首次安装+viewpager

import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;

import com.example.admin.lianxi04.adapter.MyAdapter1;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.squareup.picasso.Picasso;

import java.util.ArrayList;
import java.util.List;

public class StartActivity extends AppCompatActivity {
    private SharedPreferences info;
    private ViewPager view_pager;
    private List<Integer> list;
    private Button btn_start;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_start);
        view_pager= findViewById(R.id.view_pager);
        btn_start=findViewById(R.id.btn_start);
        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(StartActivity.this,MainActivity.class));
                finish();
            }
        });
        list=new ArrayList<>();
        list.add(R.drawable.a);
        list.add(R.drawable.b);
        list.add(R.drawable.c);

        info = getSharedPreferences("info", MODE_PRIVATE);
        boolean is_login = info.getBoolean("is_login", true);
        if (is_login){
            MyAdapter1 myAdapter1 = new MyAdapter1(list, StartActivity.this);
            view_pager.setAdapter(myAdapter1);
            view_pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                @Override
                public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

                }

                @Override
                public void onPageSelected(int position) {
                    int i = view_pager.getCurrentItem();
                    if (i==list.size()-1){
                        btn_start.setVisibility(View.VISIBLE);
                    }else {
                        btn_start.setVisibility(View.GONE);
                    }
                }

                @Override
                public void onPageScrollStateChanged(int state) {

                }
            });
        }else {
            startActivity(new Intent(StartActivity.this,MainActivity.class));
            finish();
        }
    }

}