Android studio click button to jump to new Activity

package com.example.admin.onclick;

import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;


public class MainActivity extends AppCompatActivity  {
    private EditText et_phone;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        et_phone = (EditText) findViewById(R.id.et_phone);
        Button bt_call = (Button) findViewById(R.id.bt_call);
   

        //设点事件第一种
        bt_call.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
         
             //在按钮响应//MainActivity.this 为当前窗体，LoginActivity.class 为跳到的第二个窗体
                Intent intent =new Intent(MainActivity.this,LoginActivity.class);
                startActivity(intent);

            }
        });

    }