Android EditText 監聽輸入

需求是輸入點額才出現確定按鈕，因此要監聽EditText的輸入。而EditText的監聽輸入是：

priceReplyE.addTextChangedListener(new TextWatcher() {
			
			@Override
			public void onTextChanged(CharSequence s, int start, int before, int count) {
				yesBtn.setVisibility(Button.VISIBLE);
				
			}
			
			@Override
			public void beforeTextChanged(CharSequence s, int start, int count,
					int after) {
				// TODO Auto-generated method stub
				
			}
			
			@Override
			public void afterTextChanged(Editable s) {
				// TODO Auto-generated method stub
				
			}
		});
	}