android - 如何在 android 上捕获 KeyEvents？

Question

我需要在 EditText 上监听事件

1. 当用户开始输入时
2. 当失去焦点时

我试过了，还是不行。我做错了什么？

etTo.setOnKeyListener(new OnKeyListener(){

    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if(event.getAction() ==KeyEvent.ACTION_DOWN){
            etTo.setText("");
        }
    return false;
    }           
});

Answer 1

对于第一个你可以试试这个:

   myEditText.addTextChangedListener(new TextWatcher() {
 public void afterTextChanged(Editable s) {
   //do something
}

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

public void onTextChanged(CharSequence s, int start, int before, int count) { 
   //do something
}
});

第二个试试这个:

     myEditText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        if (actionId == EditorInfo.IME_ACTION_DONE) {

            yourcalc();

            return true;
        }
        return false;
    }
});