SP实现引导页

package com.example.zuizhong;

import android.content.Intent;
import android.content.SharedPreferences;
import android.support.annotation.NonNull;
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 android.widget.RadioButton;
import android.widget.RadioGroup;

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

public class MainActivity extends AppCompatActivity {
private ViewPager pager;
private Button button;
private RadioGroup group;
private SharedPreferences sp;
private List list;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    pager = findViewById(R.id.yin_pager);
    button = findViewById(R.id.yin_btn);
    group = findViewById(R.id.radiogroup);
    list = new ArrayList<>();

    button.setVisibility(View.GONE);

    sp = getSharedPreferences(\"ding\",MODE_PRIVATE);
    if (sp.getBoolean(\"key\",false)) {
        Intent intent = new Intent(MainActivity.this,Zhuye.class);
        startActivity(intent);
    }

    sp.edit().putBoolean(\"key\",true).commit();

    int arr[] = {R.drawable.aa,R.drawable.bb,R.drawable.cc,R.drawable.dd,R.drawable.ee,R.drawable.ff};
    for (int i = 0; i < arr.length; i++) {
        ImageView view = new ImageView(MainActivity.this);
        view.setImageResource(arr[i]);
        list.add(view);
        RadioButton button = new RadioButton(MainActivity.this);
        group.addView(button);
    }
    group.check(group.getChildAt(0).getId());
    MyAdapter adapter = new MyAdapter();
    pager.setAdapter(adapter);
    pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {

        }

        @Override
        public void onPageSelected(int i) {
            group.check(group.getChildAt(i).getId());
            if (i == list.size()-1) {
                button.setVisibility(View.VISIBLE);
            }else {
                button.setVisibility(View.GONE);
            }
        }

        @Override
        public void onPageScrollStateChanged(int i) {

        }
    });
    button.set Listener(new View. Listener() {
        @Override
        public void  (View v) {
            Intent intent = new Intent(MainActivity.this,Zhuye.class);
            startActivity(intent);
            return;
        }
    });
}

private class MyAdapter extends PagerAdapter {
    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public boolean isViewFrom (@NonNull View arg0, @NonNull   arg1) {
        return arg0==arg1;
    }

    @NonNull
    @Override
    public   instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView view = list.get(position);
        container.addView(view);
        return view;
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull    ) {
        container.removeView((View)  );
    }

}

}