La aplicación de Android se bloquea/bloquea al enviar datos en un nuevo hilo al hacer clic en el botón
So, on a button click, I create a new thread and then I am sending data to an asp.net script and after sending the data, I am "clearing" the EditText field. But, after I send the data, the textview is not cleared and the app freezes and sometimes crashes. Here is my Activity code:
http://www.mstreetllc.com/Lab.asp
package com.example.testphp;
import java.io.IOException;
import org.apache.http.client.ClientProtocolException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.message.BasicNameValuePair;
// import everything you need
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
Button sendButton;
EditText msgTextField;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// load the layout
setContentView(R.layout.fragment_main);
// make message text field object
msgTextField = (EditText) findViewById(R.id.msgTextField);
// make send button object
sendButton = (Button) findViewById(R.id.sendButton);
sendButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Thread thread = new Thread(new Runnable(){
@Override
public void run() {
try {
// get the message from the message text box
String msg = msgTextField.getText().toString();
// make sure the fields are not empty
if (msg.length() > 0) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.mstreetllc.com/Lab.asp");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("message", msg));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
msgTextField.setText(""); // clear text box
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
} else {
// display message if text fields are empty
Toast.makeText(getBaseContext(), "All field are required",
Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
thread.start();
}
});
}
}
I'm not sure if it is the thread or the sending of the data that is making it freeze. Any ideas?
gato de registro:
05-28 09:45:32.325: W/System.err(32478): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
05-28 09:45:32.341: W/System.err(32478): at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:5908)
05-28 09:45:32.341: W/System.err(32478): at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:869)
05-28 09:45:32.341: W/System.err(32478): at android.view.ViewGroup.invalidateChild(ViewGroup.java:4253)
05-28 09:45:32.341: W/System.err(32478): at android.view.View.invalidate(View.java:10489)
05-28 09:45:32.341: W/System.err(32478): at android.widget.TextView.invalidateRegion(TextView.java:4591)
05-28 09:45:32.341: W/System.err(32478): at android.widget.TextView.invalidateCursor(TextView.java:4534)
05-28 09:45:32.341: W/System.err(32478): at android.widget.TextView.spanChange(TextView.java:7412)
05-28 09:45:32.341: W/System.err(32478): at android.widget.TextView$ChangeWatcher.onSpanAdded(TextView.java:9103)
05-28 09:45:32.341: W/System.err(32478): at android.text.SpannableStringBuilder.sendSpanAdded(SpannableStringBuilder.java:979)
05-28 09:45:32.341: W/System.err(32478): at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:688)
05-28 09:45:32.341: W/System.err(32478): at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:588)
05-28 09:45:32.349: W/System.err(32478): at android.text.Selection.setSelection(Selection.java:76)
05-28 09:45:32.349: W/System.err(32478): at android.text.Selection.setSelection(Selection.java:87)
05-28 09:45:32.349: W/System.err(32478): at android.text.method.ArrowKeyMovementMethod.initialize(ArrowKeyMovementMethod.java:302)
05-28 09:45:32.349: W/System.err(32478): at android.widget.TextView.setText(TextView.java:3759)
05-28 09:45:32.349: W/System.err(32478): at android.widget.TextView.setText(TextView.java:3629)
05-28 09:45:32.349: W/System.err(32478): at android.widget.EditText.setText(EditText.java:80)
05-28 09:45:32.349: W/System.err(32478): at android.widget.TextView.setText(TextView.java:3604)
05-28 09:45:32.349: W/System.err(32478): at com.example.testphp.MainActivity$1$1.run(MainActivity.java:68)
05-28 09:45:32.349: W/System.err(32478): at java.lang.Thread.run(Thread.java:841)
preguntado el 28 de mayo de 14 a las 14:05
nick
5 Respuestas
Only the UI thread can make changes to the UI. Any changes to views in your thread need to be done in runOnUIThread blocks or sent to the UI thread via a handler.
contestado el 28 de mayo de 14 a las 14:05
El problema con su código es el
msgTextField.setText("");
As cited in the error message, you cannot access your view hierarchy from an alternative thread. Only the main UI thread can access it.
Es posible que desee mirar en Tarea asíncrona class which is exactly what you need for distant server access. You would then execute the code on the doInBackground() method and then modify the view onPostExecute().
contestado el 28 de mayo de 14 a las 14:05
The Problem is, that you are trying to update the UI-Thread from a Non-UI-Thread.
You could try as following (not tested):
public void onClick(View v) {
new Thread(new Runnable() {
public void run() {
msgTextField.post(new Runnable() { //<-- This instead of your setText();
public void run() {
mImageView.setText("");
}
});
}
}).start();
}
Referencias:
contestado el 23 de mayo de 17 a las 11:05
Deberías crear un AsyncTask y manejar el HttpPost allí.
public class Post extends AsyncTask<String, Void, Void> {
private Activity callingActivity = null;
public Post(Activity paramActivity) {
callingActivity = paramActivity;
}
protected Void doInBackground(String... msg) {
if (msg[0].length() > 0) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.mstreetllc.com/Lab.asp");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("message", msg[0]));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
}
catch (ClientProtocolException e) {
// TODO Auto-generated catch block
}
catch (IOException e) {
// TODO Auto-generated catch block
}
}
}
protected void onPostExecute(Void result) {
EditText msgTextField = (EditText) callingActivity.findViewById(R.id.msgTextField);
msgTextField.setText("");
}
}
To call this AsyncTask, simplemente escribe:
new Post(this).execute(msg);
Para más información sobre AsyncTasks: http://developer.android.com/reference/android/os/AsyncTask.html
contestado el 28 de mayo de 14 a las 15:05
No es la respuesta que estás buscando? Examinar otras preguntas etiquetadas java android asp.net multithreading or haz tu propia pregunta.
Have you got any logcat of the issue? - UeliDeSchwert