I have written some code to do a httpGet and then return the JSON back to the main thread. Sometimes though the server is down and I want to report back to the main thread that the server is down but don't know how to do it properly using the handler.
My code looks like this:
public class httpGet implements Runnable {
private final Handler replyTo;
private final String url;
public httpGet(Handler replyTo, String url, String path, String params) {
this.replyTo = replyTo;
this.url = url;
}
#Override
public void run() {
try {
// do http stuff //
} catch (ClientProtocolException e) {
Log.e("Uh oh", e);
//how can I report back with the handler about the
//error so I can update the UI
}
}
}
Send a message to the handler, with some error code, for example:
Message msg = new Message();
Bundle data = new Bundle();
data.putString("Error", e.toString());
msg.setData(data);
replyTo.sendMessage(msg);
In the handler's handleMessage implementation handle this message.
The handler should look like this:
Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
Bundle data = msg.getData();
if (data != null) {
String error = data.getString("Error");
if (error != null) {
// do what you want with it
}
}
}
};
#Override
public void run() {
try {
// do http stuff //
} catch (ClientProtocolException e) {
Log.e("Uh oh", e);
//how can I report back with the handler about the
//error so I can update the UI
// you can use handleMessage(Message msg)
handler.sendEmptyMessage(-1) <-- sample parameter
}
}
Get the Message from Runnable here,
Handler handler = new Handler() {
public void handleMessage(Message msg) {
if(msg.what == -1) {
// report here
}
}
};
Besides handler you can use runOnUiThread,
#Override
public void run() {
try {
// do http stuff //
} catch (ClientProtocolException e) {
Log.e("Uh oh", e);
//how can I report back with the handler about the
//error so I can update the UI
runOnUiThread(new Runnable() {
#Override
public void run() {
// report here
}
}
}
}
Related
I would like to use the information of 'result' in the XMLRPCMethod. When the thread is finished the correct data is in the result object.
This is a code snipped from my OpenerpRPC.java class.
class XMLRPCMethod extends Thread {
private String method;
private Object[] params;
private Handler handler;
public Object result;
private OpenerpRpc callBack;
public XMLRPCMethod(String method, OpenerpRpc callBack) {
this.method = method;
this.callBack = callBack;
handler = new Handler();
}
public void call() {
call(null);
}
public void call(Object[] params) {;
this.params = params;
start();
}
#Override
public void run() {
try {
result = client.callEx(method, params);
handler.post(new Runnable() {
public void run() {
try {
callBack.resultcall(result);
} catch (XMLRPCException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
} catch (final XMLRPCFault e) {
handler.post(new Runnable() {
public void run() {
Log.d("Test", "error", e);
}
});
} catch (final XMLRPCException e) {
handler.post(new Runnable() {
public void run() {
Throwable couse = e.getCause();
if (couse instanceof HttpHostConnectException) {
Log.d(TAG, "error"+uri.getHost());
} else {
Log.d("Test", "error", e);
}
Log.d("Test", "error", e);
}
});
}
}
}
My result call in the OpenerpRpc class looks like:
public void resultcall(Object result) throws XMLRPCException{
allres=result;
if (rtype.equals("login")){
//Isn't impossible cast the result var with (String) because cause crash..why?
userid=""+result;
}
if (rtype.equals("read")){
//Isn't impossible cast the result var with (String) because cause crash..why?
// userid=""+result;
}
// name of callback function to use in parent class (MainActivity) for receive data
this.parent.oerpcRec(rtype,allres);
}
This is how i can receive the data in mainactivity
#SuppressWarnings("unchecked")
public void oerpcRec(String rtype,Object res) throws XMLRPCException{
if (rtype=="login"){
connector.setModel("res.users");
Object[] Ids = {Integer.parseInt(connector.userid)};
// set here the fields you wont loads
Object[] values={"name"};
connector.Read(Ids,values);
}
if(rtype=="read"){
Object[] ret=(Object[])res;
Map<String, Object> map1 = (Map<String, Object>) ret[0];
if(ret.length > 1){
}
}
}
But how can i get this information in my mainactivity? I only get the information of the login id value. When I put a breakpoint in the thread it only goes to the function resultcall when I try to login.
...
public void onClick(View v) {
try {
//here set user and pass for login
connector.Login(USER,PASS);
Object[] ids = {31,30,28,26};
Object[] params ={"partner_id","tax_line","section_id","invoice_line"};
connector.Read(ids,params);
//get information of openERP for specific id's
} catch (XMLRPCException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Use an interface
public interface MyListener {
public void callback(Object result);
}
Your MainActivity must implement the interface
public class MyActivity extends Activity implements MyListener {
...
...
...
#override
public void callback(Object result) {
// getting the result value.
}
}
So when your thread finish, execute the callback() method:
MyListener ml;
ml.callback(result);
and the callback() method of you MainActivity will receive the object.
I have created a service and for inter-service communication I am using a Messenger with a Handler.
public class LocalHandler extends Handler
{
public void handleMessage(Message message)
{
String msg = message.getData().getString("MyString");
String serv_msg = message.getData().getString("FromService");
Toast.makeText(getApplicationContext(), msg+serv_msg,
Toast.LENGTH_SHORT).show();
}
}
final Messenger myMessenger = new Messenger(new LocalHandler());
Now I want to check at any particular time how many messages are there in the MessageQueue of the messenger.
