緣起：把前面寫的二篇合併起來，存到一個獨立類別檔，以便日後調用
Android 算法：遍歷巡覽ViewGroup找出所有子View[C# 替代Java的findViewsWithText方法]
Android 算法：遍歷巡覽ViewGroup找出所有子View[C# 以Xml方法3種實作] GetElementsByTagName、SelectNodes
GameActivity.cs
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void setNumBtnEnabled(bool setEnabled)
{
List<View> vList = new List<View>();
MyViewGroup myViewGroup = new MyViewGroup(this);
myViewGroup.FindViewsWithText(ref vList,
MyViewGroup.whatTraverseMethodToBeRun.withoutRecursion);
foreach (View item in vList)
{
item.Enabled = setEnabled;
}
}
MyViewGroup.cs
using Android.Content;
using Android.Views;
using Android.Util;
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using Android.Widget;
using System.Xml;
using Android.Content.Res;
using Android.App;
namespace GuessGameAndroidPractise
{
public class MyViewGroup : ViewGroup
{
//Called from layout when this view should assign a size and position to each of its children.
//https://docs.microsoft.com/zh-tw/dotnet/api/android.views.viewgroup.onlayout?view=xamarin-android-sdk-9#Android_Views_ViewGroup_OnLayout_System_Boolean_System_Int32_System_Int32_System_Int32_System_Int32_
int _childCount = 0;
public new int ChildCount { get => _childCount; set => _childCount = value; }
Context _context1; static Activity activity;
public MyViewGroup(Context context) : base(context)
{
_context1 = context;
activity = (Activity)_context1;//https://stackoverflow.com/questions/9891360/getting-activity-from-context-in-android
}
protected override void OnLayout(bool changed, int l, int t, int r, int b)
{
//throw new System.NotImplementedException();
if (changed)
{
Left = l; Top = t;
Right = r; Bottom = b;
}
else
{
Left = l; Top = t;
Right = r; Bottom = b;
}
}
public enum whatTraverseMethodToBeRun
{
xml, recursion, withoutRecursion
}
//巡覽遍歷想要找的View，並取得List<View>，以便於對此群組作統一的操作
public void FindViewsWithText(//traverse_any_view_hierarchy_in_android
ref List<View> vList,whatTraverseMethodToBeRun method,
chooseAXmlMethodforTraverseViewGroup c
= chooseAXmlMethodforTraverseViewGroup.SelectNodes,
string contentDescription = "buttonNum",
string nodeForGot = "Button", string attributeName = "contentDescription",
int attributevalue = Resource.String.buttonNum,
int layoutXmlFileName = Resource.Layout.activity_game,
int layoutID=Resource.Id.linearLayoutGame)
{
//凡4種方式來巡覽遍歷所有的 View Button：
switch (method)
{
case whatTraverseMethodToBeRun.xml:
switch (c)
{
case chooseAXmlMethodforTraverseViewGroup.GetElementsByTagName:
case chooseAXmlMethodforTraverseViewGroup.SelectNodes:
case chooseAXmlMethodforTraverseViewGroup.SelectNodes_XmlNamespaceManager:
traverseViewGroup_Xml(ref vList, c, nodeForGot
, attributeName, attributevalue, layoutXmlFileName);
break;
default:
break;
}
break;
case whatTraverseMethodToBeRun.recursion:
View view = activity.FindViewById<LinearLayout>(layoutID);
int viewsCount = traverseViewGroup_recursion(ref vList,
view, contentDescription);//遞歸（recursion）
break;
case whatTraverseMethodToBeRun.withoutRecursion:
View v = activity.FindViewById<LinearLayout>(layoutID);
int viewsCnt = traverseViewGroup(ref vList,
v, contentDescription);//不遞迴（recursion）
break;
default:
break;
}
}
public enum chooseAXmlMethodforTraverseViewGroup
{
GetElementsByTagName, SelectNodes, SelectNodes_XmlNamespaceManager
