Question

当用户在搜索视图中搜索并且没有找到文件时，我想向用户显示一条消息，然后在文本视图中显示此消息。未找到文件，我该怎么做。搜索代码是完美的工作，但是如果用户搜索列表视图中不可用的内容，然后显示未找到消息，我想这样做。

我的搜索代码

 public  void filter(String chartext)
{
    chartext= chartext.toLowerCase(Locale.getDefault());
    heroList.clear();
    if(chartext.length()==0)
    {
        heroList.addAll(arrayList);
    }
    else
    {
        for(Pdf pdf : arrayList)
        {
            if(pdf.getName().toLowerCase(Locale.getDefault()).contains(chartext))
            {
                heroList.add(pdf);

            }
        }
    }
    notifyDataSetChanged();
}

适配器代码

    public class PdfAdapter extends BaseAdapter
{
  List<Pdf> heroList;
        //activity context
    LayoutInflater inflater;
        Context mcontext;
    ArrayList<Pdf>arrayList;
        //the layout resource file for the list items


    public interface OnItemClickListener{
        void onItemClick(int position);
    }
    private OnItemClickListener mOnItemClickListener;

    //constructor initializing the values
    public PdfAdapter(Context context, List<Pdf> pdfList,OnItemClickListener mOnItemClickListener) {
        this.mcontext = context;
        this.heroList = pdfList;
        inflater = LayoutInflater.from(mcontext);
        this.arrayList= new ArrayList<Pdf>();
        this.arrayList.addAll(pdfList);
        this.mOnItemClickListener =mOnItemClickListener;
    //    mOnItemClickListener = listener;
    }

    @Override
    public int getCount() {
        return heroList.size();
    }

    @Override
    public Object getItem(int i) {
        return heroList.get(i);
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(final int position, View convertView,  ViewGroup parent) {

        ViewHolder holder;
        if(convertView==null) {
            holder = new ViewHolder();
            convertView = inflater.inflate(R.layout.list_layout, null);

            // LayoutInflater layoutInflater = LayoutInflater.from(context);

            //  Typeface custom_font = Typeface.createFromAsset(getContext().getAssets(),"DroidSans-Bold.ttf");
            holder.textViewName = convertView.findViewById(R.id.textViewName);
            holder.textViewurl = convertView.findViewById(R.id.textViewUrl);
           holder.download = convertView.findViewById(R.id.downloadimage);
            //   textViewName.setTypeface(custom_font);
            //  Button buttonpass = view.findViewById(R.id.password);
            convertView.setTag(holder);
        }
        else
        {
            holder=(ViewHolder)convertView.getTag();
        }
      //  Pdf hero = heroList.get(position);


      holder.textViewName.setText(heroList.get(position).getName());
      holder.textViewurl.setText(heroList.get(position).getUrl());
       holder.download.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mOnItemClickListener.onItemClick(position);
            }
        });
        return convertView;

    }

    public  class ViewHolder
    {
        TextView textViewName,textViewurl,note;
        ImageView download;
    }

    public  void filter(String chartext)
    {
        chartext= chartext.toLowerCase(Locale.getDefault());
        heroList.clear();
        if(chartext.length()==0)
        {
            heroList.addAll(arrayList);
        }
        else
        {
            for(Pdf pdf : arrayList)
            {
                if(pdf.getName().toLowerCase(Locale.getDefault()).contains(chartext))
                {
                    heroList.add(pdf);

                }
            }

        }
        notifyDataSetChanged();
    }


}

Answer 1

您可以使用名为“ Toast”的组件，here you can find the guidelines。

吐司可在一个小弹出窗口中提供有关操作的简单反馈。它仅填充消息所需的空间量，并且当前活动保持可见和交互式。超时后，吐司自动消失。

一个吐司的例子：

Context context = getApplicationContext();
CharSequence text = "No file found!";
int duration = Toast.LENGTH_SHORT;

Toast toast = Toast.makeText(context, text, duration);
toast.show();

您可以像这样压缩所有内容：

Toast.makeText(getApplicationContext(),"No file found!",Toast.LENGTH_SHORT).show();

因此在您的应用程序中将如下所示：

if (heroList.size() == 0) {
    Toast.makeText(getApplicationContext(),"No file found!",Toast.LENGTH_SHORT).show();
}

文件不匹配时如何显示消息

1 个答案: