TextWatcher for more than one EditText

Question

I want to implement the TextWatcher interface for more than one EditText fields. Currently I am using :

text1.addTextChangedListener(this);
text2.addTextChangedListener(this);

then overriding the methods in my Activity:

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) 
{
 // do some operation on text of text1 field
 // do some operation on text of text2 field 
}

However this is working fine but I'm looking for other ways so that I can explicitly identify that in which EditText field the SoftKeyboard is currently focused.

Answer 1

I would do it like this:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    EditText e = new EditText(this);
    e.addTextChangedListener(new CustomTextWatcher(e));
}

private class CustomTextWatcher implements TextWatcher {
    private EditText mEditText;

    public CustomTextWatcher(EditText e) { 
        mEditText = e;
    }

    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }

    public void onTextChanged(CharSequence s, int start, int before, int count) {
    }

    public void afterTextChanged(Editable s) {
    }
}

Answer 2

I implemented it as:

edittext1.addTextChangedListener(this);
edittext2.addTextChangedListener(this);
edittext3.addTextChangedListener(this);

and:

@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

}

@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    if(edittext1.hasFocus()){
        //text changed for edittext1
    }else if(edittext2.hasFocus()){
        //text changed for edittext2
    }else {
        //text changed for edittext3
    }
}

@Override
public void afterTextChanged(Editable editable) {

}

Answer 3

Yes, you could use multiple instances of a custom TextWatcher that store the TextView. (TextView is actually the class that has addTextChangedListener.)

Similar to the hashCode solution above you can just check if getText()==s. Instead of either storing all your controls or findViewById multiple times, you could simply scan the content tree yourself once for the control that has the CharSequence.

public TextView findTextView(View v, CharSequence s)
{
   TextView tv;
   ViewGroup vg;
   int i, n;

   if (v instanceof TextView)
   {
      tv = (TextView) v;
      if (tv.getText()==s) return(tv);
   }

   else if (v instanceof ViewGroup)
   {
      vg = (ViewGroup) v;
      n = vg.getChildCount();
      for(i=0;i<n;i++)
      {
         tv = findTextView(vg.getChildAt(i), s);
         if (tv!=null) return(tv);
      }
   }

   return(null);
}

public void afterTextChanged(Editable s)
{
   TextView tv=findTextView(findViewById(android.R.id.content), s);
   if (tv==null) return;
   switch(tv.getId())
   {
      case R.id.path:
         break;
      case  R.id.title:
         break;
   }
}

Of course you could also use findTextView inside beforeTextChanged and onTextChanged.

Answer 4

using "CustomTextWatcher" idea, I done that

1) Crated a new TextWatcherListener interface:

public interface TextWatcherExtendedListener extends NoCopySpan
{
    public void afterTextChanged(View v, Editable s);

    public void onTextChanged(View v, CharSequence s, int start, int before, int count);

    public void beforeTextChanged(View v, CharSequence s, int start, int count, int after);
}

2)Created and used EditTextExtended instead of EditText (in my case):

public class EditTextExtended extends EditText
{
   private TextWatcherExtendedListener  mListeners = null;

   public EditTextExtended(Context context) 
   {
     super(context);
   }

   public EditTextExtended(Context context, AttributeSet attrs)
   {
      super(context, attrs);
   }

   public EditTextExtended(Context context, AttributeSet attrs, int defStyle)
   {
        super(context, attrs, defStyle);
   }

   public void addTextChangedListener(TextWatcherExtendedListener watcher) 
   {    
       if (mListeners == null) 
       {
           mListeners = watcher;
       }
   }

   public void removeTextChangedListener(TextWatcherExtendedListener watcher) 
   {
       if (mListeners != null) 
       {
           mListeners = null;        
       }
   }

   void  sendBeforeTextChanged(CharSequence text, int start, int before, int after)
   {
       if (mListeners != null) 
       {
           mListeners.beforeTextChanged(this, text, start, before, after);
       }
   }

   void  sendOnTextChanged(CharSequence text, int start, int before,int after) 
   {
       if (mListeners != null) 
       {
           mListeners.onTextChanged(this, text, start, before, after);
       }
   }

   void  sendAfterTextChanged(Editable text) 
   {
       if (mListeners != null)
       {
           mListeners.afterTextChanged(this, text);
       }
   }
}

3) So, where you need write this code:

myEditTextExtended.addTextChangedListener(this) //Let implement TextWatcherExtendedListener methods

4)use them:

@Override
public void onTextChanged(View v, CharSequence s, int start, int before, int count) 
{
   //Tested and works
   //do your stuff  
}


@Override
public void beforeTextChanged(View v, CharSequence s, int start, int count, int after)
{   
     //not yet tested but it should work    
}

@Override
public void afterTextChanged(View v, Editable s) 
{
    //not yet tested but it should work 
}

Well, let me know what do you think.

Answer 5

You can always define TextWatcher as a parameter to addTextChangedListener method.This way you can have multiple definitions for each edit text.

Answer 6

After try several ways to achieve this, i find the right way using EditText.isFocused() to distinguish one to another. For example:

    private class OnTextChangedListener implements TextWatcher {

    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void afterTextChanged(Editable editable) {
        if (edtName.isFocused()) {
            //do something
        } else if (edtEmail.isFocused()) {
            //do something
        } else if (edtContent.isFocused()) {
             //do something
        }
    }
}