안드로이드 - 버튼, 새로운 창에 새로운 버튼 클릭

자바

package com.example.ryan.myapplication;

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

public class MainActivity extends AppCompatActivity {

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


    //login method
    public void onButtonClicked(View view){
        final Dialog loginDialog = new Dialog(this);
        loginDialog.setContentView(R.layout.second);
        loginDialog.setTitle("로그인화면");

        Button login = (Button)loginDialog.findViewById(R.id.login);
        Button cancel = (Button)loginDialog.findViewById(R.id.cancel);

        final EditText username =(EditText)loginDialog.findViewById(R.id.username);
        final EditText password = (EditText)loginDialog.findViewById(R.id.password);

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(username.getText().toString().trim().length()>0&&password.getText().toString().trim().length()>0){
                    Toast.makeText(getApplicationContext(),"로그인성공",Toast.LENGTH_SHORT).show();
                loginDialog.dismiss();
                }
                else {
                    Toast.makeText(getApplicationContext(),"다시입력하세요",Toast.LENGTH_SHORT).show();
                }
            }
        });

        cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                loginDialog.dismiss();
            }
        });
        loginDialog.show();



    }






}

xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.ryan.myapplication.MainActivity">

    <Button
        android:id="@+id/button3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="onButtonClicked"
        android:text="login" />
</LinearLayout>

xml2

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#fff"
    android:orientation="vertical">

    <EditText
        android:id="@+id/username"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="username"
        android:inputType="textPersonName" />

    <EditText
        android:id="@+id/password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="password"
        android:inputType="textPersonName" />

    <Button
        android:id="@+id/login"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="login" />

    <Button
        android:id="@+id/cancel"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@android:string/cancel" />
</LinearLayout>