Question

我正在尝试在xamarin android.I中开发一个TreeView，然后按照Link来开发下面的示例。

我不知道如何更改TreeNode的前景色，即parent和child1，它们是Linear Layout的一部分。

我可以更改TreeItems的颜色，因为我在TextView中显示TreeItems。

非常感谢任何帮助。

我的MainActivity.cs：

namespace XamarinTreeView
{
[Activity(Label = "XamarinTreeView", MainLauncher = true)]
public class MainActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);
        //create root
        TreeNode root = TreeNode.InvokeRoot();
        TreeNode parent = new TreeNode("parent2");

        ///Parent2 root children
        TreeNode child1 = new TreeNode("Child1");
        TreeItem item = new TreeItem() { text = " Level1" };

        TreeNode child10 = new TreeNode(item).SetViewHolder(new MyHolder(this));
        child1.AddChild(child10);
        TreeItem item1 = new TreeItem() { text = " Level2" };
        TreeNode child11 = new TreeNode(item1).SetViewHolder(new MyHolder(this));
        child10.AddChild(child11);
        TreeItem item2 = new TreeItem() { text = " Level2-1" };
        TreeNode child111_1 = new TreeNode(item2).SetViewHolder(new MyHolder(this));
        child11.AddChild(child111_1);
        TreeItem item3 = new TreeItem() { text = " Level2-2" };
        TreeNode child111_2 = new TreeNode(item3).SetViewHolder(new MyHolder(this));
        child11.AddChild(child111_2);
        ///

        parent.AddChildren(child1);          
        root.AddChild(parent);


        AndroidTreeView atv = new AndroidTreeView(this, root);
        LinearLayout rootlayout = FindViewById<LinearLayout>(Resource.Id.rootlayout);
        rootlayout.AddView(atv.View);
        rootlayout.Invalidate();          
    }
}

public class TreeItem : Java.Lang.Object
{
    public string text;
}
}

Main.axml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rootlayout">
</LinearLayout>

Answer 1

创建一个新类来表示TreeNode，就像您对TreeItem一样。像TreeItem（MyHolder.cs）一样创建一个新的持有者。像TreeItem（itemview.axml）

一样创建一个新的布局

MyNodeHolder.cs

public class MyNodeHolder : TreeNode.BaseNodeViewHolder
{

    private Context mcontext;

    public MyNodeHolder(Context context) : base(context)
    {
        mcontext = context;
    }

    public override View CreateNodeView(TreeNode p0, Java.Lang.Object p1)
    {
        var inflater = LayoutInflater.FromContext(mcontext);
        var view = inflater.Inflate(Resource.Layout.nodeview, null, false);
        TextView tv = view.FindViewById<TextView>(Resource.Id.nodetv);
        var item = p1 as TreeNodeItem;

        tv.Text = item.text;
        return view;
    }
}

nodeview.axml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/darker_gray">
<TextView
    android:id="@+id/nodetv"
    android:layout_height="wrap_content"
    android:layout_width="match_parent" />
</LinearLayout>

在活动中创建您的节点：

 streetNode.AddChild(streetNumberNode.SetViewHolder(new MyNodeHolder(this)));

我希望它有所帮助。

如何在xamarin android中更改treenode的前景色

1 个答案: