判断IP地址是否正确

String ip = new StringBuilder()
                            .append(et_1.getText().toString().trim())

                            .append(et_2.getText().toString().trim())

                            .append(et_3.getText().toString().trim())

                            .append(et_4.getText().toString().trim()).toString();

String strregular =
 "(([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.))";

package com.example.ipdemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {
    private EditText et_1;
    private EditText et_2;
    private EditText et_3;
    private EditText et_4;
    private Button sure;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_1=findViewById(R.id.et_1);
        et_2= findViewById(R.id.et_2);
        et_3=findViewById(R.id.et_3);
        et_4=findViewById(R.id.et_4);
        sure=findViewById(R.id.sure);
        sure.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                    String ip = new StringBuilder()
                            .append(et_1.getText().toString().trim())

                            .append(et_2.getText().toString().trim())

                            .append(et_3.getText().toString().trim())

                            .append(et_4.getText().toString().trim()).toString();

String strregular =
 "(([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.)(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5]\\.))";

                    boolean matches = ip.matches(strregular);

                    if (matches) {

                        Toast.makeText(MainActivity.this, "ip设置成功", Toast.LENGTH_SHORT).show();

                    } else {

                        Toast.makeText(MainActivity.this, "ip设置失败", Toast.LENGTH_SHORT).show();

                    }
                }

            });
    }
}