}
//用Xml提供的方法來遍歷巡覽View https://docs.microsoft.com/zh-tw/dotnet/api/system.xml.xmlnode.selectnodes?view=netcore-3.1
void traverseViewGroup_Xml(ref List<View> vList,
chooseAXmlMethodforTraverseViewGroup c,
string nodeForGot = "Button", string attributeName = "contentDescription",
int attributevalue = Resource.String.buttonNum,
int layoutID = Resource.Layout.activity_game
)
{
XmlDocument doc = new XmlDocument();
doc.Load(Resources.GetLayout(layoutID));
XmlElement xmlElement = doc.DocumentElement;
XmlNodeList xmlNodeList = doc.ChildNodes;
switch (c)
{
case chooseAXmlMethodforTraverseViewGroup.GetElementsByTagName:
xmlNodeList = doc.GetElementsByTagName(nodeForGot);
break;
case chooseAXmlMethodforTraverseViewGroup.SelectNodes:
xmlNodeList = xmlElement.SelectNodes("//" + nodeForGot);//case-sensitive
break;
case chooseAXmlMethodforTraverseViewGroup.SelectNodes_XmlNamespaceManager:
XmlNamespaceManager xmlNamespaceManager = new XmlNamespaceManager(doc.NameTable);
xmlNamespaceManager.AddNamespace("android", "http://schemas.android.com/apk/res/android");
xmlNodeList = xmlElement.SelectNodes("//" + nodeForGot, xmlNamespaceManager);
break;
default:
break;
}
if (xmlNodeList.Count != doc.ChildNodes.Count)//因為以doc.ChildNodes初始化故
{
foreach (XmlNode item in xmlNodeList)
{
XmlAttribute attributeContentDescription = item.Attributes["p0:" + attributeName];
if (attributeContentDescription != null)//具有指定名稱的屬性。 如果屬性 (attribute) 不存在，這個屬性 (property) 會傳回 null。https://docs.microsoft.com/zh-tw/dotnet/api/system.xml.xmlattributecollection.itemof?view=netcore-3.1#System_Xml_XmlAttributeCollection_ItemOf_System_String_
{
string valueAttributeContentDescription = attributeContentDescription.Value;
if (valueAttributeContentDescription != null &&
valueAttributeContentDescription.Contains//如果是數字按鈕
(Convert.ToString(attributevalue)))//因屬性值前有1個「@」
{
//View gameActivity = new View(_context1);
vList.Add(activity.FindViewById<Button>
(int.Parse(item.Attributes["p0:id"].Value
.Substring(1))));
}
}
}
}
}
////用XmlDocument.GetElementsByTagName 方法來遍歷巡覽View https://docs.microsoft.com/zh-tw/dotnet/api/system.xml.xmldocument.getelementsbytagname?view=netcore-3.1#System_Xml_XmlDocument_GetElementsByTagName_System_String_
//void traverseViewGroup_GetElementsByTagName_EnabledFalse()
//{
// XmlDocument doc = new XmlDocument();
// //XmlReader xmrder = Application.Resources.GetLayout(2131427356);
// XmlReader xmrder = Application.Resources.GetLayout(Resource.Layout.activity_game);
// doc.Load(xmrder);
// //下列網頁說明所示的R類別，其實是Java中的實作，在C#中則是如上，直接用「Resources」這個類別，就是R類別！
// //doc=R.layout.activity_game;// error :https://developer.android.com/guide/topics/resources/accessing-resources#ResourcesFromCode
// XmlNodeList xmlNodeList = doc.GetElementsByTagName("Button");
// foreach (XmlNode item in xmlNodeList)
// {
// XmlAttribute xAtt = item.Attributes["p0:contentDescription"];
// if (xAtt != null)
// {
// //以上2行為優化，與下2行等效
// //foreach (XmlAttribute xa in item.Attributes)
// //{
// // //if (xa.Name=="p0:contentDescription")//與以下一行同
// // if (xa.Name.Contains("contentDescription"))
// // {
// //string contentDescription = item.Attributes["p0:contentDescription"].Value;
// string contentDescription = xAtt.Value;
// if (contentDescription != null
