android - 如何在 EditText 中执行验证

Question

我必须EditBox检查用户输入的号码是否正确。为此，我想调用这样一个事件，该事件允许用户在EditBox数字正确时输入数字，否则，如果数字不正确，则不允许用户输入EditBox. 怎么做？任何例子都会对我有所帮助。

Answer 1

在其 beforeTextChangedMethod() 中使用onTextChangedListener()和验证 .. 像这样的东西..

 ((EditText)findViewById(R.id.et_testo)).addTextChangedListener(new TextWatcher() {

    public void afterTextChanged(Editable s) {
        ((TextView)findViewById(R.id.numcaratteri)).setText(String.format(getString(R.string.caratteri), s.length()));

    }

    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {
        // Validate here

    }

    public void onTextChanged(CharSequence s, int start, int before,
            int count) {
        // TODO Auto-generated method stub

    }

});

Answer 2

final Pattern pattern = Pattern.compile("[0-9]");
editText.addTextChangedListener(new TextWatcher() {

    public void afterTextChanged(Editable s) {
        // TODO Auto-generated method stub
        Matcher matcher = pattern.matcher(s);
        if (matcher.find())
        {
            s.replace(0, s.length(), s.toString().replaceAll("[0-9]", ""));
        }
    }

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

    public void onTextChanged(CharSequence s, int start, int before,
            int count) {
        // TODO Auto-generated method stub
    }

});

Answer 3

您将不得不使用TextWatcher。

你可以去这里。这里也给出了例子，你可以参考一下。

Answer 4

您可以使用 2 种方式
1. textwatcher
2. Inputfilter
我附上了包含两者的代码

public class MainActivity extends Activity {   
EditText editTxt;  
private TextView regresult;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); 
    editTxt =(EditText)findViewById(R.id.editID);
    regresult = (TextView)findViewById(R.id.txtID);
    String urName=editTxt.getText().toString();

    editTxt.setFilters(new InputFilter[]{new DecimalDigitsInputFilter()});      
    editTxt.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {    
        }           
        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
        }           
        @Override
        public void afterTextChanged(Editable s) {
              if (editTxt.getText().toString().matches("(^([0-9]{0,3})?)(\\.[0-9]{0,1})?$"))
                {
                    regresult.setText("");
                }
                else
                {
                    regresult.setText("invalid number");
                }
        }
    });
}}  


class DecimalDigitsInputFilter implements InputFilter
{   
Pattern mPattern;

public DecimalDigitsInputFilter()
{
    mPattern = Pattern.compile("(^([0-9]{0,2})?)(\\.[0-9]{0,1})?$"); //here u can give your required pattern
}
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
    // TODO Auto-generated method stub
     Matcher matcher = mPattern.matcher(dest);
        if(!matcher.matches())
        {
            return "";
        }
        return null;
}}