Develop Reference

Send http-get from PreferenceFragment (live-wallpaper)

I created a wallpaper (for my Android 4.0.3) but I have a problem with the preferences.
When I try to invoke a service http-get from PreferenceFragment, I do not get any response. In practice, it seems that call is lost. I tried with a call like:
InputStream stream = null;
StringBuilder fos = null;
try {
URL url = new URL("http://.....");
stream = url.openConnection().getInputStream();
InputStreamReader reader = new InputStreamReader(stream);
fos = new StringBuilder();
int next = -1;
while ((next = reader.read()) != -1) {
fos.append((char)next);
}
} catch (Exception e) {
// ...
} finally {
// ...
}
or with an external framework like libgdx:
HttpRequest httpRequest = new HttpRequest(HttpMethods.GET);
httpRequest.setUrl("http://.....");
NetJavaImpl net = new NetJavaImpl();
net.sendHttpRequest(httpRequest, this);
but nothing happened. On the device no trace about this or a probability exception is present.
I have a manifest like this:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="it.mytest.live"
android:installLocation="preferExternal"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.SET_WALLPAPER" />
<uses-feature
android:name="android.software.live_wallpaper"
android:required="true" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".MyWallpaperSettings"
android:exported="true"
android:hardwareAccelerated="false"
android:label="MyWallpaperSettings"
android:permission="android.permission.INTERNET" />
<service
android:name=".MyWallpaper"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:permission="android.permission.BIND_WALLPAPER" >
<intent-filter>
<action android:name="android.service.wallpaper.WallpaperService" />
</intent-filter>
<meta-data
android:name="android.service.wallpaper"
android:resource="#xml/livewallpaper"
android:value="true" />
</service>
</application>
</manifest>
Do you have any idea? I'm going crazy :(
*edit: Solved, Thanks!! *
private class SendAsyncTask extends AsyncTask<String, String, String>
{
protected String doInBackground(String... status)
{
String result = "";
try
{
String url = "my magic http-get";
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(new HttpGet(url));
if(response != null && response.getEntity() != null)
{
InputStream stream = response.getEntity().getContent();
try
{
// parse an XML with libgdx ...
XmlReader xmlReader = new XmlReader();
Element root = xmlReader.parse(stream);
Array<Element> childs = root.getChildrenByNameRecursively("mykids");
for (Element child: childs)
{
Element myelement = child.getChildByName("name");
//do something...
}
}
catch (Exception e)
{
//
}
finally
{
try
{
stream.close();
}
catch (Exception e)
{
//
}
}
}
}
catch (Exception e)
{
//
}
return result;
}
protected void onPostExecute(String result)
{
super.onPostExecute(result);
}
}

You could possibly get a NetworkOnMainThreadException because you made a network connection in a PreferenceFragment, which runs on main UI thread.
If so, you could move network jobs to a background service. Note that Service runs on main UI thread too. So you need Thread inside the service.
A side note: it seems you swallowed all exceptions with:
try {
// ...
} catch (Exception e) {
// ... => HERE
}

UDP Packets (via WiFi Direct) never arrive

those of you who read my previous questions may already know this: I'm currently trying to get a hold on the whole WiFi Direct stuff. What I've done so far is creating the connection.
What I'm trying to do is sending a packet via UDP to the groupOwner (which's IP is of course known) - but it seems to get lost on it's way each time..
Here's a bit of my code, I've got a service for receiving files and an intentservice for submitting them in the background:
FileReceiverService.java
#Override
public void run() {
Log.d(TAG, "Thread starting...");
try {
app.log("Opening UDP socket to receive files.");
DatagramSocket socket = new DatagramSocket(PORT);
app.log("Socket open!");
socket.setSoTimeout(5000);
app.log("Waiting for packet..");
while (isRunning && !isInterrupted()) {
DatagramPacket packet = new DatagramPacket(
new byte[WiFiPacket.PACKET_SIZE],
WiFiPacket.PACKET_SIZE);
try {
socket.receive(packet);
app.log("Received " + packet.getLength()
+ " bytes, trying to parse!");
parsePacket(packet);
} catch (SocketTimeoutException e) {
} catch (Exception e) {
app.log("Something went wrong: " + e.getMessage());
e.printStackTrace();
}
}
socket.close();
app.log("Closing UDP socket");
} catch (Exception e) {
e.printStackTrace();
}
}
Where the constant WiFiPacket.PACKET_SIZE is set to 1024*32 (32 KBytes, because I've received "ERRBLABLA MSG too long" errors with higher values).
FileTransferService.java
#Override
protected void onHandleIntent(Intent intent) {
App app = (App) getApplication();
Context context = getApplicationContext();
boolean rightIntent = false;
WiFiFile file = null;
if (intent.getAction().equals(ACTION_SEND_TEXT)) {
rightIntent = true;
file = WiFiFile.fromText(intent.getExtras().getString(EXTRAS_TEXT));
} else if (intent.getAction().equals(ACTION_SEND_FILE)) {
rightIntent = true;
file = WiFiFile.fromFile(intent.getExtras().getString(
EXTRAS_FILE_PATH));
}
if (rightIntent && file != null) {
app.getOnWiFiTransmissionChangedListener().onNewOutgoingTransfer(
file);
String text = intent.getExtras().getString(EXTRAS_TEXT);
String host = intent.getExtras().getString(
EXTRAS_GROUP_OWNER_ADDRESS);
DatagramSocket socket = null;
int port = intent.getExtras().getInt(EXTRAS_GROUP_OWNER_PORT);
Log.d(TAG, "Sending packets to " + host + ":" + port);
try {
socket = new DatagramSocket();
int bytesSent = 0;
for (WiFiPacket p : file) {
Log.d(TAG, "Preparing another packet..");
byte[] payload = p.getBytes();
DatagramPacket packet = new DatagramPacket(payload,
payload.length, InetAddress.getByName(host), port);
Log.d(TAG, "Sending packet..");
socket.send(packet);
bytesSent += payload.length;
Log.d(TAG, "Packet send! Contained " + payload.length
+ " bytes! All over we've sent about " + bytesSent
+ " bytes!");
List<WiFiFile> list = new ArrayList<WiFiFile>();
list.add(file);
app.getOnWiFiTransmissionChangedListener()
.onTransferProgressChanged(list);
}
app.getOnWiFiTransmissionChangedListener()
.onFileTransferSuccessful(file);
Log.d(TAG, "Client: Data written");
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, e.getMessage());
} finally {
if (socket != null) {
if (socket.isConnected()) {
socket.close();
}
}
}
}
}
The code may not be the best, but as for right now the only thing I care about is to receive the damn packet. :)
For your information: I'm splitting instances of the class WiFiFile into WiFiPackets which do not exceed the PACKET_SIZE limit, thus contain some sort of own header information about the file's offset, the total length, the sender (username/inetaddress) and stuff like that.
My logging tells me that about 25KBytes were sent, the socket.send does not throw any errors but instead calls my listeners (also the one telling me the transfer is completed).
As far as I know, UDP packets can easily be dropped on their way, but I've tried it roughly 10 times and I think the probability of a 25KB packet getting lost EVERYTIME is very small.
Do you see anything I'm missing? I'm staring at my code since hours, trying to figure it out, putting more and more debug/log statements in it, but without any progress.
Thanks!
PS:
IP addresses and port are correct.
PS2:
AndroidManifest.xml
<uses-feature
android:name="android.hardware.wifi.direct"
android:required="true" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.CHANGE_COMPONENT_ENABLED_STATE" />

