[英]Call Async task from start of activity in android
我的应用程式中有一个类似Async的工作:
private class getUserSummary extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(DashboardActivity.this);
pDialog.setMessage("Getting sales summary...");
//pDialog.setTitle("Getting sales summary...");
pDialog.setIndeterminate(true);
pDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected JSONObject doInBackground(String... strings) {
String JsonResponse = null;
String JsonDATA = "email=my email address";
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
try {
ServiceUrl smf = new ServiceUrl();
URL url = new URL(smf.getUserSummaryUrl());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setDoOutput(true);
// is output buffer writter
urlConnection.setRequestMethod("GET");
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
//set headers and method
Writer writer = new BufferedWriter(new OutputStreamWriter(urlConnection.getOutputStream(), "UTF-8"));
writer.write(JsonDATA);
// json data
writer.close();
int responseCode = urlConnection.getResponseCode();
if (responseCode == 400) {
InputStream inputResponse = urlConnection.getErrorStream();
reader = new BufferedReader(new InputStreamReader(inputResponse));
StringBuffer errorBuffer = new StringBuffer();
String errorLine;
while ((errorLine = reader.readLine()) != null) {
errorBuffer.append(errorLine + "\n");
}
Log.i("Error text", errorBuffer.toString());
return new JSONObject(errorBuffer.toString());
}
//Log.i("Response code", String.valueOf(inputStream));
InputStream inputStream = urlConnection.getInputStream();
//input stream
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String inputLine;
while ((inputLine = reader.readLine()) != null)
buffer.append(inputLine + "\n");
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
JsonResponse = buffer.toString();
//response data
Log.i("RESPONSE", JsonResponse);
return new JSONObject(JsonResponse);
} catch (ProtocolException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("ERROR", "Error closing stream", e);
}
}
}
return null;
}
protected void onPostExecute(JSONObject result) {
pDialog.dismiss();
//post operation here
}
}
并在onCreate()方法中调用它
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dashboard);
ButterKnife.bind(this);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
initCollapsingToolbar();
new getUserSummary().execute();
}
用户登录活动遭到破坏后,我将立即运行它。 这就是为什么我需要在onCreate()方法上调用它。 但是在onCreate()方法中调用此方法时出现此错误
android.view.WindowLeaked: Activity softlogic.computers.softlogicsalesreward.DashboardActivity has leaked window com.android.internal.policy.PhoneWindow$DecorView{5329b90 V.E...... R......D 0,0-1002,348} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:603)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:326)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:109)
at android.app.Dialog.show(Dialog.java:505)
at softlogic.computers.softlogicsalesreward.DashboardActivity$getUserSummary.onPreExecute(DashboardActivity.java:88)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:604)
at android.os.AsyncTask.execute(AsyncTask.java:551)
at softlogic.computers.softlogicsalesreward.DashboardActivity.onResume(DashboardActivity.java:65)
at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1287)
at android.app.Activity.performResume(Activity.java:7015)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4210)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4323)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3426)
at android.app.ActivityThread.access$1100(ActivityThread.java:229)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7325)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
还有其他活动可以打电话吗? 还是我做错了什么?
您忘记调用pDialog.dismiss();。 在异步任务的onPostExecute方法中
您的asyncTask必须是这样的。看完您的代码后,您可能会忘记一些AsyncTask的方法了,请与本示例进行比较以更好地理解。
这是asyncTask的完整示例:
private class AsyncTaskRunner extends AsyncTask<String, String, String> {
private String resp;
ProgressDialog progressDialog;
@Override
protected String doInBackground(String... params) {
publishProgress("Sleeping..."); // Calls onProgressUpdate()
try {
int time = Integer.parseInt(params[0])*1000;
Thread.sleep(time);
resp = "Slept for " + params[0] + " seconds";
} catch (InterruptedException e) {
e.printStackTrace();
resp = e.getMessage();
} catch (Exception e) {
e.printStackTrace();
resp = e.getMessage();
}
return resp;
}
@Override
protected void onPostExecute(String result) {
// execution of result of Long time consuming operation
progressDialog.dismiss();
finalResult.setText(result);
}
@Override
protected void onPreExecute() {
progressDialog = ProgressDialog.show(MainActivity.this,
"ProgressDialog",
"Wait for "+time.getText().toString()+ " seconds");
}
@Override
protected void onProgressUpdate(String... text) {
finalResult.setText(text[0]);
}
}
像这样打电话:
new AsyncTaskRunner (this).execute();
您可以为此使用线程策略。 很好 只需在setcontent下添加两行。
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.build();
StrictMode.setThreadPolicy(policy);
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