can you explain to me what does this Code snippet do? I dont understand how the point object got parameters as byteBuffer, and whats the purpose of getInt(4) and getInt(8), why 4 and 8?
protected Point getEnd() {
ByteBuffer byteBuffer = null;
try {
final byte[] page = this.bufferManager.getPage(this.pageSize, new BufferManager.PageAddress(0, this.path1));
byteBuffer = ByteBuffer.wrap(page);
} catch (final IOException e) {
e.printStackTrace();
}
return new Point(byteBuffer.getInt(4), byteBuffer.getInt(8));
}
Related
I have been trying to display nearby locations from my current location. But when i run it and click the button to view the nearby locations nothing appears. The first time i ran it, it displayed but when i backed out and came back in, it didnt display anything. i tried cleaning the project and other methods.
this is the method in my main class:
public void findRestaurants(View v){
StringBuilder stringBuilder = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
stringBuilder.append("location="+latLngCurrent.latitude + "," +latLngCurrent.longitude);
stringBuilder.append("&radius="+5000);
stringBuilder.append("&keyword="+"restaurant");
stringBuilder.append("&key="+getResources().getString(R.string.google_map_keyy));
String url = stringBuilder.toString();
Object dataTransfer[] = new Object[2];
dataTransfer[0] = mMap;
dataTransfer[1] = url;
getNearbyPlaces getnearbyPlaces = new getNearbyPlaces();
getnearbyPlaces.execute(dataTransfer);
}
public class getNearbyPlaces extends AsyncTask<Object,String,String> {
GoogleMap mMap;
String url;
InputStream is;
BufferedReader bufferedReader;
StringBuilder stringBuilder;
String data;
#Override
protected String doInBackground(Object... objects) {
mMap = (GoogleMap)objects[0];
url = (String)objects[1];
try {
URL myurl = new URL(url);
HttpURLConnection httpURLConnection = (HttpURLConnection) myurl.openConnection();
httpURLConnection.connect();
is = httpURLConnection.getInputStream();
bufferedReader = new BufferedReader(new InputStreamReader(is));
String line = "";
stringBuilder = new StringBuilder();
while((line = bufferedReader.readLine() ) != null){
stringBuilder.append(line);
}
data = stringBuilder.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return data;
}
#Override
protected void onPostExecute(String s) {
try {
JSONObject parentObject = new JSONObject(s);
JSONArray resultsArray = parentObject.getJSONArray("results");
for (int i = 0; i<resultsArray.length(); i++){
JSONObject jsonObject = resultsArray.getJSONObject(i);
JSONObject locationObj = jsonObject.getJSONObject("geometry").getJSONObject("location");
String latitude = locationObj.getString("lat");
String longitude = locationObj.getString("lng");
JSONObject nameObject = resultsArray.getJSONObject(i);
String name_restaurant = nameObject.getString("name");
String vicinity = nameObject.getString("vicinity");
LatLng latLng = new LatLng(Double.parseDouble(latitude),Double.parseDouble(longitude));
MarkerOptions markeroptions = new MarkerOptions();
markeroptions.title(vicinity);
markeroptions.position(latLng);
mMap.addMarker(markeroptions);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
it worked the first time when i lunched it. Did i do something wrong?
hope you are doing fine. Can you replace the lines
new getNearbyPlaces().execute(dataTransfer);
instead of these 2 lines
getNearbyPlaces getnearbyPlaces = new getNearbyPlaces();
getnearbyPlaces.execute(dataTransfer);
I am not sure whether this is going to impact much, but this is the way AsyncTask class should be called.
If this is not working, can you share the entire code of this java page, so we can look at how findRestaurant() method is called.
It's probably pretty obvious, but I'm completely new to programming or asking a question at stackoverflow, so I apologize in advance if I can't explain myself properly. Also, there are some parts I have no idea what they are for anymore since the code is basically a mix of tutorials.
