Question

我正在使用AsyncTask从服务器下载大量数据，我的AsyncTask工作正常，所以我添加了一个进度条，使一切都很美，但问题是当它的运行进度条冻结一半时，并且我使用进度对话框，它也冻结了一半，

private class downloadChannelsfromserver extends
        AsyncTask<String, Void, String> {

     ProgressDialog progressDialog;

    @Override
    protected String doInBackground(String... url) {
        String data = "";

        try {
            // Fetching the data from web service
            data = getLinksfromServer(url[0]);
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
        }
        return data;
    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
         progressDialog= ProgressDialog.show(Settings.this, "Synchronicing","Synchronicing", true);


    }



    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        JSONObject json;
        try {
            json = new JSONObject(result);
            db.deleteAll();
            final JSONArray jsonArray = json.getJSONArray("XXXX");

            for (int i = 0; i < jsonArray.length(); i++) {
                                ///use for insert datainto database
            }
            finish();

            progressDialog.dismiss();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            Log.e("settings", "", e);
            progressDialog.dismiss();

        }
    }

能和某人告诉我为什么会这样，Pls

Answer 1

请遵循此代码

private ProgressDialog pdialog = null;

@Override
protected void onPreExecute() { 
   super.onPreExecute();

   if(pdialog ==null){
     //display progress dialog like this
     pdialog = new ProgressDialog(context);
     pdialog.setCancelable(false);
     pdialog.setMessage("Please Wait...");
     pdialog.show();
   }
}



@Override
   protected void onPostExecute(Boolean result) {
        super.onPostExecute(result);
        //dismiss progress dialog like this

        if(pdialog!=null){
             pdialog.dismiss();
             pdialog = null;
        }
    }

Answer 2

进度条被卡住的原因是我的JSON解码，因为onPostExecute属于UI线程需要几次解码json结果。因此它将冻结UI直到JSON解码，因此将解码部分移动到doInBackground将解决UI冻结问题，因为doInBackground属于后台线程

Answer 3

请编辑您的代码：

private class downloadChannelsfromserver extends
    AsyncTask<String, Void, String> {

 ProgressDialog progressDialog;

public downloadChannelsfromserver()
{
    progressDialog = new ProgressDialog(Settings.this);
    progressDialog.setTitle("Synchronicing ...");
    progressDialog.setCancelable(false);
    progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
}

@Override
protected String doInBackground(String... url) {
    String data = "";

    try {
        // Fetching the data from web service
        data = getLinksfromServer(url[0]);
    } catch (Exception e) {
        Log.d("Background Task", e.toString());
    }
    return data;
}

@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub
    //super.onPreExecute();
  progressDialog.show();

}



@Override
protected void onPostExecute(String result) {
    // TODO Auto-generated method stub
    super.onPostExecute(result);
    JSONObject json;
    try {
        json = new JSONObject(result);
        db.deleteAll();
        final JSONArray jsonArray = json.getJSONArray("XXXX");

        for (int i = 0; i < jsonArray.length(); i++) {
                            ///use for insert datainto database
        }
        finish();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        Log.e("settings", "", e);
    }
    finally
    {
     progressDialog.dismiss();
    }
}

我希望这会有所帮助。

Answer 4

只需使用此代码：

runOnUiThread(object : Runnable {
    override fun run() {
        pausingDialog =
            SweetAlertDialog(this@History_Activity, SweetAlertDialog.PROGRESS_TYPE)
        pausingDialog!!.titleText = "Please wait...."
        pausingDialog!!.setCancelable(false)
        pausingDialog!!.show()
    }
})

runOnUiThread(object : Runnable {
    override fun run() {
    }
})

Progressbar在AsyncTask中不起作用

4 个答案: