android - Adapter, Gallery, custom toast, inflate

package com.example.it.myapplication9_4;

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("갤러리 영화 포스터");

        Gallery gallery = (Gallery) findViewById(R.id.gallery1);

        MyGalleryAdapter galAdapter = new MyGalleryAdapter(this);
        gallery.setAdapter(galAdapter);
    }

    public class MyGalleryAdapter extends BaseAdapter {

        Context context;
        Integer[] posterID = {
                R.drawable.mov11, R.drawable.mov12, R.drawable.mov13, R.drawable.mov14, R.drawable.mov15,
                R.drawable.mov16, R.drawable.mov17, R.drawable.mov18, R.drawable.mov19, R.drawable.mov20 };

        String[] posterName = {
                "여인의 향기", "쥬라기공원", "포레스트검프", "그라운드호그데이", "혹성탈출",
                "아름다운비행", "내이름은 칸", "이제 모든 것이 끝난다", "마더", "킹콩을 들다" };


        public MyGalleryAdapter(Context context) {
            this.context = context;
        }

        @Override
        public int getCount() {
            return posterID.length;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView = new ImageView(context);
            imageView.setLayoutParams(new Gallery.LayoutParams(100, 150));
            imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
            imageView.setPadding(5,5,5,5);
            imageView.setImageResource(posterID[position]);

            final int pos = position;
            imageView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    ImageView ivPoster = (ImageView) findViewById(R.id.ivPoster);
                    ivPoster.setScaleType(ImageView.ScaleType.FIT_CENTER);
                    ivPoster.setImageResource(posterID[pos]);

                    LayoutInflater inflater = getLayoutInflater();
                    View toastView = inflater.inflate(R.layout.toast, (ViewGroup) findViewById(R.id.toast_layout_root));

                    TextView txtView1 = (TextView) toastView.findViewById(R.id.txtView1);
                    txtView1.setText(posterName[pos]);

                    Toast toast = new Toast(getApplicationContext());
                    toast.setDuration(Toast.LENGTH_SHORT);
                    toast.setView(toastView);
                    toast.show();
                }
            });

            return imageView;
        }
    }


}

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

    <Gallery
        android:id="@+id/gallery1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:spacing="5dp"></Gallery>

    <ImageView
        android:id="@+id/ivPoster"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="20dp" />

</LinearLayout>

<?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:gravity="center"
    android:id="@+id/toast_layout_root">

    <ImageView
        android:id="@+id/s"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/txtView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="영화제목"
        android:textSize="30dp"
        android:textStyle="bold"
        android:textColor="#ff0000"
        android:gravity="center_vertical" />
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

</LinearLayout>