Okay, I solved this problem.
I sent the messages directly after receiving the callback for a successful group creation, thinking that the group really would be "ready"... Solved this by sending out an initial message in a TimerTask every ~200-500ms, cancelling the Task after receiving ack.
Hope this helps some of you, facing the same problem. :)

Source not found error

i am new android developer
when ever i run this code i get this error "Source not found." just when it reaches the
url.openStream()
any idea how to fix this?
try {
URL url = new URL("http://pollsdb.com/test.txt");
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String str;
while ((str = in.readLine()) != null) {
}
in.close();
} catch (MalformedURLException e) {
} catch (IOException e) {
}

<uses-permission
android:name="android.permission.INTERNET" />
add that under your first manifest tag in your AndroidManifest.xml

I have the same problem too. But now, i have been solved this problem by reference http://developer.android.com/guide/components/processes-and-threads.html
about the thread use.
You need to create a worker thread to work for open the URL stream rather than using the main thread(UI thread).
Of course, you also need to add
<uses-permission android:name="android.permission.INTERNET" />
in your AndroidManifest.xml

Android network errors connecting to an address

Snippet provided:
public void update(){
try {
Socket appSoc = new Socket( "XXX.XXX.XXX.X" ,XXXXX);
BufferedReader in = new BufferedReader(new
InputStreamReader(appSoc.getInputStream()));
for (int i = 0; i < 100; i++) {
String message = in.readLine();
add(message);}
}
catch (Exception e) {
add("ERROR" + e);
}
}
add(String text) adds text to a textview.
Using the domain name instead of the IP address says that the phone cannot find the domain, is this an android problem, because it runs fine on java on the desktop.

You are probably missing the Internet persmission in your manifest. Make sure it is located outside of the application tag, like this:
<manifest>
<application>
.
.
.
</application>
<uses-permission android:name="android.permission.INTERNET" />
</manifest>

In your androidmanifest.xml, check to see if you have given proper internet permissions.
<uses-permission android:name="android.permission.INTERNET"></uses-permission>

Unknown host Exception while calling method " twitter.getOAuthRequestToken()"

I am trying to integrate twitter api using library twitter4j-core-2.1.1-SNAPSHOT.jar. But i am getting error Unknown host Exception from 2 days. here is the part of code(index by .....(1)) that is generating Exception.
public String beginAuthorization() {
//showDialog("Authorization...........");
//new AuthorizationTask(this).execute("Authorize");
try {
if (null == currentRequestToken) {
Log.e("begin","i am here the line below is throwing excetion");
currentRequestToken = twitter.getOAuthRequestToken();............(1)
}
Log.e("beginAuthorization", currentRequestToken.getAuthorizationURL());
return currentRequestToken.getAuthorizationURL();
} catch (TwitterException e) {
e.printStackTrace();
}
return null;
}
anyone have idea about this problem???
thank u in advance

Did you put permission in xml manifest?
Have you tried opening a browser in android and going to twitter.com?
Try to connect to any url from the code and see what happens.

This is what I'd forgotten to include in my AndroidManifest.xml:
<uses-permission android:name="android.permission.INTERNET" />