We Keep Coding

How can I use interface from a for loop

I have two inner classes named CalculatorClass and UpdatePayment in MainActivity class.
In UpdatePayment class there is a for loop and I have a array of Buttons.
I want to add listener to each button in loop. Those buttons will initialize the CalculatorClass and get value of calculations.
Demo code is:
public static class MainActivity{
private interface UpdateEditText{
void onCallback(String s);
}
private class CalculatorClass extends Dialog{
UpdateEditText updateEditText;
public CalculatorInterface(#NonNull Context context, UpdateEditText updateEditText) {
super(context);
this.updateEditText = updateEditText;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.calculator);
initialize();
}
initialize(){
.......................
s = "Some texts";
updateEditText.onCallback(s);
}
}
private class UpdatePayment extends Dialog{
private Button[] button = new Button[100];
private EditText[] editText = new EditText[100];
public CalculatorInterface(#NonNull Context context) {
super(context);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.update);
initialize();
}
initialize(){
.......................
for(int i = 0; i < MAXSize; i++){
button[i] = new Button(MainActivity.this);
editText[i] = new EditText(MainActivity.this);
//add buttons to view to layout
button[i].setOnclickListener(new View.OnClickListener(){
public void onClick(View v) {
CalculatorClass calculator = new
CalculatorClass(MainActivity.this,
new UpdateEditText() {
#Override
public void onCallback(String s) {
editText[i - 1].setText(s);
}
});
calculator.show();
}
);
}
}
}
}
Problem is the line editText[i].setText(s) work for the last editText what ever button I click, i.e, any button I click, it fills the editText[MaxSize -1]
What should I do?
How can I perform this action for all i?
Please help me, I tried a lot searching in internet, still I didn't get any solution.

Anonymous classes are very much treated like static variables in java.It's happenning because your i value after your activity is initialized is equal to 1 less than the length of the edit text array.
editText[indicies_of_button_clicke].setText(s)
How you will get the indicies of button clicked is by :
se the tag to button below this line "editText[i] = new EditText(MainActivity.this);", like this :
button[i].setTag(i)
to retreive the index of your actual button clicked inside button clicklisteners,
v.getTag()// this will give you an integer value which will be the indices of actual button clicked
//use this value to set your edit text value.

Solution:
After a whole night, I got answer, now I feel awwww, this was easy go!
I never came in this thought.
button[i].setId(i);
then call:
CalculatorClass calculator = new CalculatorClass(MainActivity.this, v.getId(),
new UpdateEditText() {
#Override
public void onUpdate(String s, int ID) {
Log.i("test", ID + "");
editText[ID].setText(s);
}
});
At the same time, #Rishabh Ritweek answered correctly.
Thanks to him.

Wait for completion of a calculation without UI freeze

I am trying to implement a search function in an Android app that takes text from an AutoCompleteTextView, waits if there hasn't been made a change in the last 1.5 seconds and shows the search results. For this I use the TextWatcher class.
However, all my tries to implement this behavior ran into trouble with some functions only being allowed in the UI thread itself (via runOnUIThread) or the thread having Looper.prepare() called before.
In all attempts, the app crashes randomly when entering additional characters or deleting some, does not show any search results or reload to the start activity.
The following is a simplyfied recreation of my most recent try, where I use a Handler.
search.getResults is the long computation and matches is an array that has to be filled before delayableAdapterCreation creates the ArrayAdapterWithSpaceFilter.
public class SearchFragment extends Fragment {
public final static int MAX_NUMBER_OF_SUGGESTIONS = 4; // only show a max of 4 suggestions if more were found
public final static int SEARCH_CHAR_AMOUNT = 3; // only search if at least 3 characters were typed
public final static long SEARCH_DELAY_MILLIS = (long) 1500; // the time to wait for no text changes in milliseconds
private Search search;
private AutoCompleteTextView textView;
private String[] matches;
private String userStartRequest;
private Entry[] suggestions;
private FragmentListenter sListener;
private EntryFunctions ef = new EntryFunctions();
private Runnable delayableSearch;
private Runnable delayableAdapterCreation;
private Handler delayableSearchHandler;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
delayableSearchHandler = new Handler();
delayableSearch = new Runnable() {
#Override
public void run() {
userStartRequest = textView.getText().toString();
sListener.onFragmentFinish(userStartRequest);
suggestions = search.getResults(userStartRequest);
matches = ef.fillMatches(suggestions);
}
};
delayableAdapterCreation = new Runnable() {
#Override
public void run() {
ArrayAdapterWithSpaceFilter<String> adapter =
new ArrayAdapterWithSpaceFilter<String>(getActivity(),
android.R.layout.simple_list_item_1,
matches);
textView.setAdapter(adapter);
}
};
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_search, container, false);
}
#Override
public void onStart() {
super.onStart();
textViewHandler();
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (!(context instanceof FragmentListenter)) throw new AssertionError();
sListener = (FragmentListenter) context;
}
/**
* Interface for communicate to activity
*/
public interface FragmentListenter {
void onFragmentFinish(String userStartRequest);
}
/**
* Handler for the AutoCompleteTextView
*/
private void textViewHandler() {
try {
textView = (AutoCompleteTextView) getView().findViewById
(R.id.startNaviAutoCompleteTextView);
search = new Search();
System.out.println("Created Search object");
textView.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
System.out.println("TextWatcher beforeTextChanged");
}
#Override
public void onTextChanged(CharSequence s, final int start, int before, int count) {
delayableSearchHandler.removeCallbacks(delayableSearch); userStartRequest = textView.getText().toString();
sListener.onFragmentFinish(userStartRequest);
if (textView.getText().length() >=
SEARCH_CHAR_AMOUNT) {
new Thread(delayableSearch).start();
delayableSearchHandler.postDelayed
(delayableAdapterCreation, SEARCH_DELAY_MILLIS);
}
}
#Override
public void afterTextChanged(Editable s) {
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
At this point, it does not matter to me, whether the calculation already starts whenever a new character is typed into the AutoCompleteTextView and an eventual old search is canceled or the search starts after the 1.5 seconds.
The above code does crash if the search term yields no results and there are problems with the results list. Sometimes it shows up for what has been entered a few keystrokes ago (so if I search for abcd slowly I get search results for abc), sometimes it doesn't show up at all. My guess would be a race condition or some problem with calling the textViewHandler or onTextChanged methods multiple times, even though delayableSearchHandler.removeCallbacks(delayableSearch) should prevent this from happening.
Can anyone explain, what the interaction between the worker thread and the UI thread would have to look like, so it is guaranteed that the search delivers it's results?
Thanks in advance,
Joe

Any long running operation (Network call, database search...) can take long time to execute thus blocking the UI. Prior to Ice cream sandwich this kind of behavior was tolerated by the android runtime.
This article might be a good read

Using onSaveInstanceState during orientation change?

First thing; I'm pretty much brand new to all this.
I've built a basic calculator but I lose the data when switching orientation (such as typing the number 9 then it going blank when switched to landscape).
I've already looked and found this:
How to use onSavedInstanceState example please
, but I'm unsure how to implement it into my code.
public class MainActivity extends AppCompatActivity {
private TextView _screen;
private String display = "";
private String currentOperator = "";
private String result = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
_screen = (TextView)findViewById(R.id.textView);
_screen.setText(display);
}
private void updateScreen(){
_screen.setText(display);
}
Can anyone help? An example using my piece would be perfect. Thanks

android - set intent extra from inside runnable

I'm still new to android development. I've been at this problem for some time but am still unable to figure out what to do on my own. In an Activity I set up a series of Runnables containing CountDownTimers. One executes after the next, but depending on which CountDownTimer is active, I need to pass a different Intent.extra to a fragment. I've tried setting my extra from inside Runnable, inside Run, and inside of the CountDownTimer onTick, and onFinish.
I fear I have way too much going on in my original Activity to post it, but here is the problem in essence.
public class MatchUpActivity extends Activity implements OpponentFragment.OnFragmentInteractionListener{
List mTotalDrafts;
Bundle mBundle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_match_up);
mBundle = new Bundle();
mDraftUsernames = extras.getStringArrayList("DRAFT_LIST");
for (int i = 0; i < totalDrafts; i++) {
Handler delayhandler = new Handler();
delayhandler.postDelayed(new Runnable() {
//bundle.put("extra", totalDrafts.get(0))
public void run() {
//bundle.put("extra", totalDrafts.get(0))
getTimer();
}
}, mTodaysDraftTime + (i * singleDraftDuration) - Calendar.getInstance().getTimeInMillis());
}
}
CountDownTimer
private void getTimer() {
new CountDownTimer(singleDraftDuration, 1000) {
public void onTick(long millisUntilFinished) {
//bundle.put("extra", totalDrafts.get(0))
}
public void onFinish() {
//bundle.put("extra", totalDrafts.get(0))
list.remove(0)
}
}.start();
}
}
I am able to remove items from my list in onFinish, but after I do so I need to send the next element in the list as an extra.
I hope this is enough code to get my question across. I tried to change some things from my original code for simplicity. If there is something I am missing or a better way to do this, please, anybody let me know.

Define the Bundle as global variable in your Activity and not in a Method implementation.

Moving logic from MainActivity to another class in Android

I have a simple logic on my app that looks for a certain pitch.
The problem is that the logic is in the OnCreate method of the app (it has to detect the pitch the moment the application is running).
It is a little bit ugly as I plan to add some more logic as the application starts.
Does anyone have any advice of how to move that code to a different class so that it could be invoked from there?
The class still has to access views in the main activity.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AudioDispatcher dispatcher = AudioDispatcherFactory.fromDefaultMicrophone(22050,1024,0);
dispatcher.addAudioProcessor(new PitchProcessor(PitchEstimationAlgorithm.FFT_YIN, 22050, 1024, new PitchDetectionHandler() {
#Override
public void handlePitch(PitchDetectionResult pitchDetectionResult,
AudioEvent audioEvent) {
final float pitchInHz = pitchDetectionResult.getPitch();
runOnUiThread(new Runnable() {
#Override
public void run() {
Float value = pitchInHz;
Toast.makeText(getApplicationContext(),value.tostring(), Toast.LENGTH_SHORT).show();
}
});
}
}));
foo = new Thread(dispatcher,"Audio Dispatcher");
foo.start();
}

Basically, you have two options to make your code cleaner.
Move all the code in onCreate() (except first two lines) into another method, let's say lookForPitch(). Then you can call it right in onCreate().
If you plan to create more methods that focus on audio processing, you can create separate class, for example AudioUtils.java. This util class should contain public static methods, that you can invoke from any place in your code. In case of onCreate() you may call it like this: AudioUtils.lookForPitch(). Also if you want to handle Views, that are accessible only in your Activity, you can pass them as argument. So your method in AudioUtils can look like this:
public static void lookForPitch(TextView myTextView) {
// your code goes here
}

Just make it a method
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myLongAndSweetMethod();
}
private void myLongAndSweetMethod(){
AudioDispatcher dispatcher = AudioDispatcherFactory.fromDefaultMicrophone(22050,1024,0);
dispatcher.addAudioProcessor(new PitchProcessor(PitchEstimationAlgorithm.FFT_YIN, 22050, 1024, new PitchDetectionHandler() {
#Override
public void handlePitch(PitchDetectionResult pitchDetectionResult,
AudioEvent audioEvent) {
final float pitchInHz = pitchDetectionResult.getPitch();
runOnUiThread(new Runnable() {
#Override
public void run() {
Float value = pitchInHz;
Toast.makeText(getApplicationContext(),value.tostring(), Toast.LENGTH_SHORT).show();
}
});
}
}));
foo = new Thread(dispatcher,"Audio Dispatcher");
foo.start();
}
Then using the Code folding of Android Studio to hide it.

If you want to improve the readability of your code I can recommend the book "Clean Code: A Handbook of Agile Software Craftmanship" by Robert C. Martin (aka Uncle Bob).
This book is really great! It helped me to a lot to make my code more clean and easy to read. It is a book you should have read if you want to be(come) a professional software developer.