Question

在我的Android应用程序中。我有一个EditText和Textview.in Edittext用户需要输入金额。当他在编辑文本中输入金额时，在textview中它必须显示总价值（增加税额）。怎么做。

Answer 1

您可以使用textwatcher。

editText.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

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

    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});

Answer 2

您必须为EditText添加TextWatcher作为TextChangeListener：

    mEditText.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int start, int before, int count) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int start, int count, int after) {
             mTextView.setText(mEditText.getText().toString());
        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });

Answer 3

EditText Et = (EditText) findViewById(R.id.editTextID);
Et.addTextChangedListener(new TextWatcher() {
@Override
public void afterTextChanged(Editable s) {
    // TODO Auto-generated method stub
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    // TODO Auto-generated method stub
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    // TODO Auto-generated method stub
    // You need to write your code here when user need to enter the amount.
});

Answer 4

我添加了示例代码，它会持续观察edittext更改并执行一些操作，然后在textview中更新这些值。我希望这将有所帮助。 Plz遵循命名惯例。

EditText edit =（EditText）findViewById（R.id.editText1）;

    edit.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
            TextView twxt = (TextView) findViewById(R.id.textView1);
            Double sum = 0.00;
            Double userValue = 0.00;
            // TODO Auto-generated method stub
            try {
                userValue = Double.valueOf(s.toString());

            } catch (Exception e) {
                e.printStackTrace();
            }
            sum = 2 * (sum + userValue);
            twxt.setText(String.valueOf(sum));

        }

        @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

        }
    });

如何在Edittext中添加Change侦听器

4 个答案: