How to check if an EditText was changed or not?

问题:

I need to know if an EditText was changed or not, not whether or not the user inputted some text in the field, but only the if String was changed.

回答1:

You need a TextWatcher

See it here in action:

EditText text = (EditText) findViewById(R.id.YOUR_ID);
text.addTextChangedListener(textWatcher);


private TextWatcher textWatcher = 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) {

  }
}

回答2:

If you change your mind to listen to the keystrokes you can use OnKeyListener

    EditText et = (EditText) findViewById(R.id.search_box); 

    et.setOnKeyListener(new View.OnKeyListener() {

        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            //key listening stuff
            return false;
        }
    });

But Johe's answer is what you need.

回答3:

Implement a TextWatcher. It gives you three methods, beforeTextChanged, onTextChanged, and afterTextChanged. The last method shouldn't be called until something changes anyway, so that's a good thing to use for it.

回答4:

This actually worked for me

EditText text = (EditText) findViewById(R.id.YOUR_ID);

text.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

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

        if(your_string.equals(String.valueOf(s))) {
           //do something
        }else{
            //do something 
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});