core: prevent some null crash on resource decoding

jadx-core/src/main/java/jadx/core/xmlgen/ResXmlGen.java

@@ -64,7 +64,7 @@ public class ResXmlGen {
 			cw.startLine();
 			cw.add('<').add(ri.getTypeName()).add(' ');
 			String itemTag = "item";
-			if (ri.getTypeName().equals("attr") && ri.getNamedValues().size() > 0) {
+			if (ri.getTypeName().equals("attr") && !ri.getNamedValues().isEmpty()) {
 				cw.add("name=\"").add(ri.getKeyName());
 				int type = ri.getNamedValues().get(0).getRawValue().getData();
 				if ((type & ValuesParser.ATTR_TYPE_ENUM) != 0) {
@@ -126,7 +126,7 @@ public class ResXmlGen {
 		String nameStr = vp.decodeNameRef(value.getNameRef());
 		String valueStr = vp.decodeValue(value.getRawValue());
 		if (!typeName.equals("attr")) {
-			if (valueStr.equals("0")) {
+			if (valueStr == null || valueStr.equals("0")) {
 				valueStr = "@null";
 			}
 			if (nameStr != null) {
@@ -154,6 +154,9 @@ public class ResXmlGen {
 	}
 
 	private void addSimpleValue(CodeWriter cw, String typeName, String itemTag, String attrName, String attrValue, String valueStr) {
+		if (valueStr == null) {
+			return;
+		}
 		if (valueStr.startsWith("res/")) {
 			// remove duplicated resources.
 			return;

jadx-core/src/main/java/jadx/core/xmlgen/entry/ValuesParser.java

@@ -1,8 +1,5 @@
 package jadx.core.xmlgen.entry;
 
-import jadx.core.xmlgen.ParserConstants;
-import jadx.core.xmlgen.ResTableParser;
-
 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -11,9 +8,13 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import jadx.core.xmlgen.ParserConstants;
+import jadx.core.xmlgen.ResTableParser;
+
 public class ValuesParser extends ParserConstants {
 	private static final Logger LOG = LoggerFactory.getLogger(ValuesParser.class);
 
@@ -44,6 +45,7 @@ public class ValuesParser extends ParserConstants {
 		androidResMap = androidParser.getResStorage().getResourcesNames();
 	}
 
+	@Nullable
 	public String getValueString(ResourceEntry ri) {
 		RawValue simpleValue = ri.getSimpleValue();
 		if (simpleValue != null) {
@@ -63,12 +65,14 @@ public class ValuesParser extends ParserConstants {
 		return strList.toString();
 	}
 
+	@Nullable
 	public String decodeValue(RawValue value) {
 		int dataType = value.getDataType();
 		int data = value.getData();
 		return decodeValue(dataType, data);
 	}
 
+	@Nullable
 	public String decodeValue(int dataType, int data) {
 		switch (dataType) {
 			case TYPE_NULL:
@@ -100,7 +104,9 @@ public class ValuesParser extends ParserConstants {
 					if (androidRi != null) {
 						return "@android:" + androidRi;
 					}
-					if (data == 0) return "0";
+					if (data == 0) {
+						return "0";
+					}
 					return "?unknown_ref: " + Integer.toHexString(data);
 				}
 				return "@" + ri;