What I need the app to do is for it to keep doing what it's doing (the handler part), but while it's is closed (not minimized). But instead of changing the background, I need it to send a notification instead.
In other words, every 10 minutes, if the value of temperBU is 19, I get a notification even if the app is closed.
For that, if I'm not mistaken, what I need is a service, but I don't understand what type is better for this situation. I tried some tutorials, but nothing seems to work, and if it's possible to start the service as soon as the app gets started.
public class MainActivity extends AppCompatActivity {
ConstraintLayout layout;
class Weather extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... address) {
try {
URL url = new URL(address[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream is = connection.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
int data = isr.read();
String content = "";
char ch;
while (data != -1) {
ch = (char) data;
content = content + ch;
data = isr.read();
}
Log.i("Content", content);
return content;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String content;
Weather weather = new Weather();
{
{
try {
content = weather.execute("https://api.openweathermap.org/data/2.5/weather?q=budapest,hu&units=metric&appid=ce2fd10cdcc8ab209f979f6a41c27cfe").get();
JSONObject jsonObject = new JSONObject(content);
String mainData = jsonObject.getString("main");
Log.i("mainData", mainData);
JSONObject object = new JSONObject(mainData);
Double temp = object.getDouble("temp");
Log.i("temp", String.valueOf(temp));
int temperBU = (int) Math.round(temp);
Log.i("temperBU", String.valueOf(temperBU));
layout = findViewById(R.id.hs_n);
if (temperBU == 19)
layout.setBackgroundResource(R.drawable.hungry_summer_premium_yes_simple);
else layout.setBackgroundResource(R.drawable.hungry_summer_premium_no_simple);
Handler handler = new Handler();
Runnable r = new Runnable() {
public void run() {
String content;
Weather weather = new Weather();
try {
content = weather.execute("https://api.openweathermap.org/data/2.5/weather?q=budapest,hu&units=metric&appid=ce2fd10cdcc8ab209f979f6a41c27cfe").get();
JSONObject jsonObject = new JSONObject(content);
String mainData = jsonObject.getString("main");
Log.i("mainData", mainData);//*
JSONObject object = new JSONObject(mainData);
Double temp = object.getDouble("temp");
Log.i("temp", String.valueOf(temp));
int temperBU = (int) Math.round(temp);
Log.i("temperBU", String.valueOf(temperBU));//*
layout = findViewById(R.id.hs_n);
if (temperBU == 19)
layout.setBackgroundResource(R.drawable.hungry_summer_premium_yes_simple);
else
layout.setBackgroundResource(R.drawable.hungry_summer_premium_no_simple);
} catch (Exception e) {
e.printStackTrace();
}
handler.postDelayed(this::run, 600000);
}
};
handler.postDelayed(r, 600000);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
Thank you so much for the help.
Please note that AsyncTask is deprecated, so use the following to do a background work:
Android AsyncTask API deprecating in Android 11.What are the alternatives?
In order to continue doing something after the user closed your app try using foreground service, like this:
in Android manifest, add
uses-permission android:name="android.permission.FOREGROUND_SERVICE"
this inside the application tag:
service android:name=".services.WorkerSvc"
add this class:
class WorkerSvc : Service() {
override fun onBind(intent: Intent?): IBinder? {
return null
}
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
LogUtil.i("onStartCommand")
startForeground(
NotificationUtil.NOTIFICATION_ID,
NotificationUtil.makeForeGroundNotification(getString(R.string.please_wait))
)
processIntent(intent)
return START_STICKY
}
private fun processIntent(intent: Intent?) {
if (intent == null) {
stopSelf()
} else {
// DO YOUR WORK HERE. USE INTENT EXTRAS TO PASS DATA TO SERVICE
// NOTE THIS IS EXECUTED IN MAIN THREAD SO USE ONE OF THE SOLUTION PROVIDED IN A LINK ABOVE
}
}
}
To start the service:
val svcIntent = Intent(App.instance, WorkerSvc::class.java)
svcIntent.putExtra(
//DATA TO PASS TO SERVICE
)
if (context != null) {
ContextCompat.startForegroundService(context, svcIntent)
}
This is my method!
