android - 我想要一个进度条，但得到一个微调进度对话框

Question

我正在使用公共(public) AsynTask 下载数据，我正在尝试显示一个进度条来显示下载进度。我想我的代码是正确的，但我得到的只是一个微调进度对话框。我错过了什么吗？为什么进度条不显示？这是代码。 感谢您的指点。

public class FileDownloader extends AsyncTask<String, Integer, Void>
{
private Context _appContext;
private HttpURLConnection _urlConn;
private ProgressDialog _progressDia = null;
private DialogInterface.OnCancelListener _progDiaCancelListener = new DialogInterface.OnCancelListener()
{
    /**
     * When the progress dialog is canceled, stop the GET request.
     */
    public void onCancel(DialogInterface dialog) 
    {
        FileDownloader.this.cancel(true);
    }
};

/**
 * Constructor.
 * @param appContext
 */
public FileDownloader(Context appContext)
{
    _appContext = appContext;
    _progressDia = new ProgressDialog(_appContext, ProgressDialog.STYLE_HORIZONTAL);
    _progressDia.setMax(100);
    _progressDia.setTitle(_appContext.getString(R.string.diaHeader1));
    _progressDia.setMessage(_appContext.getString(R.string.diaBody1));
    _progressDia.setCancelable(true);
    _progressDia.setIndeterminate(false);
    _progressDia.setOnCancelListener(_progDiaCancelListener);
}

// Runs on the UI thread
@Override
protected void onPreExecute() 
{
         _progressDia.setProgress(0);
         _progressDia.show();                           
}

@Override
protected Void doInBackground(String... args) 
{
    String dloadURL = args[0],
           saveLoc = args[1];
            ...
            ...
        while((len = input.read(buf)) > 0)
        {
            output.write(buf, 0, len);
            total += len;
            publishProgress((int)total * 100/lenghtOfFile);
        }
            ...
            ...
    }
    catch(SocketTimeoutException ex)
    {   
    }
    finally
    {
         ...
}

// This is executed on main UI thread.
@Override
protected void onProgressUpdate(Integer... values) 
{
     _progressDia.setProgress(values[0]);
}

@Override
protected void onCancelled() 
{
         ...
}

// This is executed on main UI thread.
@Override
protected void onPostExecute(Void result) 
{
        removeProgressDialog();
        ...
}

    /**
     * Remove the message dialog, if still showing.
     */
    private void removeProgressDialog()
    {
        if(_progressDia != null && _progressDia.isShowing())
        _progressDia.dismiss();
    }
}

Answer 1

可能您忘记设置 dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

看看这个对我有用的示例代码:

ProgressDialog dialog;

@Override
protected void onPreExecute() {
    dialog = new ProgressDialog(this);
    dialog.setMessage("Matching progress");
    dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    dialog.setMax(100);
    dialog.setCancelable(false);
    dialog.show();
}

/*
 * (non-Javadoc)
 * @see android.os.AsyncTask#doInBackground(Params[])
 */
@Override
protected Void doInBackground(Void... params) {

    return null;

}

protected void onPostExecute(Void result) {
    dialog.hide();
    dialog = null;
}