执行 doInBackground() 时，如何在 android 中显示进度微调器
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How to show a progress spinner in android, when doInBackground() is being executed
提问by Archie.bpgc
This is my Activity class where i use AsyncTask to get data from a server:
这是我的 Activity 类，我使用 AsyncTask 从服务器获取数据：
public class UserProfileActivity extends Activity {
private ImageView userImage;
private TextView userName;
private TextView userLocation;
private TextView editInfo;
private TextView chnageImage;
private TextView userScore;
private ListView friendsList;
public ArrayAdapter<String> adapter;
public int score;
public int level;
public String image;
public String fname;
public String lname;
public String city;
public int id;
public String email;
protected Activity activity = this;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.user_profile);
userImage = (ImageView) findViewById(R.id.profileImage);
userName = (TextView) findViewById(R.id.userName_profile);
userLocation = (TextView) findViewById(R.id.userLocation_profile);
editInfo = (TextView) findViewById(R.id.edit_profile);
chnageImage = (TextView) findViewById(R.id.changeImage_profile);
userScore = (TextView) findViewById(R.id.userScore_profile);
friendsList = (ListView) findViewById(R.id.friendsList);
new LongOperation().execute("");
}
private class LongOperation extends AsyncTask<String, Void, String> {
private InputStream is;
private StringBuilder sb;
private String result;
@Override
protected String doInBackground(String... params) {
try {
HttpPost httppost = new HttpPost(
"http://www.xxxxxxxxx.com/mobile/getProfileInfo");
HttpResponse response = SignUpActivity.httpclient
.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"), 8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line = "0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
}
try {
JSONObject jObj = new JSONObject(result);
String status = jObj.getString("status");
score = jObj.getInt("credits");
level = jObj.getInt("level");
image = jObj.getString("image");
fname = jObj.getString("fname");
lname = jObj.getString("lname");
city = jObj.getString("city");
id = jObj.getInt("user_id");
email = jObj.getString("email");
JSONArray friendsJsonArray = jObj.getJSONArray("friends");
int size = friendsJsonArray.length();
ArrayList<String> friendsNames = new ArrayList<String>();
String[] friendsIds = new String[size];
for (int i = 0; i < size; i++) {
friendsNames.add(friendsJsonArray.getJSONObject(i)
.getString("name"));
}
adapter = new ArrayAdapter<String>(getApplicationContext(),
R.layout.simple_listview_item, friendsNames);
} catch (Exception e) {
}
} catch (Exception e) {
}
return "Executed";
}
@Override
protected void onPostExecute(String result) {
friendsList.setAdapter(adapter);
userScore.setText(score + " points" + " level " + level);
userName.setText(fname + " " + lname);
userLocation.setText(city);
Bitmap bitmap = null;
try {
bitmap = BitmapFactory
.decodeStream((InputStream) new URL(image).getContent());
} catch (MalformedURLException e1) {
e1.printStackTrace();
} catch (IOException e2) {
e2.printStackTrace();
}
userImage.setImageBitmap(bitmap);
}
@Override
protected void onPreExecute() {
}
@Override
protected void onProgressUpdate(Void... values) {
}
}
}
when this activity is loaded it shows all the default values and images and then changes when background code execution is competed(as excepted), but this takes 2-3 secs for which user will be seeing default values, which i dont want to. So how can i keep a spinner like this:
加载此活动时，它会显示所有默认值和图像，然后在完成后台代码执行时更改（除外），但这需要 2-3 秒，用户将看到默认值，我不想看到。那么我怎样才能保持这样的旋转器：
for 2-3 secs and then when the spinner disappears the activity must show the actual values.
2-3 秒，然后当微调器消失时，活动必须显示实际值。
Thank you
谢谢
回答by Nirali
Refer the below code
参考下面的代码
private class FetchRSSFeeds extends AsyncTask<String, Void, Boolean> {
private ProgressDialog dialog = new ProgressDialog(HomeActivity.this);
/** progress dialog to show user that the backup is processing. */
/** application context. */
@Override
protected void onPreExecute() {
this.dialog.setMessage("Please wait");
this.dialog.show();
}
@Override
protected Boolean doInBackground(final String... args) {
try {
Utilities.arrayRSS = objRSSFeed
.FetchRSSFeeds(Constants.Feed_URL);
return true;
} catch (Exception e) {
Log.e("tag", "error", e);
return false;
}
}
@Override
protected void onPostExecute(final Boolean success) {
if (dialog.isShowing()) {
dialog.dismiss();
}
// Setting data to list adapter
setListData();
}
回答by Haresh Chaudhary
Do This:-
做这个：-
Declarethe ProgressDialog at the Top.
ProgressDialog pd;Startit in onPreExecuteMethod of Async Task.
pd=ProgressDialog.show(ActivityName.this,"","Please Wait",false);Stopit in the onPostExecuteMethod.
pd.dismiss();
在顶部声明ProgressDialog。
ProgressDialog pd;在异步任务的onPreExecute方法中启动它。
pd=ProgressDialog.show(ActivityName.this,"","Please Wait",false);在onPostExecute方法中停止它。
pd.dismiss();
回答by koti
In onCreate method call some like below
在 onCreate 方法中调用如下
mdialog=new Dialog(this);
new LongOperation().execute("");
Then override onPostExecute of AyncTask
然后覆盖 AyncTask 的 onPostExecute
@Override
protected void onPostExecute() {
runOnUiThread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
mdialog.dismiss();
}
});
}
