在android中，如何在向服务器发送请求之前进行验证检查？

我有一个包含手机号码、通行证和电子邮件的应用程序，场景是这样的，如果用户输入类似“lll”的电子邮件id并按下提交按钮，则应用程序将向服务器发送类似“lll”的值，但我想要的条件只有在用户在电子邮件编辑文本中输入某些内容时才会检查，若用户并没有输入任何东西，那个么应用程序应该只使用手机和密码向服务器发送请求，因为电子邮件是可选的。我怎么做

代码：-

@Override
                    public void onClick(View v) {
                        m_Email = m_EmailEditText.getText().toString().trim();
                        if (!isValidEmail(m_Email)) {
                            CSnackBar.getInstance().showSnackBarError(findViewById(R.id.mainLayout), "Please enter valid Email Id", getApplicationContext());

                        } else {
                            confirmationDialog();//open confirmation dialog.....
                        }

                    }
                });
    /*validation for email*/
private boolean isValidEmail(String email) {// validation for email Id
    String emailPattern = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
            + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";

    Pattern pattern = Pattern.compile(emailPattern);
    Matcher matcher = pattern.matcher(email);
    return matcher.matches();
}

---

您可以检查电子邮件是否为空。
如果电子邮件不为空->验证电子邮件
如果电子邮件为空->什么也不做

public void onClick(View v) {
        m_Email = m_EmailEditText.getText().toString().trim();
        if (!TextUtils.isEmpty(m_Email)) { // check m_Email is not empty
            // m_Email is not empty
            if (!isValidEmail(m_Email)) {
                CSnackBar.getInstance().showSnackBarError(findViewById(R.id.mainLayout), "Please enter valid Email Id", getApplicationContext());
            } else {
                confirmationDialog(); //open confirmation dialog.....
            }
        }
        ...
}

我就是这么做的

if (email.contains("@") ){
    if ( email.charAt(email.length-3)=='.' || email.charAt(email.length-4) == '.'){
    //do stuff
    }}
    else Toast.makeText(this , "Email is not valid" , Toast.LENGTH_SHORT).show;

这确保了电子邮件就像something@something.xxx或.xx 因为有太多的领域，我认为有2或3个字符在它

---

您可以进行相应的编辑，但它可以工作

使用此功能检查邮件是否符合格式：

public final static boolean isValidEmail(CharSequence target) {
        if (target == null) {
            return false;
        } else {
            return android.util.Patterns.EMAIL_ADDRESS.matcher(target).matches();
        }
    }

然后用你的方法

p、 在这里，我使用默认的匹配器作为电子邮件地址。所以没有 需要创建我们自己的匹配器

---

我曾经遇到过类似的问题，我已经准备了一个模块来检查它。 我已经为所有类型的检查准备了代码，比如姓名、电话号码、电子邮件ID、注册号等

这是Validation.java类，我们在其中定义了所有类型的检查：-

package com.Validation;
import android.util.Log;
import android.widget.EditText;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Validation {

    // Regular Expression
    // you can change the expression based on your need
    private static final String EMAIL_REGEX = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";
    private static final String PHONE_REGEX = "\\d{3}-\\d{7}";
    public static final String USERNAME_PATTERN =  "^[a-z0-9_-]{3,15}$";

    private static Matcher matcher;
    private static Pattern pattern;
   /// private static final String USERNAME_PATTERN =;
    // Error Messages
    private static final String REQUIRED_MSG = "required";
    private static final String EMAIL_MSG = "invalid email";
    private static final String PHONE_MSG = "###-#######";
////for user name validation

    public Validation(){

        pattern = Pattern.compile(Validation.USERNAME_PATTERN);
    }

    public static boolean validateusername(String username){

        matcher = pattern.matcher(username);
        return matcher.matches();

    }

    // call this method when you need to check email validation
    public static boolean isEmailAddress(EditText editText, boolean required) {
        return isValid(editText, EMAIL_REGEX, EMAIL_MSG, required);
    }

    // call this method when you need to check phone number validation
    public static boolean isPhoneNumber(EditText editText, boolean required) {


        return isValid(editText, PHONE_REGEX, PHONE_MSG, required);
    }

    // return true if the input field is valid, based on the parameter passed
    public static boolean isValid(EditText editText, String regex, String errMsg, boolean required) {

        String text = editText.getText().toString().trim();



        editText.setError(null);

        // text required and editText is blank, so return false
        if ( required && !hasText(editText) ) return false;

        // pattern doesn't match so returning false
        if (required && !Pattern.matches(regex, text)) {

            editText.setError(errMsg);
            return false;
        };

        return true;
    }

    // check the input field has any text or not
    // return true if it contains text otherwise false
    public static boolean hasText(EditText editText) {

        String text = editText.getText().toString().trim();
        editText.setError(null);

        // length 0 means there is no text
        if (text.length() == 0) {
            editText.setError(REQUIRED_MSG);
            return false;
        }

        return true;
    }
}

现在，在您要进行验证的活动中，请输入如下代码：-

public class MyActivity extends Activity {

    private EditText etNormalText;
     private EditText etEmailAddrss;
    private EditText etPhoneNumber;
    private Button btnSubmit;
    public static final String USERNAME_PATTERN =  "^[a-z_-]{1,15}$";
    public static final String ENUM_PATTERN =  "^[a-z0-9_-]{3,12}$";

    private static Matcher matcher;
    private static Pattern pattern,patforeno;


    public MyActivity(){

        pattern = Pattern.compile(USERNAME_PATTERN);
        patforeno = Pattern.compile(ENUM_PATTERN);

    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        registerViews();
    }

    public static boolean validateusername(String username){

        matcher = pattern.matcher(username);
        return matcher.matches();

    }
    private void registerViews() {
        etNormalText = (EditText) findViewById(R.id.et_normal_text);
        // TextWatcher would let us check validation error on the fly
        etNormalText.addTextChangedListener(new TextWatcher() {
            public void afterTextChanged(Editable s) {
                //Validation.hasText(etNormalText);


            }
            public void beforeTextChanged(CharSequence s, int start, int count, int after){}
            public void onTextChanged(CharSequence s, int start, int before, int count){}
        });

        etEmailAddrss = (EditText) findViewById(R.id.et_email_address);
        etEmailAddrss.addTextChangedListener(new TextWatcher() {
            // after every change has been made to this editText, we would like to check validity
            public void afterTextChanged(Editable s) {
                Validation.isEmailAddress(etEmailAddrss, true);
            }
            public void beforeTextChanged(CharSequence s, int start, int count, int after){}
            public void onTextChanged(CharSequence s, int start, int before, int count){}
        });

        etPhoneNumber = (EditText) findViewById(R.id.et_phone_number);
        etPhoneNumber.addTextChangedListener(new TextWatcher() {
            public void afterTextChanged(Editable s) {


                    Validation.isPhoneNumber(etPhoneNumber, false);

            }
            public void beforeTextChanged(CharSequence s, int start, int count, int after){}
            public void onTextChanged(CharSequence s, int start, int before, int count){}
        });

        btnSubmit = (Button) findViewById(R.id.btn_submit);
        btnSubmit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                /*
                Validation class will check the error and display the error on respective fields
                but it won't resist the form submission, so we need to check again before submit
                 */
                if (checkValidation())
                    submitForm();
                else
                    Toast.makeText(MyActivity.this, "Form contains error", Toast.LENGTH_LONG).show();
            }
        });
    }

    private void submitForm() {
        // Submit your form here. your form is valid
        etNormalText = (EditText) findViewById(R.id.et_normal_text);
        boolean isvalidu = false;
        etPhoneNumber = (EditText) findViewById(R.id.et_phone_number);
        etEmailAddrss = (EditText) findViewById(R.id.et_email_address);
        ////email validation


        if (Validation.isEmailAddress(etEmailAddrss, true)) {

            Log.d("mail", "validmail");

        } else {
            Log.d("mail", "invalidvalidmail");
        }

        ///phone number validation
        int length = etPhoneNumber.getText().toString().length();
        Log.d("length", String.valueOf(length));
        int ten = 10;
        if (length != ten) {
Toast.makeText(getApplicationContext(),"Please enter your ten digit mobile number",Toast.LENGTH_LONG).show();
        } else {
            Validation.isPhoneNumber(etPhoneNumber, false);
            Log.d("numberpho","valid");
        }
        ///username validation
        try {
          isvalidu=validateusername(etNormalText.getText().toString());
            Log.d("hello valid username", "error message"+isvalidu);
            Toast.makeText(this, "Submitting form..."+isvalidu, Toast.LENGTH_LONG).show();

        } catch (Exception e) {
            Log.d("hello valid username", "error message"+isvalidu);
            Toast.makeText(this, "Submitting form...", Toast.LENGTH_LONG).show();
        }
    }

    private boolean checkValidation() {
        boolean ret = true;

        if (!Validation.hasText(etNormalText)) ret = false;
        if (!Validation.isEmailAddress(etEmailAddrss, true)) ret = false;
        if (!Validation.isPhoneNumber(etPhoneNumber, false)) ret = false;

        return ret;
    }
}

---

因此，希望这些对您的代码有所帮助，实际上您必须根据您的需求优化我的代码。registerView（）和checkValidation（）以及submitforms（）验证方法非常重要。

我只想检查验证，如果输入了电子邮件，如果没有输入电子邮件，则无需检查确定，然后只使用Textutil.isempti我只想检查密码，当用户在电子邮件id中输入某物时，编辑文本如果没有输入任何内容，则无需检查密码请检查此链接并使用Saripar