Develop Reference

How to program 2 function C button in calculator?

I'm a beginner in Android Studio, and I want to make a C button in calc with 2 functions.
How do I do that on one tap the C button erases only one number, and on hold erase all numbers in TextView?
findViewById(R.id.btnClear).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
txtScreen.setText(""); // Clear the screen
// Reset all the states and flags
lastNumeric = false;
stateError = false;
lastDot = false;

You can set an onClickListener and onLongClickListener to achieve this.
cButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String currentText = textView.getText().toString();
if(currentText.length >= 2){
currentText = currentText.substring(0, currentText.length - 2);
}else{
currentText = "";
}
textView.setText(currentText);
}
});
cButton.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
textView.setText("");
return true;
}
});

Have you looked in to the onClick() and onLongPress() methods?
cancelButton.setOnLongClickListener(new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
myTextView.setText("");
return true;
}
});
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
removeOneCharacter();
}
});
private void removeOneCharacter()
{
String textViewValue = myTextView.getText().toString();
if (textViewValue != null && textViewValue.length >= 2)
{
myTextView.setText(textViewValue.substring(0, textViewValue.length() - 2);
}
}
The onClick() method removes on char from the TextView at a time. The onClick() method however removes the entire String from the TextView but only considering if there is already 2 or more characters to prevent an Exception from occurring due to the upper-bound of the substring.
An improvement here could be to add another if function that checks the character length within the Long press and performs a clear if there is only one character remaining.

Edittext Focus and click

I have Two EditTexts. I want On First EditTexts click clear the second and on second edittext click clear the first one. So I have tried OnClickListener and OnTouchListener. But it is not working properly.
et_email.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (!(et_email.getText().toString().equalsIgnoreCase("") && et_mobile.getText().toString().equalsIgnoreCase(""))) {
if (MotionEvent.ACTION_UP == event.getAction()) {
et_mobile.setText("");
et_mobile.setFocusableInTouchMode(true);
et_mobile.setFocusable(true);
et_mobile.requestFocus();
}
return true; // return is important...
} else
return false;
}
});
et_mobile.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (!(et_email.getText().toString().equalsIgnoreCase("") && et_mobile.getText().toString().equalsIgnoreCase(""))) {
if (MotionEvent.ACTION_UP == event.getAction()) {
et_email.setText("");
et_mobile.setFocusableInTouchMode(true);
et_mobile.setFocusable(true);
et_mobile.requestFocus();
}
return true; // return is important...
}
else
return false;
}
});
But the problem is Focus is not setting on first touch and while clicking and unable to clear EditText.

First add this to your Edittext layouts:
android:focusableInTouchMode="false"
Without this line, the EditText will react to touch-mode, and only listen to your onClick() the second time you click your EditText bar.
This will disable touch-mode for EditText, and fire onClick() in first time
focusableInTouchMode
Note: boolean that controls whether a view can take focus while in touch mode. If this is true for a view, that view can gain focus when clicked on, and can keep focus if another view is clicked on that doesn't have this attribute set to true.
than do as follows:
EditText1
EditText et_email = (EditText) findViewById(R.id.yourEditText1);
et_email.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//do this
et_mobile.setText("");
//or this
et_mobile.getText().clear();
}
});
EditText2
EditText et_mobile = (EditText) findViewById(R.id.yourEditText2);
et_mobile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//do this
et_email.setText("");
//or this
et_email.getText().clear();
}
});
This should help u out.

you are clearing the first one one touching the first one, change your variable names in first listener like this
if (!(et_email.getText().toString().equalsIgnoreCase("") && et_mobile.getText().toString().equalsIgnoreCase(""))) {
if (MotionEvent.ACTION_UP == event.getAction()) {
et_mobile.setText("");
et_email.setFocusableInTouchMode(true);
et_email.setFocusable(true);
et_email.requestFocus();
}
return true; // return is important...
} else

I hope this code helps you (it works for me)
edit1 = (EditText) findViewById(R.id.edit1);
edit2 = (EditText) findViewById(R.id.edit2);
edit1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
edit2.setText("");
}
});
edit2.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
edit1.setText("");
}
});

Set focus on spinner when selected in android

I have a vertical scrolling layout with multiple EditText and Spinner controls.
Problem is when i choose any spinner option after selection the screen scrolls back to the last EditText is was editing before this spinner. The Focus remains with the last EditText i was editing. Is there a way i can keep focus with the current selected spinner.
I am looking for a solution that can be implemented on all spinners from layout XML or some generic method to apply to all spinners.

Here's my solution.
mSpinner.setFocusableInTouchMode(true);
mSpinner.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus) {
if (mSpinner.getWindowToken() != null) {
mSpinner.performClick();
}
}
}
});

Use this to avoid EditText Focus :
scrollView = (ScrollView) findViewById(R.id.scrollView_id);
scrollView.setOnTouchListener(new OnTouchListener() {
// to solve foocus problem on scrolling
public boolean onTouch(View v, MotionEvent event) {
if (myEditText.hasFocus()) {
myEditText.clearFocus();
}
if (myEditText1.hasFocus()) {
myEditText1.clearFocus();
}
return false;
}
});

I solved the problem with the help of Ryderz answer. here is the code :
InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
scrollView = (ScrollView) findViewById(R.id.sv_main);
scrollView.setOnTouchListener(new OnTouchListener() {
// to solve focus problem on scrolling
public boolean onTouch(View v, MotionEvent event) {
IBinder windowToken = null;
if (myEditText1.hasFocus()) {
myEditText1.clearFocus();
windowToken = myEditText1.getWindowToken();
}
if (myEditText2.hasFocus()) {
myEditText2.clearFocus();
windowToken = myEditText2.getWindowToken();
}
if (myEditText3.hasFocus()) {
myEditText3.clearFocus();
windowToken = myEditText3.getWindowToken();
}
if (windowToken != null) {
imm.hideSoftInputFromWindow(windowToken, 0);
}
scrollView.requestFocusFromTouch();
return false;
}
});
Then I set the android:focusable="true" for my textViews so that on scroll when focus is removed from editText then the Textviews can be picked for focus. In that way the user doesn't see any focused control on screen.

I had the same problem like you and I've resolved with this solution.
I've redefined OnItemSelectedListener and when the spinner changes the value, I take the focus and after that, I release again.
This is my class CustomOnItemSelectedListener:
public class CustomOnItemSelectedListener implements AdapterView.OnItemSelectedListener{
private Spinner mSpinner;
private int iCurrentSelection;
public CustomOnItemSelectedListener(Spinner s){
mSpinner = s;
iCurrentSelection = mSpinner.getSelectedItemPosition();
}
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
if (iCurrentSelection != arg2) {
mSpinner.setFocusableInTouchMode(true);
mSpinner.requestFocus();
mSpinner.setFocusableInTouchMode(false);
mSpinner.clearFocus();
}
iCurrentSelection = arg2;
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
//No hace falta hacer nada
}
}
In my code I do this
Spinner spinner = (Spinner) rootView.findViewById(R.id.spinner);
spinner.setOnItemSelectedListener(new CustomOnItemSelectedListener(spinner));
If you want to keep focus, don't do "clearFocus()".

Custom EditText validation

i am creating my custom EditText which validate email and other things on focus lost and if it is not valid then focus back. It works fine if i have only one EditText but when i have multiple EditText it infinity focuses between my editText boxes as it try to check validation in both. Here is my sample code.
public void init(){
this.setOnFocusChangeListener(new OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
// TODO Auto-generated method stub
final MyEditText ed = MyEditText.this;
//...............check require field validation
if(!hasFocus && isRequire){
if(ed.getText().toString().length()<=0){
String msg = "Require Field";
v.clearFocus();
setErrorMsg(ed,msg);
return;
}
}else if(ed.getText().toString().length()>0){
ed.setError(null);
}
}
}
private void setErrorMsg(final EditText ed,String msg){
if(errorMessage!=null && errorMessage.length()>0){
msg = errorMessage;
}
ed.setError(msg);
ed.post(new Runnable() {
public void run() {
ed.requestFocus();
}
});
}

Put onfocus change lisner on the parent view from the viewGroup get the child view and chek it u will get the perticular edittext. i had some requirement like that i solved it this way.
TableLayout tableView = (TableLayout)findViewById(R.id.mydetails_tableview);
View mytempView=null;
int noOfChilds=tableView.getChildCount();
for(int i=0;i<noOfChilds;i++)
{
mytempView=tableView.getChildAt(i);
if(i%2==0)
{
View vv=((TableRow) mytempView).getChildAt(1);
if(vv instanceof EditText)
{
//Log.v("This one is edit text---", "here there");
((EditText) vv).setText("");
}
}
}

boolean pendingFocus = false;
Before
ed.post(new Runnable() {
public void run() {
ed.requestFocus();
}
});
Add
pendingFocus = true;
and Replace:
if(!hasFocus && isRequire){
with
if(!hasFocus && isRequire && !pendingFocus){
Finally reset pendingFocus with a new else statement here:
if(ed.getText().toString().length()<=0){
String msg = "Require Field";
v.clearFocus();
setErrorMsg(ed,msg);
return;
}
}else if(ed.getText().toString().length()>0){
ed.setError(null);
}else{
pedingFocus = false;
}

How can I detect focused EditText in android?

