Edittext validation in Android Studio

Question

Hello hope that you are fine would like to get an help on how i can validate the Edittetxt make sure that the phone number entered is correct and the password should also match before i submit the data i have seen couple of examples but i didn't get the actual concept on how the whole thing works.

    <android.support.v7.widget.CardView
            android:id="@+id/card_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="10dp"
            android:paddingTop="16dp"
            android:layout_gravity="center">
            <TextView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/penta_ujumbe"
                android:text="@string/penta_join"
                android:textSize="16sp"
                android:layout_marginTop="16dp"/>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="@android:color/darker_gray"
                android:layout_marginTop="90dp" />

            <EditText
                android:layout_width="270dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="130dp"
                android:layout_gravity="center_horizontal"
                android:id="@+id/penta_jina"
                android:hint="Jina lako"
                />
            <EditText
                android:layout_width="270dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="180dp"
                android:layout_gravity="center_horizontal"
                android:id="@+id/penta_simu"
                android:hint="Namba Ya Simu"
                android:digits="1,2,3,4,5,6,7,8,9,0,+"
                />

            <EditText
                android:layout_width="270dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="230dp"
                android:layout_gravity="center_horizontal"
                android:id="@+id/penta_siri"
                android:hint="NenoSiri"
                />
            <EditText
                android:layout_width="270dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="280dp"
                android:layout_gravity="center_horizontal"
                android:id="@+id/penta_nsiri"
                android:hint="Rudia Nenosiri"
                />
            <Button
                android:layout_width="260dp"
                android:layout_height="wrap_content"
                android:background="@color/colorPrimary"
                android:id="@+id/penta_fungua"
                android:layout_below="@+id/pik_siri"
                android:layout_marginTop="330dp"
                android:layout_gravity="center_horizontal"
                android:text="Fungua akaunti"
                android:textAllCaps="false"
                android:textSize="20sp"
                android:textColor="@color/colorWhite"
                />
        </android.support.v7.widget.CardView>
    </RelativeLayout>
</ScrollView>

The codes in the Activity are as follows the problem is that the application crashes a lot.

    private boolean validate(){
    boolean valid = true;
    String mjina  =  pikujina.getText().toString();
    String mnamba =  pikunamba.getText().toString();
    String msiri  =  pikusiri.getText().toString();
    String mnsiri =  pikunsiri.getText().toString();

    if (mjina.isEmpty() || mjina.length() < 3) {
        pikujina.setError("at least 3 characters");
        valid = false;
        return valid;
    }
    if (mnamba.isEmpty() || !isPhoneNumberValid(mnamba)) {
        pikunamba.setError("enter a valid phone number with your country         code");
        valid = false;
        return valid;
    }
    if (msiri.isEmpty() || msiri.length() < 4 || msiri.length() > 10) {
        pikunsiri.setError("between 4 and 10 alphanumeric characters");
        valid = false;
        return valid;
    }
    if (mnsiri.isEmpty() || mnsiri.length() < 4 || mnsiri.length() > 10) {
        pikunsiri.setError("between 4 and 10 alphanumeric characters");
        valid = false;
        return valid;
    }
    if (!msiri.equals(mnsiri)){
        pikunsiri.setError("Password do not Match");
        pikunsiri.setError("Password do not Match");
        valid = false;
        return valid;
    }
    else {
        return valid;
    }


}


public static boolean isPhoneNumberValid(String phoneNumber) {

    boolean valid = true;
    String regex = "^(?:00255|\\+255|0)[6-9][0-9]{9}";

    if (!phoneNumber.matches(regex)) {
        valid = false;
    }
    return valid;
}

AND I CALL THIS FUNCTION USING AN IF CONDITION INSIDE THE ONCLICK FUNCTION.

        public void onClick(View v) {
        if(validate()){
            Toast.makeText(piku_join.this,"Entered"+pikunamba+"and password entered is",Toast.LENGTH_SHORT).show();
        }else {
            Toast.makeText(piku_join.this,"Failed"+pikunamba+"and password entered is",Toast.LENGTH_SHORT).show();

        }

Answer 1

here i mentioned some edittext validation check it out, I hope it will help u:

private boolean validate() {
    boolean valid = true;

    String name = et_username.getText().toString();
    String email = et_email.getText().toString();
    String phone = et_phone.getText().toString();
    String password = et_password.getText().toString();

    if (name.isEmpty() || name.length() < 3) {
        et_username.setError("at least 3 characters");
        valid = false;
    } else {
        et_username.setError(null);
    }

    if (email.isEmpty() || !android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
        et_email.setError("enter a valid email address");
        valid = false;
    } else {
        et_email.setError(null);
    }
    if (phone.isEmpty() || !isPhoneNumberValid(phone)) {
        et_phone.setError("enter a valid phone number with your country code");
        valid = false;
    } else {
        et_phone.setError(null);
    }

    if (password.isEmpty() || password.length() < 4 || password.length() > 10) {
        et_password.setError("between 4 and 10 alphanumeric characters");
        valid = false;
    } else {
        et_password.setError(null);
    }

    return valid;
}

public static boolean isPhoneNumberValid(String phoneNumber) {

    boolean valid = true;
    String regex = "^(?:0091|\\+91|0)[7-9][0-9]{9}";

    if (!phoneNumber.matches(regex)) {
        valid = false;
    }
    return valid;
}