View Holder 稳定性问题

Question

我正在向服务器上传数据，如果数据成功上传到服务器，那么我会显示 "Saved"，就像你可以看到 "Uploaded" 的图像。

但问题是，我为第一个项目行存储了数据，而在不同的行项目中获取 "Saved" 文本

holder.textDataStatus.setText(ImageList.get(position).getData());

protected void onPostExecute(String file_url) {
  // dismiss the dialog once product deleted
  pDialog.dismiss();

  try {

       // Prepare Save Data
       if(strStatusId.equals("0"))
       {
              Toast.makeText(UploadImagesActivity.this, "Unable to upload", Toast.LENGTH_SHORT).show();
                }
                else if (strStatusId.equals("1"))
                {
                    Toast.makeText(UploadImagesActivity.this, "Data Uploaded Successfully", Toast.LENGTH_SHORT).show();
                    ImageList.get(position).setData("Saved");               
                    Log.d("strData:", fileName); // getting correct tapped item
                    mAdapter.notifyDataSetChanged();
                }
                else
                {
                    Toast.makeText(UploadImagesActivity.this, "Unable to upload", Toast.LENGTH_SHORT).show();
                }

                } catch (Exception e) {
                    // TODO: handle exception
                }


           if (file_url != null){
                Toast.makeText(UploadImagesActivity.this, file_url, Toast.LENGTH_LONG).show();
           }

Answer 1

尝试包括

    public View getView(final int position, View convertView,
                    ViewGroup parent) {
                // Avoid unneccessary calls to findViewById() on each row, which is
                // expensive!

                holder = null;
     int crntposition = position;

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

                    // Create a ViewHolder and store references to the children
                    // views
                    holder.textName = (TextView) convertView
                            .findViewById(R.id.textName);
                    holder.thumbnail = (ImageView) convertView
                            .findViewById(R.id.thumbnail);                
                    holder.textStatus = (TextView) convertView
                            .findViewById(R.id.textStatus);
                    holder.textDataStatus = (TextView) convertView
                            .findViewById(R.id.textDataStatus);
                    holder.btnUpload = (Button) convertView
                            .findViewById(R.id.btnUpload);
                    holder.btnData = (Button) convertView
                            .findViewById(R.id.btnData);

                    // The tag can be any Object, this just happens to be the
                    // ViewHolder
                   convertView.setTag(holder);
            convertView.setTag(R.id.textDataStatus, holder.textDataStatus);

                holder.textDataStatus.setTag(crntposition);
                } else {
                    holder = (ViewHolder) convertView.getTag();
                }

                holder.btnUpload.setEnabled(ImageList.get(position)
                        .isStatusEnable());            
                holder.textStatus.setText(ImageList.get(position).getMessage());
                holder.textDataStatus.setText(ImageList.get(Integer.parseInt(holder.textDataStatus.getTag().toString())).getData());
                strPath = ImageList.get(crntposition)).getImages().toString();
 Log.e("IMAGE CLICK",strPath);


                // Get File Name
                fileName = strPath.substring(strPath.lastIndexOf('/') + 1, strPath.length());            

                holder.btnData.setOnClickListener(new OnClickListener() {

                    @SuppressWarnings("deprecation")
                    @Override
                    public void onClick(View v) {
                        // TODO Auto-generated method stub
                        strPath = ImageList.get(position).getImages().toString();
                        fileName = strPath.substring(strPath.lastIndexOf('/') + 1, strPath.length());                                      

                        showDialog(DIALOG_DATA);

                    }
                });


                return convertView;

            }
        }

..在适配器 class

的 getView 方法中初始化 holder.textDataStatus 之后

Answer 2

问题是您的适配器不知道将哪一行的数据上传到服务器。你需要告诉你的适配器。至于问题"How to tell that to adapter?"，你已经有了一个列表ImageList。我们只需要对其进行编辑。

现在，向您的 MyData class 添加另一个布尔值，例如：boolean uploaded = false; 并为其创建 getter setter。

将以下行添加到您的 getView():

if(ImageList.get(position).isUploaded()){
    holder.btnUpload.setText("Save");
}else{
    holder.btnUpload.setText("Upload");
}

现在，我们需要在上传完成后将此值设置为 true。我们应该只从 UploadData class 开始。为此，我们需要将位置发送到 UploadData class。我们可以通过构造函数来做到这一点，如下所示：

class UploadData extends AsyncTask<String, String, String> {
    private ProgressDialog pDialog;

    int position;

    //constructor to pass position of row, on which button was clicked to class
    public UploadData(int position){
        this.position=position;
    }

     /**
    * Before starting background thread Show Progress Dialog
    * */

    .
    .
    .
    .

   protected void onPostExecute(String file_url) {
       // dismiss the dialog once product deleted
       pDialog.dismiss();

       //after upload is done, set value to true
       ImageList.get(position).setUploaded(true);
       //now we need to notify our adapter so that it can reflect changes
       mAdapter.notifyDataSetChanged();
    .
    .

现在，根据您当前的代码，我认为通过构造函数将 position 的值传递给 UploadData 对您来说真的很难。因此，您可以尝试在 class.

中的全局变量中设置一个值

编辑 1：

将位置传递给 holder.btnData.SetOnClickListener 中的全局变量，如下所示：

holder.btnData.setOnClickListener(new OnClickListener() {

            @SuppressWarnings("deprecation")
            @Override
            public void onClick(View v) {
                //pass position into activity's global variable
                pos = position/*position from adapter*/;
                strPath = ImageList.get(position).getImages().toString();
                fileName = strPath.substring(strPath.lastIndexOf('/') + 1, strPath.length());                                      

                showDialog(DIALOG_DATA);

            }
        });

如果您需要任何解释，请发表评论。

Answer 3

尝试修改 getView(...)，检查 //added codes。重点是点击按钮时如何获取项目位置：

@Override
public View getView(int position, View convertView,
            ViewGroup parent) {
        // Avoid unneccessary calls to findViewById() on each row, which is
        // expensive!

        holder = null;

        if (convertView == null) {

            ... ...             


        } else {
            holder = (ViewHolder) convertView.getTag();
        }

         //added codes
         holder.btnUpload.setTag(new Integer(position));    
         holder.btnData.setTag(new Integer(position));


        ... ...            

        // btnUpload
        holder.btnUpload.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // Upload     

                //if you need position here, get it by:
                //added codes
                //Button clickBtn = (Button)v;
                //int position = ((Integer)clickBtn.getTag()).intValue();          
                  ..........
            }
        });


        holder.btnData.setOnClickListener(new OnClickListener() {

            @SuppressWarnings("deprecation")
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                //added codes
                Button clickBtn = (Button)v;
                int position = ((Integer)clickBtn.getTag()).intValue();

                strPath = ImageList.get(position).getImages().toString();
                fileName = strPath.substring(strPath.lastIndexOf('/') + 1, strPath.length());                                      

                showDialog(DIALOG_DATA);

            }
        });

        if(ImageList.get(position).isUploaded()){
            holder.textDataStatus.setText("Saved");
        }else{
            holder.textDataStatus.setText("");
        }


        return convertView;

    }

希望对您有所帮助！

View Holder 稳定性问题

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