private String logInActivity() {
String userID = idText.getText().toString();
String userPW = pwText.getText().toString();
final String SERVER = "http://115.145.241.151:8080/AndroidCommunication/LoginActivity.jsp";
if (userID != null && userPW != null) {
final String QUERY = "?id=" + userID + "&pw=" + userPW;
HttpURLConnection connection = null;
URL url = null;
try {
url = new URL(SERVER+QUERY);
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
InputStream is = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line = reader.readLine();
return line;
} catch (Exception e) {
e.printStackTrace();
return "3";
}
} else {
Toast.makeText(GetReview.this, "Type all required info", Toast.LENGTH_SHORT).show();
return "2";
}
}
I'm just practicing HttpURLConnection( by GET METHOD). I know i shouldn't send passwords or ids like this way but i'm just practicing my exercise. But I just don't get why this goes to an Exception. Please help!
I didn't type my addresses or anything wrong because I tried it, and server was on. I debugged it and the connection.connect(); doesn't seems to work.
my onCreate goes:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_get_review);
pwText = findViewById(R.id.pwText);
idText = findViewById(R.id.idText);
resultText = findViewById(R.id.resultText);
findViewById(R.id.btnLogin).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new LoginAsyncTask().execute(logInActivity());
}
});
}
The problem is that issuing HTTP requests on the main thread is not allowed by android. That's why you are receiving a NetworkOnMainThreadException exception. To resolve this, you can use an IntentService to do that job for you and then broadcast the results back to the receiver (your activity).
If you don't know much about android Services, then have a read in the documentation, you'll find yourself using them time and time again...
https://developer.android.com/guide/components/services#CreatingAService
I've tried two different ways to call a simple REST method from Android; said REST method - which works from other clients - simply returns an int val such as 17.
Both of the following attempts were based on code I found online. One is like so:
public void onFetchBtnClicked(View v){
if(v.getId() == R.id.FetchBtn){
Toast.makeText(getApplicationContext(), "You mashed the button, dude.", Toast.LENGTH_SHORT).show();
new NetworkTask().execute();
}
}
public static class NetworkTask extends AsyncTask {
#Override
protected String doInBackground(Void... params) {
final String TAG;
TAG = "callWebService";
String deviceId = "Android Device";
HttpClient httpclient = new DefaultHttpClient();
HttpGet request = new HttpGet("http://localhost:28642/api/Departments/GetCount");
request.addHeader("deviceId", deviceId);
ResponseHandler<String> handler = new BasicResponseHandler();
String result = "";
try
{
result = httpclient.execute(request, handler);
}
catch (ClientProtocolException e)
{
e.printStackTrace();
Log.e(TAG, "ClientProtocolException in callWebService(). " + e.getMessage());
}
catch (IOException e)
{
e.printStackTrace();
Log.e(TAG, "IOException in callWebService(). " + e.getMessage());
}
httpclient.getConnectionManager().shutdown();
Log.i(TAG, "**callWebService() successful. Result: **");
Log.i(TAG, result);
Log.i(TAG, "*****************************************");
return result;
}
#Override
protected void onPostExecute(String result) {
final String TAG;
TAG = "onPostExecute";
if (null != result)
Log.i(TAG, result);
}
With the code above, after the following line of code fails:
result = httpclient.execute(request, handler) ;
...I get, "*E/callWebService﹕ IOException in callWebService(). Connection to http://localhost:28642 refused*"
This problem may be a threading issue, as I read this in O'Reilly's "Programming Android" book by Mednieks, Dornin, Meike, and Nakamura: "AsyncTask is a convenenient tool for running small, asynchronous tasks. Just remember that the doInBackground method runs on a different thread! It must not write any state visible from another thread or read any state writable from another thread. This includes its parameters."
