Develop Reference

Is there a way to display text as you type in Android Studio?

Is there a way to display text on screen automatically as you type an input in a text field in Android Studio?
For example, if I type in a number, it gets automatically multiplied by 20 and the result is shown on the screen below the text field.

One simple way is to use on Textview Event listeners to handle your actions!
here is how u can do it.
field1 = (EditText)findViewById(R.id.field2);
field1.addTextChangedListener(new TextWatcher()
{
public void afterTextChanged(Editable s)
{ //Called after the changes have been applied to the text.
//You can change the text in the TextView from this method.
}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
//Called before the changes have been applied to the text.
}
public void onTextChanged(CharSequence s, int start,int before, int count) {
TextView.setText("Here is the changing text"+s);
//Similar to the beforeTextChanged method but called after the text changes.
}
});
/*
You can prevent an infinite loop like this
#Override
public void afterTextChanged(Editable s) {
if (_ignore)
return;
_ignore = true; // prevent infinite loop
// Change your text here.
// myTextView.setText(myNewText);
_ignore = false; // release, so the TextWatcher start to listen again.
}
*/

I could not understand the question properly so here is the solution for the 2 different cases.
The text to display is in the same Activity or Fragament.
Use a TextWatcher class like this
et1.addTextChangedListener(new TextWatcher() {
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
//This method is called to notify you that, within s, the count characters beginning at start have just replaced old text that had length before.
newTextView.text=s.toString;
}
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// This method is called to notify you that, within s, the count characters beginning at start are about to be replaced by new text with length after.
}
#Override
public void afterTextChanged(Editable s) {
// This method is called to notify you that, somewhere within s, the text has been changed.
}
});
The output is in a different screen (fragment/drawer)
You can do it using a combination of TextWatcher and LiveData.
Put a TextWatcher on your editText and store the data in a Livedata. (https://developer.android.com/topic/libraries/architecture/livedata)
Then observe this liveData and change the Textview accordingly.

How to know text lengh in EditView

How do i know the text lengh when i typing on the EditText.
this is my codes below.
I tried getting the lengh of EditText by using getText
but i connot control it to attch the other text.
EditText et = (EditText) findViewById(R.id.edit);
I uesd
OnKeyListener
in my code but It's not clear for me.
so I'm looking for other solution ~ to solve it.
What should i do for this?

If you don't want to use OnKeyListener, you can use TextWacher that is listener for EditText while you typing on the EditText.
If you typing on it even 1 letter, afterTextChanged will be called. so you can know how length it is by using s.getText.length().
et1.addTextChangedListener(new TextWatcher() {
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after)
}
#Override
public void afterTextChanged(Editable s) {
if(s.getText.length() > 5){
// do something you want
}
}
});

et.length() give you the length

Display warning when NumberPicker number exceed Max on Keyboard Entry

I have a Number Picker that allow user to enter some number within a fixed range.
By default the number will not allow the user to enter a number larger than the max set for the number picker.
However i would like to display a message when that happens. Is there a way to access the edittext in the number picker ? Thanks.

You can implement TextChangedListener that will register every change in the field so that you can act accordingly on it.
for example.
yourEditText = (EditText) findViewById(R.id.yourEditTextId);
yourEditText.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {
// you can call or do what you want with your EditText here
yourEditText. ...
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
public void onTextChanged(CharSequence s, int start, int before, int count) {}
});

Editext validation android

In Edittext Android :
How to implement this feature if user entered any valid numeric value it should get displayed in the form of decimal value.
e.g If user enters 4 then it should get displayed as 4.000 instead of only 4.
Also can be done using DONE button click handler of virtual keypad.

You can use like this
EditText et = (EditText)findViewById(R.id.myEditText);
et.addTextChangedListener(new TextWatcher(){
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start, int count, int after){}
public void onTextChanged(CharSequence s, int start, int before, int count){
//Check your et value and set it back.
// Retrieve 4.. set it to 4.000
}
});

Have you tried this on your XML?
android:inputType="numberDecimal"

Parse the string you are getting from editext to double or float in the click of a done button or wherever you want.

how to append text from edittext when the user inputs new texts in editext

I'm making a scrabble scorer app. And he user inputs the letter, in EditText, the score is computed and the word form and is displayed too...Now if another player is to add letters to the previous word the user should not reenter the letters in the word he just needs to add the letter from the previous word...say-- "inter" is previous word ... adding "n" should display "intern" adding again "ational" should display "international"....
Any help would be greatly appreciated...thankss a lot...

TextWatcher inputTextWatcher = new TextWatcher() {
public void afterTextChanged(Editable s) {
textview.setText(s.toString());
}
}
public void beforeTextChanged(CharSequence s, int start, int count, int after){
}
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
};
editText.addTextChangedListener(inputTextWatcher);
Try this one