieldref var='testField1'/><section label='section Label'><text>SectionText</text></section><text>PageText</text></page></x>";
     private static final String TEST_OUTPUT_3 = "<x xmlns='jabber:x:data' type='submit'><instructions>InstructionTest1</instructions><field var='testField1'><validate xmlns='http://jabber.org/protocol/xdata-validate' datatype='xs:integer'><range min='1111' max='9999'/></validate></field></x>";
 
+    DataFormProvider pr = new DataFormProvider();
+
     @Test
     public void test() throws XmlPullParserException, IOException, SmackException {
         //Build a Form
@@ -61,8 +63,6 @@ public class DataFormTest {
         String output = df.toXML().toString();
         assertEquals(TEST_OUTPUT_1, output);
         
-        DataFormProvider pr = new DataFormProvider();
-        
         XmlPullParser parser = PacketParserUtils.getParserFor(output);
         
         df = pr.parse(parser);
@@ -101,8 +101,6 @@ public class DataFormTest {
         String output = df.toXML().toString();
         assertEquals(TEST_OUTPUT_2, output);
         
-        DataFormProvider pr = new DataFormProvider();
-        
         XmlPullParser parser = PacketParserUtils.getParserFor(output);
         
         df = pr.parse(parser);
@@ -137,8 +135,6 @@ public class DataFormTest {
         String output = df.toXML().toString();
         assertEquals(TEST_OUTPUT_3, output);
         
-        DataFormProvider pr = new DataFormProvider();
-        
         XmlPullParser parser = PacketParserUtils.getParserFor(output);
         
         df = pr.parse(parser);
@@ -156,4 +152,11 @@ public class DataFormTest {
         output = df.toXML().toString();
         assertEquals(TEST_OUTPUT_3, output);
     }
+
+    @Test
+    public void testFixedField() throws XmlPullParserException, IOException, SmackException {
+        final String formWithFixedField = "<x xmlns='jabber:x:data' type='submit'><instructions>InstructionTest1</instructions><field type='fixed'></field></x>";
+        DataForm df = pr.parse(PacketParserUtils.getParserFor(formWithFixedField));
+        assertEquals(Type.fixed, df.getFields().get(0).getType());
+    }
 }