With my other attempt:
public void onFetchBtnClicked(View v){
if(v.getId() == R.id.FetchBtn){
Toast.makeText(getApplicationContext(), "You mashed the button, dude.", Toast.LENGTH_SHORT).show();
callWebService("http://localhost:28642/api/Departments/GetCount");
}
}
public String callWebService(String requestUrl)
{
final String TAG;
TAG = "callWebService";
String deviceId = "Android Device";
HttpClient httpclient = new DefaultHttpClient();
HttpGet request = new HttpGet(requestUrl);
request.addHeader("deviceId", deviceId);
ResponseHandler<String> handler = new BasicResponseHandler();
String result = "";
try
{
result = httpclient.execute(request, handler);
}
catch (ClientProtocolException e)
{
e.printStackTrace();
Log.e(TAG, "ClientProtocolException in callWebService(). " + e.getMessage());
}
catch (IOException e)
{
e.printStackTrace();
Log.e(TAG, "IOException in callWebService(). " + e.getMessage());
}
httpclient.getConnectionManager().shutdown();
Log.i(TAG, "**callWebService() successful. Result: **");
Log.i(TAG, result);
Log.i(TAG, "*****************************************");
return result;
}
...the debugger dumps me into View.class after hitting that same problem line (result = httpclient.execute(request, handler)). Why it does that, I don't know*, but I think the crux of the problem, as indicated by err msgs in logcat, is: "Caused by: android.os.NetworkOnMainThreadException"
*Maybe because something untoward is being attempted within the UI (View) thread.
Also (not a big deal, but "interesting," perhaps): the Toast doesn't pop up when a method call is made after it (it works otherwise).
The (Web API) server has a breakpoint set in its corresponding Controller method, but it is never reached. As mentioned, the server is running, and responds just fine to other (Windows app) clients.
There must be a somewhat straightforward way of calling a RESTful method from Android. But what/how?
UPDATE
I tried this, now, too, calling it like so:
RestClient client = new RestClient("http://localhost:28642/api/Departments/GetCount");
try {
client.Execute(RestClient.RequestMethod.GET);
} catch (Exception e) {
e.printStackTrace();
}
String response = client.getResponse();
Log.i("CZECH_THIS", response);
...but it also is (or seems, anyway) happy to throw the "NetworkOnMainThread" exception.
UPDATE 2
This is the closest I've gotten so far, I think. Maybe the server is the culprit in this case, because with this code:
public void onFetchBtnClicked(View v){
if(v.getId() == R.id.FetchBtn){
Toast.makeText(getApplicationContext(), "You mashed the button, dude.", Toast.LENGTH_SHORT).show();
new CallAPI().execute("http://localhost:28642/api/Departments/GetCount");
}
}
public static class CallAPI extends AsyncTask<String, String, String> {
#Override
protected String doInBackground(String... params) {
String urlString=params[0]; // URL to call
String resultToDisplay = "";
InputStream in = null;
// HTTP Get
try {
URL url = new URL(urlString);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
in = new BufferedInputStream(urlConnection.getInputStream());
} catch (Exception e ) {
System.out.println(e.getMessage());
return e.getMessage();
}
return resultToDisplay;
}
protected void onPostExecute(String result) {
Log.i("FromOnPostExecute", result);
}
} // end CallAPI
....the exception that is thrown is:
libcore.io.ErrnoException: connect failed: ECONNREFUSED (Connection refused)
failed to connect to localhost/127.0.0.1 (port 28642): connect failed: ECONNREFUSED (Connection refused)
...and the Android app continues to run (it falls over in the other examples).
Why is my server refusing the connection?
UPDATE 3
I thought for a minute I had it: I forgot to pass the serial Num with the URL. But even after doing so, it fails.
I have a breakpoint in the server app, in the Controller method; also, in the Repository method, but they are never reached.
What could be wrong?
Is "localhost" the wrong thing to use (in the URL)? Should I use the name of the computer instead?