I have a number of EditText elements in my page along with two buttons. I want the user to touch on any one EditText field and click any button to insert a certain value into that very EditText field they touched. Giving input using the keypad is not allowed. Please help me to do this.

You can use View.OnFocusChangeListener to detect if any view (edittext) gained or lost focus.
for (EditText view : editList){
view.setOnFocusChangeListener(focusListener);
}
....
private OnFocusChangeListener focusListener = new OnFocusChangeListener() {
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus){
focusedView = v;
} else {
focusedView = null;
}
}
}
This goes in your activity or fragment or wherever you have the EditTexts. The .... is just saying that you can put it anywhere else in the class. And obviously you would need to create an array with them in it, thus the editList.

This works for me. It returns a boolean.
myEditText.hasFocus()

One thing that you can do is declare a global variable evalue which will tell you which is the last selected EditText by using onTouchListener and then based on the value of evalue, you can set the text value to the edittext by button click. hope you understood.
the code for it can be as follow:
EditText e1,e2;
Button b1,b2;
String evalue;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
e1=(EditText)findViewById(R.id.editText1);
e2=(EditText)findViewById(R.id.editText2);
b1=(Button)findViewById(R.id.button1);
b2=(Button)findViewById(R.id.button2);
e1.setOnTouchListener(new View.OnTouchListener()
{
public boolean onTouch(View arg0, MotionEvent arg1)
{
evalue="1";
return false;
}
});
e2.setOnTouchListener(new View.OnTouchListener()
{
public boolean onTouch(View arg0, MotionEvent arg1)
{
evalue="2";
return false;
}
});
b1.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
if(evalue=="1")
{
e1.setText("yes");
}
if(evalue=="2")
{
e2.setText("yes");
}
}
});
b2.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
if(evalue=="1")
{
e1.setText("No");
}
if(evalue=="2")
{
e2.setText("No");
}
}
});
}
Its a logical coding.. not upto the mark.. if you find a better one. then use it. thank you.

This worked for me.
e1 = (EditText) findViewById(R.id.editText1);
e1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View arg0, boolean hasfocus) {
if (hasfocus) {
Log.e("TAG", "e1 focused")
} else {
Log.e("TAG", "e1 not focused")
}
}
});

With Java 8 lambdas:
EditText editTextTo = findViewById(R.id.editTextTo);
editTextTo.setOnFocusChangeListener((view, b) -> {
if (view.isFocused()) {
// Do whatever you want when the EditText is focused
// Example:
editTextFrom.setText("Focused!");
}
});
Note that the view inside the lambda function is actually an instance of an EditText.

Have your Fragment implement OnTouchListener & OnFocusChangeListener:
public class AttributesFragment extends Fragment
implements OnTouchListener, OnFocusChangeListener {
Then implement using:
#Override
public boolean onTouch(View view, MotionEvent event) {
if (view instanceof EditText) {
view.setOnFocusChangeListener(this); // User touched edittext
}
return false;
}
#Override
public void onFocusChange(View v, boolean hasFocus) {
}
Don't forget to set your listener after creating your EditText
editText.setOnTouchListener(this);
This way if an EditText box is focused by default but user has not changed the field it will not fire the onFocusChange event.

Simple Coding:
if(EditText1.isFocused()){
//EditText1 is focused
}else if(EditText2.isFocused()){
//EditText2 is focused
}

This worked for me using Java 8 (lambdas):
EditText myEditText = findViewById(R.id.editText);
myEditText.setOnFocusChangeListener((view, hasFocus) -> {
if(hasFocus){
Log.e("TAG", "myEditext has focus")
}else{
Log.e("TAG", "myEditext has no focus")
}
});

In your activity or fragment implement OnFocusChangeListener.
edittextNeme= (EditText) findViewById(R.id.edittextNeme);
edittextNeme.setOnFocusChangeListener(this);
You will have to check which view changed focus by getting the view id with view.getId() and handle accordingly.
#Override
public void onFocusChange(View view, boolean hasfocus) {
switch(view.getId()){
case R.id.edittextNeme:
//Do something
break;
...etc
}
}

val currentFocusView = activity.currentFocus
if (currentFocusView is EditText){
currentFocusView.appendText("Has Focus!")
}