// && contentDescription.Contains("@" + Resource.String.buttonNum))
// {
// FindViewById<Button>
// (int.Parse(item.Attributes["p0:id"].Value.Substring(1)))
// .Enabled = false;//Name="p0:id", Value="@2131230760"//要去掉首位「@」符
// //break; //foreach (XmlAttribute xa in item.Attributes)
// }
// // }
// //}
// }
// }
//}
//用遞迴。〈Android 算法：遍历ViewGroup找出所有子View〉https://blog.csdn.net/l707941510/article/details/82912526
int traverseViewGroup_recursion(ref List<View> vList,
View view, string contentDescription = "buttonNum")//Passing Parameters (C# Programming Guide):https://docs.microsoft.com/zh-tw/dotnet/csharp/programming-guide/classes-and-structs/passing-parameters
{
if (view == null) return 0;
int viewCount = 0;//宣告應該在遞歸（recursion）時不會被覆寫，因其有int冠前也
//https://docs.microsoft.com/zh-tw/dotnet/api/system.type.isinstanceoftype?view=netcore-3.1
var abstractType = typeof(ViewGroup);
if (abstractType.IsInstanceOfType(view))
{
ViewGroup vg = (ViewGroup)view;//要取用ChildCount屬性、GetChildAt方法須轉型為子類別，子類別ViewGroup才有定義此屬性、方法
for (int i = 0; i < vg.ChildCount; i++)
{
View vw = vg.GetChildAt(i);
if (abstractType.IsInstanceOfType(vw))
{
//遞歸（recursion）
viewCount +=
traverseViewGroup_recursion(
ref vList, vw, contentDescription);
}
else
{
viewCount++;
var cntDscrpt = vw.ContentDescription;
if (cntDscrpt != null &&
cntDscrpt.IndexOf(contentDescription) > -1)
vList.Add(vw);
}
}
}
else
{
viewCount++;
var cntDscrpt = view.ContentDescription;
if (cntDscrpt != null
&& cntDscrpt.IndexOf(contentDescription) > -1)
vList.Add(view);
}
return viewCount;
}
//不用遞迴（recursion）
int traverseViewGroup(
ref List<View> vList, View view,
string contentDescription = "buttonNum")
{
if (view == null) return 0;
int viewCount = 0;
var abstractType = typeof(ViewGroup);
if (abstractType.IsInstanceOfType(view))
{
List<ViewGroup> lVg = new List<ViewGroup>();
ViewGroup vg = (ViewGroup)view;
lVg.Add(vg);
while (lVg.Count > 0)
{
vg = lVg[0];
lVg.RemoveAt(0);
for (int i = 0; i < vg.ChildCount; i++)
{
var vw = vg.GetChildAt(i);
if (abstractType.IsInstanceOfType(vw))
{
lVg.Add((ViewGroup)vw);
}
else
{
viewCount++;
var cntDscrp = vw.ContentDescription;
if (cntDscrp != null &&
cntDscrp.IndexOf(contentDescription) > -1)
vList.Add(vw);
}
}
}
}
else
{
viewCount++;
var cntDscrp = view.ContentDescription;
if (cntDscrp != null &&
cntDscrp.IndexOf(contentDescription) > -1)
vList.Add(view);
}
return viewCount;
}
public override void FindViewsWithText(IList<View> outViews,
Java.Lang.ICharSequence text, FindViewsWith flags)
{
//Java super是調用父類別的指標/參考,C#則是 base
//super.findViewsWithText(outViews, text, flags);
base.FindViewsWithText(outViews, text, flags);
int mChildrenCount = ChildCount;
//Java final相當於 C# const 或 Readonly
//final int childrenCount = mChildrenCount;
int childrenCount = mChildrenCount;
//final View[] children = mChildren;
//View[] children = mChildren;
for (int i = 0; i < childrenCount; i++)
{
//View child = children[i];
if (GetChildAt(i) != null)
{
MyView child = new MyView(GetChildAt(i));
//if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE &&
// (child.mPrivateFlags & PFLAG_IS_ROOT_NAMESPACE) == 0)
if (child._v.Visibility == ViewStates.Visible &&
child._v.RootView != null)
{
child.FindViewsWithText(outViews, text, flags);
}
}
}
}
}
}
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