Does the URL (passed literally as "http://localhost:28642/api/Departments/GetCount?serialNum=4242") need to be verbatimized?
UPDATE 4
Changing the "locohost" to the machine name, I get "No address associated with hostname" so that's not the problem...
Oddly, though, this line runs fine:
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
...whereas this is the last line before the exception is thrown/caught:
in = new BufferedInputStream(urlConnection.getInputStream());
Looking at this, though, perhaps I need to escape my whacks; but when you already have double-whacks, as in after "http:", do you have to do triple-whacks? Or quadruple whacks? Surely not ceiling wax...?
I've got it working now. There's an article about it here.
This is the code from there without any explanation:
public class MainActivity extends ActionBarActivity {
private GetDepartmentsCount _getDeptsCount;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button getDeptsCountBtn = (Button)findViewById(R.id.DeptsCountBtn);
getDeptsCountBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
_getDeptsCount = new GetDepartmentsCount();
_getDeptsCount.execute("http://10.0.2.2:28642/api/Departments/GetCount?serialNum=4242");
}
});
}
#Override
public void onStop() {
super.onStop();
_getDeptsCount.cancel(true);
}
private class GetDepartmentsCount extends AsyncTask<String, String, String> {
#Override
protected String doInBackground(String... params) {
String urlString = params[0]; // URL to call
String result = "";
// HTTP Get
try {
URL url = new URL(urlString);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
if (null != inputStream)
result = IOUtils.toString(inputStream);
} catch (Exception e) {
System.out.println(e.getMessage());
return e.getMessage();
}
return result;
}
#Override
protected void onPostExecute(String result) {
EditText dynCount = (EditText)findViewById(R.id.dynamicCountEdit);
dynCount.setText(result + " records were found");
Log.i("FromOnPostExecute", result);
}
}
}
I am using ByteArrayOutputStream to put text in a Text View from an IputStream.
This works fine but...
I am from Sweden and when I put a text with some special Swedish letters it puts ? instead of the actual letter. The system have no problems with this letters otherwise.
Hope someone out there can give me a hint about what to do.
Perhaps I shall show the code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView helloTxt = (TextView)findViewById(R.id.hellotxt);
helloTxt.setText(readTxt());
}
private String readTxt(){
InputStream inputStream = getResources().openRawResource(R.raw.hello);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int i;
try {
i = inputStream.read();
while (i != -1)
{
byteArrayOutputStream.write(i);
i = inputStream.read();
}
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return byteArrayOutputStream.toString();
}
}
I also tied this, get it from the forum (Selzier):
Nice peace but still no Swedish letters in the output:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView tv = (TextView)findViewById(R.id.txtRawResource);
tv.setText(readFile(this, R.raw.saga));
}
private static CharSequence readFile(Activity activity, int id) {
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(
activity.getResources().openRawResource(id)));
String line;
StringBuilder buffer = new StringBuilder();
while ((line = in.readLine()) != null) buffer.append(line).append('\n');
return buffer;
}
catch (IOException e) {
return "";
}
finally {
closeStream(in);
}
}
/**
* Closes the specified stream.
*/
private static void closeStream(Closeable stream) {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
// Ignore
}
}
}
}
You are using the wrong encoding when you read/write the stream. Use UTF-8.
outputStream.toString("UTF8")
Edit: try this approach posted here. I think it can also be a issue if your file has a BOM. Use NotePad++ or another editor to remove it.
public static String readRawTextFile(Context ctx, int resId)
{
InputStream inputStream = ctx.getResources().openRawResource(resId);
InputStreamReader inputreader = new InputStreamReader(inputStream);
BufferedReader buffreader = new BufferedReader(inputreader);
String line;
StringBuilder text = new StringBuilder();
try {
while (( line = buffreader.readLine()) != null) {
text.append(line);
text.append('\n');
}
} catch (IOException e) {
return null;
}
return text.toString();
}