Question

我希望制作一个将一个单位转换为另一个单位的应用程序（比如货币）。所以它由2个编辑文本组成。一个用户输入值，另一个包含结果。现在，在这里，我没有使用“转换”按钮将值放在第二个编辑文本中，而是希望转换后的值出现在第二个编辑文本中，因为我输入的值是第一个。我怎样才能实现这一目标？感谢

Answer 1

为此使用TextWatcher。将其设置在用户输入的EditText上：

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) {             

        }

    });

修改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){              

    }

});

Android如何实时更改edittext的内容

1 个答案: