Dear People,
I´m working on a app to control my robot with bluetooth.
So i made a thread to handle the bluetooth device, and a handler to read the information in the Gui thread.
(See code below)
The problem is that i´m not able to print the information to the textview in the handler.
When i print somthing to the textview in de onCreate function, everythings works fine, but when i print something to the textview in the handler, nothing happens.
There are also no errors or something like that.
I know that the handler function is called, because the receive messages are printed well in the log.d.
I hope that there is anyone who can help me.
thanks in advance.
Tom
public class InteractionActivity extends Activity {
private ConnectThread mConnectThread;
private interface MessageConstants
{
public static final int MESSAGE_READ = 0;
public static final int MESSAGE_WRITE = 1;
public static final int MESSAGE_TOAST = 2;
}
@override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_interaction);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
BluetoothDevice device = getIntent().getExtras().getParcelable("btdevice");
((TextView) findViewById(R.id.textView5)).setText("Hallo"); // works fine, print correct to the screen
mConnectThread = new ConnectThread(device);
mConnectThread.start();
}
private final Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
byte[] writeBuf = (byte[]) msg.obj;
int begin = (int)msg.arg1;
int end = (int)msg.arg2;
String writeMessage = new String(writeBuf);
writeMessage = writeMessage.substring(begin, end);
((TextView) findViewById(R.id.textView5)).setText("Hallo1111"); //Nothing happens
Log.d(TAG, writeMessage); //is printed fine in the log
}
};
private class ConnectThread extends Thread {
etc ............
Related
I have a textview that shows your amount of money and i would like the ui to update every second to visually show how much money you have in real time. Would i be able to accomplish this with a timer?, and if so what would it look like.
Hello,
You should do inside your class, outside of any method:
Code:
TextView tv;
String calculatedString;
MyAsyncTask mAsync = null;
Timer timer = null;
TimerTask task = null;
private class MyAsyncTask extends AsyncTask<String, Void, String> {
public MyAsyncTask(){
}
@Override
protected String doInBackground(String... params) {
//Background operation in a separate thread
//Write here your code to run in the background thread
//calculate here whatever you like
calculatedString = ....;
return null;
}
@Override
protected void onPostExecute(String result) {
//Called on Main UI Thread. Executed after the Background operation, allows you to have access to the UI
tv.setText(calculatedString);
}
@Override
protected void onPreExecute() {
//Called on Main UI Thread. Executed before the Background operation, allows you to have access to the UI
}
}
inside the onCreate after super and setContentView:
Code:
tv = (TextView) findViewById(R.id.tv); //your tv id here
final Handler handler = new Handler();
timer = new Timer();
task = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
MyAsyncTask mAsync = new MyAsyncTask();
mAsync.execute();
}
});
}
};
timer.schedule(task, 0, 1000); //Every 1 second
If you still need help, feel free to ask
I have attached 2 screenshots showing the errors i was given after inputting. Any idea how to fix this?
mmdeveloper10 said:
Hello,
You should do inside your class, outside of any method:
Code:
TextView tv;
String calculatedString;
MyAsyncTask mAsync = null;
Timer timer = null;
TimerTask task = null;
private class MyAsyncTask extends AsyncTask<String, Void, String> {
public MyAsyncTask(){
}
@Override
protected String doInBackground(String... params) {
//Background operation in a separate thread
//Write here your code to run in the background thread
//calculate here whatever you like
calculatedString = ....;
return null;
}
@Override
protected void onPostExecute(String result) {
//Called on Main UI Thread. Executed after the Background operation, allows you to have access to the UI
tv.setText(calculatedString);
}
@Override
protected void onPreExecute() {
//Called on Main UI Thread. Executed before the Background operation, allows you to have access to the UI
}
}
inside the onCreate after super and setContentView:
Code:
tv = (TextView) findViewById(R.id.tv); //your tv id here
final Handler handler = new Handler();
timer = new Timer();
task = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
MyAsyncTask mAsync = new MyAsyncTask();
mAsync.execute();
}
});
}
};
timer.schedule(task, 0, 1000); //Every 1 second
If you still need help, feel free to ask
Click to expand...
Click to collapse
Hello,
For the first image:
You have to import the AsyncTask.
add this
Code:
import android.os.AsyncTask;
with the other imports in your java file.
For your second image:
You haven't wrote the line
Code:
setContentView(R.layout.activity_main);
under your super.onCreate(savedInstanceState); and then the code I said above (I said that on my post )
inside onCreate, where activity_main is your xml layout. And you should have inside that layout, a TextView with an id "tv" (or whatever you like)
and then:
Code:
tv = (TextView) findViewById(R.id.tv); //your tv id here
R.id.tv must much the id you have in your layout. Replace it with the actual id of your TextView. If your id is "tv", write R.id.tv, if it is "mytv" write R.id.mytv. ( I said that on my post also)
Can you show your layout file? (XML - your activity_main.xml). You said that you have a TextView Where is your TextView?
Ok I fixed the problems stated and now only have these two errors remaining
mmdeveloper10 said:
Hello,
For the first image:
You have to import the AsyncTask.
add this
Code:
import android.os.AsyncTask;
with the other imports in your java file.
For your second image:
You haven't wrote the line
Code:
setContentView(R.layout.activity_main);
under your super.onCreate(savedInstanceState); and then the code I said above (I said that on my post )
inside onCreate, where activity_main is your xml layout. And you should have inside that layout, a TextView with an id "tv" (or whatever you like)
and then:
Code:
tv = (TextView) findViewById(R.id.tv); //your tv id here
R.id.tv must much the id you have in your layout. Replace it with the actual id of your TextView. If your id is "tv", write R.id.tv, if it is "mytv" write R.id.mytv. ( I said that on my post also)
Can you show your layout file? (XML - your activity_main.xml). You said that you have a TextView Where is your TextView?
Click to expand...
Click to collapse
Have you imported this?
Code:
import java.util.logging.Handler;
If so, change it to
Code:
import android.os.Handler;
Im not at the computer but I think that should solve my issue I will keep you updated
Sent from my HTC6525LVW using XDA Free mobile app
Hey thanks so much its working perfectly now :good:
Hello!
i need some help, i am creating a Grid View with this java code:
MainActivity
public class MainActivity extends AppCompatActivity {
private GridView gridView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gridView = (GridView)findViewById(R.id.gridview);
gridView.setAdapter(new GridAdapter(this));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Click to expand...
Click to collapse
Product
public class Product {
private static String nombrePizza;
private static String ingredientesPizza;
private static int imagenPizza;
private static int idThumbnail;
public Product(String nombrePizza, String ingredientesPizza, int imagenPizza){
this.nombrePizza = nombrePizza;
this.ingredientesPizza = ingredientesPizza;
this.imagenPizza = imagenPizza;
}
public String getNombrePizza(){return nombrePizza;}
public String getIngredientesPizza(){return ingredientesPizza;}
public int getImagenPizza(){return imagenPizza;}
public int getId(){return nombrePizza.hashCode();}
public static Product[] Pizzas={
new Product(
"Proscuito",
"Jamon York y queso",
R.drawable.imagenprueba),
new Product(
"Tropical",
"Jamon York, queso y piña",
R.drawable.imagenprueba),
new Product(
"Barbacoa",
"Carne picada, queso y salsa Barbacoa",
R.drawable.imagenprueba),
new Product(
"Romana",
"Jamon York, champiñones y queso",
R.drawable.cubo),
};
public static Product getItem(int id) {
for (Product item : Pizzas) {
if (item.getId() == id) {
return item;
}
}
return null;
}
}
Click to expand...
Click to collapse
Grid Adapter
public class GridAdapter extends BaseAdapter {
private final Context mContext;
public GridAdapter(Context c){
this.mContext = c;
}
@Override
public int getCount(){return Product.Pizzas.length;}
@Override
public Product getItem(int position){return Product.Pizzas[position];}
@Override
public long getItemId(int position){return 0;}
@Override
public View getView(int position, View ConvertView, ViewGroup viewGroup){
if(ConvertView == null){
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ConvertView = inflater.inflate(R.layout.grid_item, viewGroup, false);
}
TextView name = (TextView)ConvertView.findViewById(R.id.grid_mainText);
ImageView image = (ImageView) ConvertView.findViewById(R.id.grid_image);
TextView descripcion = (TextView) ConvertView.findViewById(R.id.grid_subText);
final Product item = getItem(position);
image.setImageResource(item.getImagenPizza());
name.setText(item.getNombrePizza());
descripcion.setText(item.getIngredientesPizza());
return ConvertView;
}
}
Click to expand...
