Question

我想执行文件下载并显示对话框。但是，当我尝试显示对话框时，我收到错误，有什么帮助吗？

问题出在showDialog(DIALOG_DOWNLOAD_PROGRESS);

以下是错误消息：不推荐使用类型为Activity的showDialog（int）方法

继承我的代码：

public class download extends Activity {

public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    startBtn = (Button)findViewById(R.id.startBtn);
    startBtn.setOnClickListener(new OnClickListener(){
        public void onClick(View v) {
            startDownload();
        }
    });
}

private void startDownload() {
    String url = "http://practicalbuddhist.com/wp-content/uploads/2012/03/Synapses-Image-for-March-17-2010-Blog-Entry.jpg";
    new DownloadFileAsync().execute(url);
}
@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case DIALOG_DOWNLOAD_PROGRESS:
        mProgressDialog = new ProgressDialog(this);
        mProgressDialog.setMessage("Running Download Test...");
        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        mProgressDialog.setCancelable(false);
        mProgressDialog.show();
        return mProgressDialog;
    default:
        return null;
    }
}

类DownloadFileAsync扩展了AsyncTask {

@SuppressWarnings("deprecation")
@Override
protected void onPreExecute() {
    super.onPreExecute();
    showDialog(DIALOG_DOWNLOAD_PROGRESS);

}

@Override
protected String doInBackground(String... aurl) {
    int count;

try {

URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();

int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);

InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream("/sdcard/Downloadtest.jpg");

byte data[] = new byte[1024];

long total = 0;

    while ((count = input.read(data)) != -1) {
        total += count;
        publishProgress(""+(int)((total*100)/lenghtOfFile));
        output.write(data, 0, count);
    }

    output.flush();
    output.close();
    input.close();
} catch (Exception e) {}
return null;

}
protected void onProgressUpdate(String... progress) {
     Log.d("ANDRO_ASYNC",progress[0]);
     mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}

@SuppressWarnings("deprecation")
@Override
protected void onPostExecute(String unused) {
    dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}

} }

Answer 1

以下是错误消息：不推荐使用类型为Activity的showDialog（int）方法

这是一个警告，而不是错误。您可以升级到使用Fragments或忽略它。

Answer 2

您还可以使用未被删除的ProgressDialog和show（）方法，而不是使用showDialog。在AsyncTask中声明对话框：

class DownloadFileAsync extends AsyncTask<String, String, String> {

private ProgressDialog pDialog;


    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
        pDialog = new ProgressDialog(context);
        pDialog.setMessage("Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }
}

并在onPostExecute（）中使用

pDialog.dismiss();

下载文件进度对话框

2 个答案: