如何根据动态列表创建不断变化的按钮数？

Question

为了澄清，我有一个列表，根据员工执行的工作数量而变化。我想在Android应用程序中创建一个页面，其中列表中的每个作业都有一个按钮，列表将增加和减少作业数量。我想以一种允许我改变按钮颜色和边距的方式来做，但我还没找到方法。

Answer 1

我打算假设您将此标记为C＃和Android，您正在使用Xamarin。我相信实现目标的最佳方法是动态创建按钮。

从一个空白的Android解决方案开始，我做了以下更改：

Main.axml

在主布局视图中添加了id“contentLayout”。

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

MainActivity

创建一个基本的Job类，并按“优先级”设置背景颜色，作为该过程如何工作的示例。

using Android.App;
using Android.Widget;
using Android.OS;
using Android.Views;
using System.Collections.Generic;
using Android.Content;

namespace App1
{
    [Activity(Label = "App1", MainLauncher = true, Icon = "@drawable/icon")]
    public class MainActivity : Activity
    {
        private LinearLayout _contentLayout;
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            SetContentView(Resource.Layout.Main);

            _contentLayout = FindViewById<LinearLayout>(Resource.Id.contentLayout);

            List<MyJob> jobs = GetJobs();
            _contentLayout.AddView(GetButtons(this, jobs));
        }

        private List<MyJob> GetJobs()
        {
            return new List<MyJob>()
                   {
                       new MyJob() { Text = "First Job", Priority = MyJob.PriorityEnum.Low },
                       new MyJob() { Text = "Second Job", Priority = MyJob.PriorityEnum.Medium },
                       new MyJob() { Text = "Third Job", Priority = MyJob.PriorityEnum.High },
                       new MyJob() { Text = "Fourth Job", Priority = MyJob.PriorityEnum.Low },
                   };
        }

        private ViewGroup GetButtons(Context context, List<MyJob> jobs)
        {
            if (jobs == null || jobs.Count == 0)
            {
                return null;
            }

            LinearLayout buttonLayout = new LinearLayout(context)
                                        {
                                            Orientation = Orientation.Vertical,
                                            LayoutParameters = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MatchParent, ViewGroup.LayoutParams.WrapContent)
                                        };

            foreach (MyJob job in jobs)
            {
                Button button = new Button(context)
                                {
                                    LayoutParameters = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MatchParent, ViewGroup.LayoutParams.WrapContent),
                                    Text = job.Text,
                                };

                button.SetBackgroundColor(GetButtonColor(job.Priority));

                buttonLayout.AddView(button);
            }

            return buttonLayout;
        }

        private Android.Graphics.Color GetButtonColor(MyJob.PriorityEnum priority)
        {
            switch (priority)
            {
                case MyJob.PriorityEnum.High:
                    return new Android.Graphics.Color(255, 0, 0);
                case MyJob.PriorityEnum.Medium:
                    return new Android.Graphics.Color(255, 255, 0);
                case MyJob.PriorityEnum.Low:
                default:
                    return new Android.Graphics.Color(0, 255, 0);
            }
        }
    }

    internal class MyJob
    {
        public enum PriorityEnum { Low, Medium, High }
        public string Text { get; set; }
        public PriorityEnum Priority { get; set; }
    }
}

输出

Screen grab of final output - 它需要一些工作，但我相信这会让你朝着正确的方向前进。