Click to collapse
It work fine except for one thing, the app only shows the last product of the java code (Pizza romana)four times
I dont know why my app do this, can somebody help me??
Thank you! :fingers-crossed:
So I was programming in some In app Billing code for my Android app using Android Studio. I was following an Android tutorial called 'Preparing your In-app Billing Application' at the Android Developer website (not allowed to give a link because I'm a new user). All was going well, until I get to the part where I have to paste their code into my code. Check out their code put into mine (I left the base64EncodedPublicKey empty so nobody would steal it):
Code:
public class MainActivity extends ActionBarActivity {
//Add other java files to the main class
private JokeBook mJokeBook = new JokeBook();
private ColorWheel mColorWheel = new ColorWheel();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Declare View variables
final TextView jokeLabel = (TextView) findViewById(R.id.jokeTextView);
final Button showJokeButton = (Button) findViewById(R.id.showJokeButton);
final RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.relativeLayout);
final Button moreJokes = (Button) findViewById(R.id.moreJokes);
//On Click
View.OnClickListener listener = new View.OnClickListener() {
@Override
public void onClick(View v) {
String joke = mJokeBook.getJoke();
//Update label with fact
jokeLabel.setText(joke);
int color = mColorWheel.getColor();
relativeLayout.setBackgroundColor(color);
showJokeButton.setTextColor(color);
moreJokes.setTextColor(color);
}
};
showJokeButton.setOnClickListener(listener);
goToTwitter();
goToFacebook();
goToExxellerate();
IabHelper mHelper;
@Override
public void [U]onCreate(Bundle savedInstanceState)[/U] {
// ...
String base64EncodedPublicKey = "";
// compute your public key and store it in base64EncodedPublicKey
[B]mHelper = new IabHelper(this, base64EncodedPublicKey);[/B]
}
mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
public void onIabSetupFinished(IabResult result) {
if (!result.isSuccess()) {
// Oh noes, there was a problem.
[I]Log.d(TAG, "Problem setting up In-app Billing: " + result);[/I]
}
// Hooray, IAB is fully set up!
}
});
@Override
public void [U]onDestroy()[/U] {
super.onDestroy();
if (mHelper != null) mHelper.dispose();
mHelper = null;
}
}
The code that they gave me had many errors when pasted into Android Studio, which were:
TAG has private access in 'android.support.v4.app.FragmentActivity' (Italicized text)
Annotations are not allowed here (@Override)
; expected (Underlined text)
IabHelper (android.view.View.onClickListener, String) in IabHelper cannot be applied to (com.exxellerate.joketeller.MainActivity, String) (Bolded Text)
Any help with fixing there errors? I'm a beginner at code and very confused that the code they gave me was wrong...
Hey ladies and gents,
I'm new to your forums, seems it will be a helpful resource as I undertake this new project. I'm not new to programming, but i'm rusty. About 20 years ago I started with Qbasic, in high school i moved on to Visual Studio and C++. But I have been out of it for awhile now.
I started learning a little python to help my dad with his own program. But Decided I wanted to use Android Studio for my own. I have already started looking into tutorials, but have yet to see some information I am looking for. ( Or just don't recognize due to inexperience )
Traditionally, whats best to use for a multiscreen App? I am currently running windows in Fragments. I have a sidescreen that pops out with a menu button (works), windows slide out with options ( works ), when you select the option the window slides away (works) and it brings up the fragment so you can fill in forms (works.)
Inside my Fragments java file I have this
public class ac extends Fragment {
private EditText od_input;
private EditText sp_input;
private EditText hp_input;
private EditText sl_input;
private EditText hl_input;
private EditText return_input;
private EditText vent_input;
private TextView diag_output;
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public ac() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment ac.
*/
// TODO: Rename and change types and number of parameters
public static ac newInstance(String param1, String param2) {
ac fragment = new ac();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
EditText odtext;
EditText idtext;
EditText sptext;
EditText hptext;
EditText sltext;
EditText hltext;
EditText returntext;
EditText venttext;
@override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_ac, container, false);
// NOTE : We are calling the onFragmentInteraction() declared in the MainActivity
// ie we are sending "Fragment 1" as title parameter when fragment1 is activated
if (mListener != null) {
mListener.onFragmentInteraction("Air Conditioning");
}
// Here we will can create click listners etc for all the gui elements on the fragment.
