How do I switch activities when an asynchronous connection returns?… here is a solution to the problem.
How do I switch activities when an asynchronous connection returns?
Simple concept of invalidity:
I’m trying to connect to the web and retrieve some data using an asynchronous connection. When the connection returns data, I want to switch to another activity. My code is not working.
I’m assuming I need to use some kind of callback, but I’m new to Android/Java and can’t find an answer on how to do this by googling. Can someone take a look and suggest how I can create a callback that starts an intent when the data returns? :
*Update: I found this nice library herehttp://loopj.com/android-async-http/ This is another (simple) way to connect to the network in the background.
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mtmobtest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:icon="@drawable/icon"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=". MTMobTestActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="MainMenu"
android:name=". MainMenu" >
<intent-filter >
<action android:name="android.intent.action.MAINMENU" />
<category android:name="android.intent.category.MAINMENU" />
</intent-filter>
</activity>
</application>
</manifest>
MTMobTestActivity.java
package com.mtmobtest;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Window;
import android.widget.Toast;
import android.widget.ViewFlipper;
public class MTMobTestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
postData("Sup yall");
setContentView(R.layout.main);
}
public void postData(String toPost) {
Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.example.com/test.php");
This is the data to send
String myName = "anybody there?"; any data to send
try {
Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
nameValuePairs.add(new BasicNameValuePair("action", myName));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
Execute HTTP Post Request
ResponseHandler<String> responseHandler = new BasicResponseHandler();
String response = httpclient.execute(httppost, responseHandler);
This is the response from a php application
String reverseString = response;
ViewFlipper vf = (ViewFlipper) findViewById(R.layout.menu);
Set an animation from res/anim: I pick push left in
vf.setAnimation(AnimationUtils.loadAnimation(view.getContext(), R.anim.push_left_in));
vf.showNext();
Toast.makeText(this, "response" + reverseString, Toast.LENGTH_LONG).show();
} catch (ClientProtocolException e) {
Toast.makeText(this, "CPE response " + e.toString(), Toast.LENGTH_LONG).show();
TODO Auto-generated catch block
} catch (IOException e) {
Toast.makeText(this, "IOE response " + e.toString(), Toast.LENGTH_LONG).show();
TODO Auto-generated catch block
}
Intent intent = new Intent(this, MainMenu.class);
startActivity(intent);
}
}
Solution
Use AsyncTask and use AsyncTasks in onPostExecute A new activity is triggered in the method call.