Question

如何强制在EditText中显示不能删除但单击Backspace的字母。恩。 [#____________] 在上面的示例中，＃是该edittext字段的默认值。使用Edittext.gettext（）时，它应该返回'＃32343'

Answer 1

立即想到几种方式，但我确实对你的问题感到困惑。看起来你想要（而不是显示一个空的EditText）显示一个带有开头字母的EditText。如果是这样的话，试试这个：

final EditText et = (EditText) findViewById(R.id.my_edit_text);

// default characters to display
// replace "#" with whatever you like
final String defaultTextDisplayed = "#";

// text is either set here or via xml, preferably via strings.xml
et.setText(defaultTextDisplayed);

et.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        // ignored
    }

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

    // This is the callback we're interested in. Any time
    // your user edits what is in the EditText, this method
    // is called. We'll use it listen for when a user tries
    // to delete the default display text.
    @Override
    public void afterTextChanged(Editable s) {
        // if the user attempts to delete and of the default
        // string displayed, just put it back
        if (s.length() < defaultTextDisplayed.length()) { 
            et.setText(defaultTextDisplayed);
        }
    }
});

Answer 2

您可以实施TextChangedListener，确保文本的某些部分不会被删除/覆盖。

试试此代码

final EditText edt = (EditText) findViewById(R.id.editText1);

edt.setText("#");
Selection.setSelection(edt.getText(), edt.getText().length());


edt.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            // 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 afterTextChanged(Editable s) {
            if(!s.toString().contains("#")){
                edt.setText("#");
                Selection.setSelection(edt.getText(), edt.getText().length());

            }

        }
    });

如何在Android中的EditText中设置Unchanged First Letter

2 个答案: