单击列表项时如何显示toast

本文关键字：显示 toast 何显示 列表 单击 | 更新日期: 2023-09-27 18:29:32

试图在单击列表项时显示toast，但在Visual studio中显示了许多错误。代码在android工作室中运行良好，我使用RemobjectC#为C#重新制作了它。以下是我的主要活动代码

using System;
using java.util;
using android.app;
using android.content;
using android.os;
using android.util;
using android.view;
using android.widget;
namespace org.me.androidapplication8
{
public class MainActivity: Activity {
    protected override void onCreate(Bundle savedInstanceState) {
        base.onCreate(savedInstanceState);
        ContentView = R.layout.main;
        // Simple array with a list of my favorite TV shows
        String[] favoriteTVShows = {"Pushing Daisies", "Better Off Ted",
                "Twin Peaks", "Freaks and Geeks", "Orphan Black", "Walking Dead",
                "Breaking Bad", "The 400", "Alphas", "Life on Mars"};
        ListAdapter theAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, favoriteTVShows);
        ListView theListView = (ListView)findViewById(R.id.theListView);
        theListView.setAdapter(theAdapter);
        /*ERROR part 
        theListView.setOnItemClickListener(new
                    AdapterView.OnItemClickListener() {
                          public override void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                             String tvShowPicked = "You selected" +
                                     String.valueOf(adapterView.getItemAtPosition(position));
                              Toast.makeText(MainActivity.this, tvShowPicked, Toast.LENGTH_SHORT).show();
                           }
                    });
        */ 
    }
}
}

主布局xml文件的代码

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

我对C#知识不多。请建议我如何在C#上重新制作它，以及为什么我会收到这个错误

这些是的错误

theListView.setOnItemClickListener(new  //Error:- cannot instantiate interface type
 public override void onItemClick(AdapterView<?> adapterView, View view, int position, long id) { //Syntax error Syntax error
    String tvShowPicked = "You selected " + favoriteTVShows[position];//Unknown identifier (position)
    Toast.makeText(MainActivity.this, tvShowPicked, Toast.LENGTH_SHORT).show(); //identifier expected(this)
            }
                    });//Type expected
//(E374) opening parenthesis or less expected, got closing brace
//(E1) semicolon expected, got "public"

...

单击列表项时如何显示toast

theListView.setOnItemClickListener(new
                    AdapterView.OnItemClickListener() {
                          public override void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                             String tvShowPicked = "You selected " + favoriteTVShows[position];
                              Toast.makeText(MainActivity.this, tvShowPicked, Toast.LENGTH_SHORT).show();
                           }
                    });

将其替换为您的代码。

尝试

String tvShowPicked = "You selected"+String.valueOf(theAdapter.getItemAtPosition(position));

而不是

String tvShowPicked = "You selected"+String.valueOf(adapterView.getItemAtPosition(position));

通过将适配器设置为全局适配器或将其设置为最终

问题是在C#中，匿名类型无法实现方法。在这种情况下，您需要使用lambda或实现主类中的方法。

我使用了@AnujSharma的答案，并稍微更改了代码：

theListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
            String tvShowPicked = "You selected " + favouriteTVShows[position];
            Toast.makeText(MainActivity.this, tvShowPicked, Toast.LENGTH_SHORT).show();
        }
    });

代替：

theListView.setOnItemClickListener(new
                AdapterView.OnItemClickListener() {
                      public override void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                         String tvShowPicked = "You selected " + favoriteTVShows[position];
                          Toast.makeText(MainActivity.this, tvShowPicked, Toast.LENGTH_SHORT).show();
                       }
                });
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