Unity PropertyDrawer for Serializable object - unity3d

Question

I try to draw defualt inspector for serializable object manually , and Here is my code:
[System.Serializable]
public class Item
{
public string Name;
public int ID;
}
[System.Serializable]
public class ItemGroup
{
public Item item;
public int count;
}
public class Test : MonoBehaviour
{
public Item item;
public ItemGroup itemGroup;
public Item[] items;
public ItemGroup[] itemGroups;
}
The default inspector is look like this:
Then I add the PropertyDrawer script for Item and ItemGroup
[CustomPropertyDrawer(typeof(Item))]
public class ItemDrawer : PropertyDrawer
{
public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
{
return EditorGUI.GetPropertyHeight(property, label);
}
public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
var style = new GUIStyle(EditorStyles.foldoutHeader);
style.fontStyle = FontStyle.Normal;
if (property.isExpanded = EditorGUI.BeginFoldoutHeaderGroup(position, property.isExpanded, label, style))
{
EditorGUI.indentLevel++;
position.height = EditorGUIUtility.singleLineHeight;
position.y += position.height;
EditorGUI.PropertyField(position, property.FindPropertyRelative("Name"));
position.y += position.height;
EditorGUI.PropertyField(position, property.FindPropertyRelative("ID"));
EditorGUI.indentLevel--;
}
EditorGUI.EndFoldoutHeaderGroup();
}
}
[CustomPropertyDrawer(typeof(ItemGroup))]
public class ItemGroupDrawer : PropertyDrawer
{
public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
{
return EditorGUI.GetPropertyHeight(property, label);
}
public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
var style = new GUIStyle(EditorStyles.foldoutHeader);
style.fontStyle = FontStyle.Normal;
var itemProperty = property.FindPropertyRelative("item");
var countProperty = property.FindPropertyRelative("count");
position.height = EditorGUIUtility.singleLineHeight;
if (property.isExpanded = EditorGUI.BeginFoldoutHeaderGroup(position, property.isExpanded, label, style))
{
EditorGUI.indentLevel++;
position.y += position.height;
position.height = EditorGUI.GetPropertyHeight(itemProperty);
EditorGUI.PropertyField(position, itemProperty, true);
position.y += position.height;
position.height = EditorGUIUtility.singleLineHeight;
EditorGUI.PropertyField(position, countProperty);
EditorGUI.indentLevel--;
}
EditorGUI.EndFoldoutHeaderGroup();
}
}
Question 1: When Enable ItemDrawer and Disable ItemGroupDrawer, the indent of Item field is wrong, see below.How to make it correct both in ItemGroup class and Array?
[CustomPropertyDrawer(typeof(Item))] //Enable ItemDrawer
//[CustomPropertyDrawer(typeof(ItemGroup))] //Disable ItemGroupDrawer
Question 2: When enable both ItemDrawer and ItemGroupDrawer, there is a error:
but the default inspector it did has foldout header
So how to use PropertyDrawer to draw Item and ItemGroup's properties manually that make it look like default inspector?
I don't want to use EditorGUI.PropertyField(position, property);
I want to draw their properties one by one

Answer 1

The indent is wrong since you pass in the original position without any indentation .. the EditorGUI.indentLevel only directly affects the property fields drawn without a rect bit via EditorGUILayout.
You can get an indented rect however by using
var indentedRect = EditorGUI.IndentedRect(position);
However, until now I don't see a real purpose in having a custom drawer for your types .. what's wrong with the default drawer? ;)

Answer 2

thanks derHugo, I have solved it
Answer 1: I should add position = EditorGUI.IndentedRect(position); to the top of OnGUI
Answer 2: I should use EditorGUI.Foldout rather than EditorGUI.BeginFoldoutHeaderGroup