Question

我有一个编辑Text.I不希望第一个字母是空格。如果用户点击空格，则第一个字母光标不应移动。

Answer 1

像这样创建一个TextWatcher

public class MyTextWatcher implements TextWatcher {
    private EditText editText;

    public MyTextWatcher(EditText editText) {
        this.editText = editText;
    }

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

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        String text = editText.getText().toString();
        if (text.startsWith(" ")) {
            editText.setText(text.trim());
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
}

并将其添加到EditText

editText.addTextChangedListener(new MyTextWatcher(editText));

Answer 2

基于卢卡的第一个答案：

TextWatcher mWatcher = new TextWatcher() { 
@Override public void afterTextChanged(Editable editable) {
 if (myEditText.getText().toString().startsWith(" ")) 
myEditText.setText(""); 
}

我将equals更改为startsWith 比设定

Answer 3

    var myApp = angular.module('myApp', []);

    myApp.controller('mainCtrl', function($scope){

        $scope.countryList = [
            {
                id: null,
                name: 'Please Select',
                states: [
                    {name: 'Please Select', stateid: null}
                ]
            },
            {
              id: 1,
              name: 'United States of America',
              states: [
              {name: 'Alabama', stateid: 1},
              {name: 'Alaska', stateid: 2},
              {name: 'Arizona', stateid: 3}
              ]
            },
            {
              id: 2,
              name: 'Australia',
              states: [
              {name: 'Australian Capital Territory', stateid: 1},
              {name: 'New South Wales', stateid: 2},
              {name: 'Northern Territory', stateid: 3}
              ]
            },
        ];

        $scope.stateList = $scope.countryList[0].states;
    })

然后

TextWatcher myWatcher = new TextWatcher() {
 @Override
        public void afterTextChanged(Editable s) {
            if (myEditText.getText().toString().equals(" "))
              myEditText.setText("");
        }

Answer 4

您可以按照以下方法将InputFilter设置为Edittext。它会限制用户在开始时输入空间。

 InputFilter filter = new InputFilter() {
        public CharSequence filter(CharSequence source, int start, int end,
                                   Spanned dest, int dstart, int dend) {
            if (source.length()>0 &&Character.isWhitespace(source.charAt(0)) && yourEditText.getText().toString().length()==0) {
                return "";
            }
            return source;
        }
    };
yourEditText.setFilters(new InputFilter[] { filter });

与此方案中的InputFilter相比，
TextWatcher在性能方面更可靠。您可以参考https://stackoverflow.com/a/33855940/3817374获取更详细的信息。

Answer 5

添加if else条件以检查第一个字母

if(EditText.getText().charAt(0)!=" "){
//COOL!
}
else
{
//ERROR!
}

确保它在ui线程上运行

如何强制editText不要以空格开头

5 个答案: