Android如何实时更改edittext的内容[重复]

Question

我正在寻找将一个单位转换为另一个单位（比如货币）的应用程序。所以它由2个编辑文本组成。一种是用户输入值，另一种是包含结果。现在，在这里，我希望在第一个编辑文本中输入值时，转换后的值出现在第二个编辑文本中，而不是使用“转换”按钮将值放入第二个编辑文本中。我怎样才能做到这一点？ 谢谢

Answer 1

为此使用TextWatcher。在用户输入的EditText 上设置：

myEditText1.addTextChangedListener(new TextWatcher() {

        @Override
        public void afterTextChanged(Editable s) {
                        String value = s.toString();

                        // Perform computations using this string
                        // For example: parse the value to an Integer and use this value

                        // Set the computed value to the other EditText
                        myEditText2.setText(computedValue);
        }

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

        }

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

        }

    });

编辑 1：

检查空字符串"":

myEditText1.addTextChangedListener(new TextWatcher() {

    @Override
    public void afterTextChanged(Editable s) {
        String value = s.toString();

        if (value.equals("")) {
            myEditText1.setText("0");

            // You may not need this line, because "myEditText1.setText("0")" will
            // trigger this method again and go to else block, where, if your code is set up
            // correctly, myEditText2 will get the value 0. So, try without the next line
            // and if it doesn't work, put it back.
            myEditText2.setText("0");
        } else {

            // Perform computations using this string
            // For example: parse the value to an Integer and use this value

            // Set the computed value to the other EditText
            myEditText2.setText(computedValue);
        }
}

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

    }

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

    }

});