ListView 项目作为进度条

Question

我想知道是否有人可以帮助我实现以下目的：

我创建了一个只显示 table 的应用程序。它显示了一个 table 头部和一个包含多个项目的列表视图。

是否有可能，如果点击这些项目之一，会显示一个进度条，该进度条会在特定时间间隔（比如 30 秒）内从左到右平稳加载？

请看下面我的截图，也许更容易理解我想做什么：

最后，不知道有没有帮助，还是附上一些代码吧。我把它缩短了一点，如果缺少理解的东西（比如列表class）或者如果我删除了很多，请告诉我：

public class TableActivity : Activity
{
    ListView lv;
    ListAdapter adapter = null;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        //...
        lv = FindViewById<ListView>(Resource.Id.geraeteListView);
        adapter = new ListAdapter(this, Resource.Layout.List, geraeteliste.CurrentGeraeteliste, Intent.GetStringExtra("ServerIP"))
        {
            parentActivity = this
        };
        lv.Adapter = adapter;
    }

    private async void OnItemClick(object sender, AdapterView.ItemClickEventArgs e)
    {
        if (geraeteliste.CurrentGeraeteliste[e.Position].bespielt == "J") return;
        //…
        await Task.Delay(0);
    } 
}

public class ListAdapter : ArrayAdapter
{
    //...
    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View v = convertView;
        if (v == null)
        {
            LayoutInflater inflater = (LayoutInflater)Context.GetSystemService(Context.LayoutInflaterService);
            v = inflater.Inflate(Resource.Layout.List, parent, false);
        }
        //...
        v.FindViewById<ImageView>(Resource.Id.typeImageView).SetImageResource(Resource.Drawable.Icon);
        v.FindViewById<TextView>(Resource.Id.numberTextView).Text = Geraetelist[position].geraeteplatz;
        v.FindViewById<TextView>(Resource.Id.descriptionTextView).Text = Geraetelist[position].geraeteinformation;
        ImageView iv = v.FindViewById<ImageView>(Resource.Id.bspImageView);
        iv.SetImageResource(Geraetelist[position].bespielt == "N" ? Resource.Drawable.greenPoint : Resource.Drawable.redPoint);
        //…
        return v;        
    }
}

谁能给我一个简短的提示之类的？我怎样才能为点击的每个项目实现这样的进度条？^^ 如果有任何帮助，我将非常高兴。

预先感谢您的每一个回答，

此致

Answer 1

很明显，您缺少一些有关 ListView 的知识。这个 Xamarin university course 有一些示例和一个解释不同组件的视频。

但基本上，您可以将 background progress bar 作为 View 放在 row AXML 布局文件中，并根据 Progress 属性，那个视图可以改变宽度。

如果您有任何问题，请告诉我

Answer 2

Is it possible, that if one clicks on one of these items, a progress bar is shown which loads smoothly in a certain time interval (lets say 30 seconds) from left to right?

如果你想在点击Listview项时显示进度条，我给你做了一个例子，你可以看看：

1.Declare ListView 布局

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

<ListView
    android:minWidth="25px"
    android:minHeight="25px"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/ListView" />

</LinearLayout>

2.Declare 列表行布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:id="@+id/textView1" 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" />

<ProgressBar android:id="@+id/progressBar1" 
             android:layout_width="match_parent" 
             android:layout_height="wrap_content" 
             android:layout_centerHorizontal="true" android:visibility="invisible"

            style="@android:style/Widget.ProgressBar.Horizontal" />
</LinearLayout>

3.Define 列表视图适配器

public class Post
{      
    public string title { get; set; }
    public bool isselect { get; set; }
   
}

public class CusotmListAdapter : BaseAdapter<Post>
{
    Activity context;
    List<Post> list;

    public CusotmListAdapter(Activity _context, List<Post> _list)
    : base()
    {
        this.context = _context;
        this.list = _list;
    }

    public override Post this[int position]
    {
        get { return list[position]; }

    }

    public override int Count
    {
        get { return list.Count; }

    }

    public override long GetItemId(int position)
    {
        return position;

    }

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View view = convertView;

        // re-use an existing view, if one is available
        // otherwise create a new one
        if (view == null)
            view = context.LayoutInflater.Inflate(Resource.Layout.ListItemRow, parent, false);

        Post item = this[position];
        view.FindViewById<TextView>(Resource.Id.textView1).Text = item.title;
        if(item.isselect==true)
        {
            view.FindViewById<ProgressBar>(Resource.Id.progressBar1).Visibility = ViewStates.Visible;
        }
        else
        {
            view.FindViewById<ProgressBar>(Resource.Id.progressBar1).Visibility = ViewStates.Invisible;
        }


        return view;
    }

}

4.Setting 列表视图适配器

    public class MainActivity : AppCompatActivity
     {
       private ListView listview;
       List<Post> posts = new List<Post>();
       private CusotmListAdapter adapter;
       private int oldposition = -1;
       protected override void OnCreate(Bundle savedInstanceState)
       {
        base.OnCreate(savedInstanceState);
        // Set our view from the "main" layout resource

        posts.Add(new Post() { title = "title 1", isselect = false });
        posts.Add(new Post() { title = "title 2", isselect = false });
        posts.Add(new Post() { title = "title 3", isselect = false });
        posts.Add(new Post() { title = "title 4", isselect = false });
        posts.Add(new Post() { title = "title 5", isselect = false });
        posts.Add(new Post() { title = "title 6", isselect = false });
        posts.Add(new Post() { title = "title 7", isselect = false });
        posts.Add(new Post() { title = "title 8", isselect = false });
        SetContentView(Resource.Layout.activity_main);
        listview = FindViewById<ListView>(Resource.Id.ListView);
        listview.ItemClick+= OnListItemClick;
        adapter= new CusotmListAdapter(this, posts);
        listview.Adapter = adapter;
    }

    private void OnListItemClick(object sender, AdapterView.ItemClickEventArgs e)
    {
        if(oldposition!=-1)
        {
            Post p1 = adapter[oldposition];
            p1.isselect = false;
        }
        oldposition = e.Position;
        Post p = adapter[e.Position];
        p.isselect = true;
        adapter.NotifyDataSetChanged();

      }
     }

更新

您可以更改 CusotmListAdapter GetView 事件中的一些代码：

 public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View view = convertView;

        // re-use an existing view, if one is available
        // otherwise create a new one
        if (view == null)
            view = context.LayoutInflater.Inflate(Resource.Layout.ListItemRow, parent, false);

        Post item = this[position];

        view.FindViewById<TextView>(Resource.Id.textView1).Text = item.title;
        ProgressBar p = view.FindViewById<ProgressBar>(Resource.Id.progressBar1);
        p.Max = 100;
        p.Progress = 100;
        //p.IncrementProgressBy(-10);
        if(item.isselect==true)
        {
            view.FindViewById<ProgressBar>(Resource.Id.progressBar1).Visibility = ViewStates.Visible;
            new Thread(new ThreadStart(delegate
            {
                while (p.Progress > 0)
                {
                    p.Progress -= 20;
                    Thread.Sleep(1000);
                }
            })).Start();
        }
        else
        {
            view.FindViewById<ProgressBar>(Resource.Id.progressBar1).Visibility = ViewStates.Invisible;
        }


        return view;
    }

那请看截图：

ListView 项目作为进度条

ListView item as a progress bar

listview

list

listadapter

xamarin.android

progress-bar

更新