I searched the web but couldnt find anything on the topic.
Any leads about how I can get the list/count of messages?
There is a blog post from Square on how to spy for Looper's queue: https://corner.squareup.com/2013/12/android-main-thread-2.html
Here is how they do it for main Looper:
public class MainLooperSpy {
private final Field messagesField;
private final Field nextField;
private final MessageQueue mainMessageQueue;
public MainLooperSpy() {
try {
Field queueField = Looper.class.getDeclaredField("mQueue");
queueField.setAccessible(true);
messagesField = MessageQueue.class.getDeclaredField("mMessages");
messagesField.setAccessible(true);
nextField = Message.class.getDeclaredField("next");
nextField.setAccessible(true);
Looper mainLooper = Looper.getMainLooper();
mainMessageQueue = (MessageQueue) queueField.get(mainLooper);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public void dumpQueue() {
try {
Message nextMessage = (Message) messagesField.get(mainMessageQueue);
Log.d("MainLooperSpy", "Begin dumping queue");
dumpMessages(nextMessage);
Log.d("MainLooperSpy", "End dumping queue");
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
public void dumpMessages(Message message) throws IllegalAccessException {
if (message != null) {
Log.d("MainLooperSpy", message.toString());
Message next = (Message) nextField.get(message);
dumpMessages(next);
}
}
}
I am having problems with updating the TextView, I used the Handler method to pass the message to the UI. My application receives data(type integers) true io stream and shows in TextView.
My Activity class looks like this:
public class DeviceView extends Activity {
TextView dataX;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.device_view);
dataX = (TextView) findViewById(R.id.datax);
handler = new Handler() {
#Override
public void handleMessage(Message msg) {
dataX.setText(String.valueOf(msg.arg1));
}
};
}
}
I also have a separate class it extends Thread:
public class IOThread extends Thread {
public void run() {
byte[] buffer = new byte[1024];
int data;
while (true) {
try {
data = in.read(buffer);
Message message= Message.obtain();
message.arg1= data;
DeviceView.handler.sendMessage(message);
} catch (IOException ex) {
break;
}
}
}
}
Do I have to make a separate variable type String and point it to variable data and at last calling the count? Would that be enough to update TextView?
Can you try using an interface. Let the Activity implement it, pass it to the IOThread class. Once you get the result, pass the result to the Activity.
Interface named InterfaceData
public void getData(int data);
public class DeviceView extends Activity implements InterfaceData{
TextView dataX;
Handler handler;
IOThread ioThread;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.device_view);
handler = new Handler();
ioThread = new IOThread(this);
dataX = (TextView) findViewById(R.id.datax);
}
#Override
public void getData(int data){
handler.postDelayed(new Runnable(){
public void run(){
dataX.setText(data);
};
},100);
}
}
> Thread class
public class IOThread extends Thread {
InterfaceData interfaceData;
public IOThread(InterfaceData interfaceData){
this.interfaceData = interfaceData;
}
public void run() {
byte[] buffer = new byte[1024];
int data;
while (true) {
try {
data = in.read(buffer);
interfaceData.getData(data);
} catch (IOException ex) {
break;
}
}
}
}
I have found my problem it was not the Handler issue. THe code i posted at the beginning is coorect. The problem lyis on the way i read the received bytes[] array from the InputStream. I have tested by sending an integer int numbers = (int) 2 and when print this receivd data in terminal in Android app, it receivs only 1, even if i send int 3 or 4, i stil receive 1.
So i preceiated your example code #dcanh121 , but my question is actualy how do i read properly the integers that the server sends?
public void run() {
byte[] buffer = new byte[1024];
int data;
while (true) {
try {
data = in.read(buffer);
Log.d(TAG + data, "test");
Message message = Message.obtain();
message.arg1 = data;
Log.d(TAG + message.arg1, "test");
DeviceView.handler.sendMessageDelayed(message, 100);
} catch (IOException ex) {
Log.e(TAG_IOThread, "disconnected", ex);
break;
}
}
}
Here is the problem:
private void doSomething() {
String[][] data = new String[h][w];
Message msg = null;
Thread t = new Thread() {
public void run() {
for(int i=0; i<max; i++) {
data = doLongCalculationOnBackground(i);
msg = messageHandler.obtainMessage();
msg.obj = data;
messageHandler.sendMessage(msg);
}
}
};
t.start();
}
private Handler messageHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
doUpdateUI(msg.obj); // error right here!!!
}
};
private doUpdateUI(String[][] data) {
// do update UI work.
}
Eclipse alerts that doUpdateUI(msg.obj) is not applicable for the arguments (Object).
So how can i obtain the string matrix sent by Message object? Please don't suggest me use Async Task.
I'm stupid, just cast argument msg.obj to String[][]:
doUpdateUI((String[][]) msg.obj);
I've seen a bunch of posts related to this, but none seem to have the same issue I'm getting. GetBusinessRulesTask extends AsyncTask. When I execute this in a unit test case the onPostExecute() never gets called. However, if I use the real client code then onPostExecute() is called everytime. Not sure what I'm doing wrong here.
