EditText文本改變事件

edittext = (EditText) findViewById(R.id.edittext);
        edittext.addTextChangedListener(new TextWatcher() {
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }
//            文本改變
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                Toast.makeText(MainActivity.this,"1"+edittext.getText().toString()+"s="+s+"-start"+start+"-before"+before+",count"+count,0).show();
            }
//            後文變
            public void afterTextChanged(Editable s) {
                Toast.makeText(MainActivity.this,"2"+edittext.getText().toString(),Toast.LENGTH_LONG).show();
            }
        });