抽取

package com.example.week3;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;

public abstract class BaseActivity extends AppCompatActivity {

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    setContentView(setView());

    initView();

    initdata();
}

protected abstract void initdata();

protected abstract void initView();

protected abstract int setView();

}

主页面

package com.example.week3;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;

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

public class MainActivity extends BaseActivity{
private ViewPager viewpager;
private RadioGroup group;
private RadioButton but1,but2,but3;
private Listlist;
@Override
protected void initdata() {

    list = new ArrayList<>();
    list.add(new Fragment1());
    list.add(new Fragment2());
    list.add(new Fragment3());

    //适配器
    viewpager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
        @Override
        public Fragment getItem(int i) {
            return list.get(i);
        }

        @Override
        public int getCount() {
            return list.size();
        }
    });

    //点击
    viewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {

        }

        @Override
        public void onPageSelected(int i) {
            switch (i) {
                case 0:
                    group.check(R.id.but1);
                    break;

                case 1:
                    group.check(R.id.but2);
                    break;

                case 2:
                    group.check(R.id.but3);
                    break;

            }
        }

        @Override
        public void onPageScrollStateChanged(int i) {

        }
    });
    //滑动
    group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId) {
                case R.id.but1:
                    viewpager.setCurrentItem(0);
                    break;

                case R.id.but2:
                    viewpager.setCurrentItem(1);
                    break;

                case R.id.but3:
                    viewpager.setCurrentItem(2);
                    break;

            }
        }
    });
}



@Override
//找控件
protected void initView() {
     viewpager=findViewById(R.id.viewpager);
     group=findViewById(R.id.group);
     but1=findViewById(R.id.but1);
     but2=findViewById(R.id.but2);
     but3=findViewById(R.id.but3);
}

@Override
//加载视图
protected int setView() {
    return R.layout.activity_main;
}

}