Test Case:
package com.x.android.test.api;
import java.util.concurrent.CountDownLatch;
import android.test.ActivityInstrumentationTestCase2;
import android.test.UiThreadTest;
import android.widget.Button;
import com.x.android.api.domain.businessrule.BusinessRules;
import com.x.android.api.exception.NetworkConnectionException;
import com.x.android.api.tasks.GetBusinessRulesTask;
import com.x.android.test.activity.SimpleActivity;
public class GetBusinessRulesTaskTest
extends
ActivityInstrumentationTestCase2<SimpleActivity> {
SimpleActivity mActivity;
Button mButton;
public GetBusinessRulesTaskTest() {
super("com.x.android.test.activity", SimpleActivity.class);
}
#Override
protected void setUp() throws Exception {
super.setUp();
mActivity = this.getActivity();
mButton = (Button) mActivity
.findViewById(com.x.android.test.activity.R.id.b1);
}
public void testPreconditions() {
assertNotNull(mButton);
}
#UiThreadTest
public void testCallBack() throws Throwable {
final CountDownLatch signal = new CountDownLatch(1);
final GetBusinessRulesTask task = (GetBusinessRulesTask) new GetBusinessRulesTask(
new GetBusinessRulesTask.Receiver<BusinessRules>() {
#Override
public void onReceiveResult(BusinessRules rules, Exception e) {
assertNotNull(rules);
assertNull(e);
signal.countDown();// notify the count down latch
}
});
task.start(mActivity.getApplicationContext());
try {
signal.await();// wait for callback
} catch (InterruptedException e1) {
fail();
e1.printStackTrace();
}
}
}
OnPostExecute:
#Override
protected void onPostExecute(AsyncTaskResponse<O> response) {
Log.d(TAG, "onPostExecuted");
if (mReceiver != null) {
mReceiver.onReceiveResult(response.getResponse(), response.getException());
}
}
DoInBackground:
#Override
protected AsyncTaskResponse<O> doInBackground(I... params) {
Log.d(TAG, "doInBackgroundr");
try {
Uri uri = createUri(params);
mBaseRequest = new GetLegacyRequest(uri);
String json = mBaseRequest.executeRequest();
O response = deserializeJson(json);
Log.d(TAG, "Returning AsyncTaskResponse");
return new AsyncTaskResponse<O>(response, null);
} catch (Exception e) {
Log.e(TAG, "Error", e);
/*
AsyncTaskResponse<O> maintenance = ReadBusinessControlledPropertiesTask.blockingCall(mServiceLocatorUrl);
if(maintenance.getException() == null) {
MaintenanceException mExcep = new MaintenanceException( maintenance.getResponse());
if (mExcep.isUnderMaintenance())
return new AsyncTaskResponse(null,mExcep);
}*/
return new AsyncTaskResponse<O>(null, e);
}
}
Start method()
public AsyncTask<Void, Void, AsyncTaskResponse<BusinessRules>> start(
Context context) throws NetworkConnectionException {
super.start(context);
Log.d(TAG, "start");
return execute();
}
FOUND THE ISSUE. Don't make your AsyncTask final and put it inside the runnable.
The fix:
public void testCallBack() throws Throwable {
final CountDownLatch signal = new CountDownLatch(1);
// Execute the async task on the UI thread! THIS IS KEY!
runTestOnUiThread(new Runnable() {
#Override
public void run() {
try {
GetBusinessRulesTask task = (GetBusinessRulesTask)new GetBusinessRulesTask(new GetBusinessRulesTask.Receiver<BusinessRules>() {
#Override
public void onReceiveResult(
BusinessRules rules, Exception e) {
assertNotNull(rules);
assertNull(e);
signal.countDown();// notify the count downlatch
}
});
task.start(mActivity.getApplicationContext());
} catch (Exception e) {
Log.e(TAG, "ERROR", e);
fail();
}
}
});
try {
signal.await();// wait for callback
} catch (InterruptedException e1) {
fail();
e1.printStackTrace();
}
}
FOUND THE ISSUE. Don't make your AsyncTask final and put it inside the runnable.
The fix:
public void testCallBack() throws Throwable {
final CountDownLatch signal = new CountDownLatch(1);
// Execute the async task on the UI thread! THIS IS KEY!
runTestOnUiThread(new Runnable() {
#Override
public void run() {
try {
GetBusinessRulesTask task = (GetBusinessRulesTask)new GetBusinessRulesTask(new GetBusinessRulesTask.Receiver<BusinessRules>() {
#Override
public void onReceiveResult(
BusinessRules rules, Exception e) {
assertNotNull(rules);
assertNull(e);
signal.countDown();// notify the count downlatch
}
});
task.start(mActivity.getApplicationContext());
} catch (Exception e) {
Log.e(TAG, "ERROR", e);
fail();
}
}
});
try {
signal.await();// wait for callback
} catch (InterruptedException e1) {
fail();
e1.printStackTrace();
}
}