// For eg: Button btn1= (Button) view.findViewById(R.id.frag1_btn1);
// btn1.setOnclickListener(...
//odtext = view.findViewById(R.id.odtext);
//idtext = (EditText) findViewById(R.id.idtext);
//sptext = view.findViewById(R.id.sptext);
//hptext = view.findViewById(R.id.hptext);
//sltext = view. findViewById(R.id.sltext);
//hltext = view.findViewById(R.id.hltext);
//returntext = view.findViewById(R.id.returntext);
//venttext = view.findViewById(R.id.venttext);
//TextView diagtext = view.findViewById(R.id.diagtext);
//diagtext.setText((CharSequence) odtext);
return view;
}
@override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// NOTE : We changed the Uri to String.
void onFragmentInteraction(String title);
}
}
Firstly, yes there is a lot of useless crapification going on. Was running different experiments and have not fully cleaned up yet.
But, as people type in the field I want to capture the inputs. Does this require a Listener? Can you capture as they type or do I need a button (Really, Really don't want a button)?
Also, I am unfamiliar with the layout of the java.
Oncreate is when the program boots up?
onCreateview is when the Fragment is booted up?
onattach is when the main activity is associated?
ondetach is when its associated from activity?
I don't fully understand yet where the best place is to add stuff, would it be after onattach?
Thanks for pointing me in the right directions guys.
Chris W.
I want to send mail from Navigation Drawer using the intent. First, my MainActivity.
Code:
else if(id==R.id.nav_mail) {
fragment = new MailFragment();
}
and MailFragment.
Code:
public class MailFragment extends Fragment {
public MailFragment() {
Intent email = new Intent(Intent.ACTION_SEND);
email.setType("plain/text");
String[] address = {"********@gmail.com"};
email.putExtra(Intent.EXTRA_EMAIL, address);
email.putExtra(Intent.EXTRA_SUBJECT, "Subject___****");
email.putExtra(Intent.EXTRA_TEXT, "Text___****.\n\n");
startActivity(email);
}
// @Override
// public View onCreateView(LayoutInflater inflater, ViewGroup container,
// Bundle savedInstanceState) {
// TextView textView = new TextView(getActivity());
// textView.setText(R.string.hello_blank_fragment);
// return textView;
// }
}
Run to create crash. The reason why I used to use fragment is because I made the simple screen change function fragment.
If you need more code, comment plz.
I didn't get what you are trying to do. If you are trying to invoke the "Select your mail app" screen and then send a message thru the Intent all of this when the user clicks on a row on the drawer then you should just copy the code to
Code:
else if(id==R.id.nav_mail) {
// here
}
without switching any fragment.
By the way, as far as I know, the fragment's public constructor must be empty.
You cannot do it from Fragment's constructor. Move your code to onActivityCreated() method.
qlife1146 said:
I want to send mail from Navigation Drawer using the intent. First, my MainActivity.
Code:
else if(id==R.id.nav_mail) {
fragment = new MailFragment();
}
and MailFragment.
Code:
public class MailFragment extends Fragment {
public MailFragment() {
Intent email = new Intent(Intent.ACTION_SEND);
email.setType("plain/text");
String[] address = {"********@gmail.com"};
email.putExtra(Intent.EXTRA_EMAIL, address);
email.putExtra(Intent.EXTRA_SUBJECT, "Subject___****");
email.putExtra(Intent.EXTRA_TEXT, "Text___****.\n\n");
startActivity(email);
}
// @Override
// public View onCreateView(LayoutInflater inflater, ViewGroup container,
// Bundle savedInstanceState) {
// TextView textView = new TextView(getActivity());
// textView.setText(R.string.hello_blank_fragment);
// return textView;
// }
}
Run to create crash. The reason why I used to use fragment is because I made the simple screen change function fragment.
If you need more code, comment plz.
Click to expand...
Click to collapse
Creating a new Intent in the constructor is a really bad idea. An example from the android's developer guide
Code:
public class MainActivity extends AppCompatActivity {
public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/** Called when the user taps the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.editText);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}