上传时未显示异步任务中的 ProgressBar [英] ProgressBar in asynctask is not showing on upload
问题描述
谁能告诉我，为什么上传图片时进度条不显示.我从我的旧项目中复制了 asynctask 结构.在我的旧项目中，我使用 asynctask 从网络服务器下载图片，并在下载时显示进度条.这是我的代码:
Can someone tell me, why progressbar isnt showing when picture is being uploaded. I copied asynctask structure from my old project where it works. In my old project i use asynctask to download pictures from web server, and to show progressbar while downloading. Here is my code:
public class PreviewPostActivity extends Activity {
ImageView imageView;
TextView tvComment;
Button submit;
MyLocationListener locationListener;
List<NameValuePair> list = new ArrayList<NameValuePair>();
private final String url = "***"; //Url of php script
ProgressDialog pDialog;
String responseMessage="";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.preview_post);
Intent intent = this.getIntent();
imageView = (ImageView)findViewById(R.id.imgPerview);
tvComment = (TextView)findViewById(R.id.txtPreviewComment);
submit = (Button)findViewById(R.id.btnPreviewSubmit);
Bitmap image = (Bitmap)intent.getParcelableExtra("picture");
String comment = intent.getStringExtra("comment");
locationListener = (MyLocationListener)intent.getSerializableExtra("location");
String imagePath = intent.getStringExtra("imagePath");
String date = intent.getStringExtra("date");
imageView.setImageBitmap(image);
tvComment.setText(comment);
//tvComment.append("
"+locationListener.latitude + "
"+locationListener.longitude);
list.add(new BasicNameValuePair("image", imagePath));
list.add(new BasicNameValuePair("comment", comment));
list.add(new BasicNameValuePair("longitude", Double.toString(locationListener.longitude)));
list.add(new BasicNameValuePair("latitude", Double.toString(locationListener.latitude)));
list.add(new BasicNameValuePair("date", date));
submit.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new uploadPost().execute();
}
});
}
public void post(List<NameValuePair> nameValuePairs) {
HttpParams httpParameters = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParameters, 100000);
HttpConnectionParams.setSoTimeout(httpParameters, 200000);
HttpClient httpClient = new DefaultHttpClient(httpParameters);
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url);
try {
MultipartEntity entity = new MultipartEntity();
for(int index=0; index < nameValuePairs.size(); index++) {
if(nameValuePairs.get(index).getName().equalsIgnoreCase("image")) {
// If the key equals to "image", we use FileBody to transfer the data
entity.addPart(nameValuePairs.get(index).getName(), new FileBody(new File(nameValuePairs.get(index).getValue()),"image/jpeg"));
} else {
// Normal string data
entity.addPart(nameValuePairs.get(index).getName(), new StringBody(nameValuePairs.get(index).getValue()));
}
}
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost, localContext);
HttpEntity httpEntity = response.getEntity();
String responseMessage = EntityUtils.toString(httpEntity);
tvComment.setText(responseMessage);
} catch (IOException e) {
e.printStackTrace();
}
}
class uploadPost extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(PreviewPostActivity.this);
pDialog.setMessage("Uploading post. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
//post(list);
HttpParams httpParameters = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParameters, 100000);
HttpConnectionParams.setSoTimeout(httpParameters, 200000);
HttpClient httpClient = new DefaultHttpClient(httpParameters);
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url);
try {
MultipartEntity entity = new MultipartEntity();
for(int index=0; index < list.size(); index++) {
if(list.get(index).getName().equalsIgnoreCase("image")) {
// If the key equals to "image", we use FileBody to transfer the data
entity.addPart(list.get(index).getName(), new FileBody(new File(list.get(index).getValue()),"image/jpeg"));
} else {
// Normal string data
entity.addPart(list.get(index).getName(), new StringBody(list.get(index).getValue()));
}
}
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost, localContext);
HttpEntity httpEntity = response.getEntity();
responseMessage = EntityUtils.toString(httpEntity);
//tvComment.setText(responseMessage);
} catch (IOException e) {
e.printStackTrace();
}
}
});
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
tvComment.setText(responseMessage);
pDialog.dismiss();
}
}
因此，当我点击上传按钮时，屏幕冻结并保持冻结状态直到上传完成，并且根本不显示进度条.有时它显示，但它的后方，我不知道为什么.我曾尝试从 doInBackground 主体插入整个代码的类中调用 Post() 方法(主体中的代码与 post() 方法中的代码相同)但效果是相同的，所以我想我在创建进度条时没有做正确的事情.但是我再次说我从旧项目中复制了整个异步任务代码，它工作正常.
So when i hit button for upload, screen freezes and stay frozen until upload is complete, and progress bar isnt showing at all. Sometimes it shows, but its rly rear and i dont know why. I have tried calling Post() method from class in doInBackground body insted of whole code (code in body is the same as in post() method) but effect is the same, so i guess i didnt do something right in creating progressbar. But again i say i copied whole asynctask code from old project in witch it worked fine.
我只是尝试在 PreviewPostActivity.class 的构造函数中创建进度条，然后我为 asynctask 类创建了构造函数，但它仍然不起作用.我很困惑，因为它在我的旧程序中有效.这是他的代码:
I just tryed creating progress bar in constructor of PreviewPostActivity.class and after that i made constructor for asynctask class but it still dosent work. I am rly confused becouse it worked in my old program. Here is code from him:
class GetSlike extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(KlubSlikeActivity.this);
pDialog.setMessage("Ucitavanje u toku. Molimo vas sacekajte...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
String id = Integer.toString(k.getId());
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("klub",id));
slikeUrl = JSONAdapter.getSlike(params);
gv.setAdapter(new SlikeAdapter(slikeUrl,KlubSlikeActivity.this));
}
});
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
唯一改变的是 doInBackground body...
Only thing changed is doInBackground body...
已
执行runOnUiThread()后显示对话框.
推荐答案
Run on ui thread in asynctask doinbackground() 不正确.此外，您在 doInBackground() 中返回 null，并且在 onPostExecute() 中有参数 file_url.doInbackground() 中的返回值在 onPostExecute() 中接收值.
Run on ui thread in asynctask doinbackground() is not correct. Also you are returning null in doInBackground() and you have parameter file_url in onPostExecute(). Return value in doInbackground() recieve value in onPostExecute().
doInBackGround() 在后台运行，因此您无法在此处访问或更新 ui.
doInBackGround() runs in background so you cannot access or update ui here.
要更新用户界面，您可以使用 onPostExecute().
To update ui you can use onPostExecute().
您的 AsyncTask 应该如下所示.你做错了.
Your AsyncTask should be something like below. You are doing it the wrong way.
http://developer.android.com/reference/android/os/异步任务.html.查看 4 个步骤下的主题
pd= new ProgressDialog(this);
pd.setTitle("Posting data");
new PostTask().execute();
private class PostTask extends AsyncTask<VOid, Void, Void> {
protected void onPreExecute()
{//display dialog.
pd.show();
}
protected SoapObject doInBackground(Void... params) {
// TODO Auto-generated method stub
//post request. do not update ui here. runs in background
return null;
}
protected void onPostExecute(Void param)
{
pd.dismiss();
//update ui here
}
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