ViewPager复用

编程汇总 • 2025-03-10 18:01 • 阅读 8
代码很简单，记录一下
主要是用LinkedList在destroyItem中添加移除的View，在instantiateItem中复用移除的View。
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.TextView;



import java.util.ArrayList;

import java.util.LinkedList;

import java.util.List;



public class MainActivity extends AppCompatActivity { 

   



    private PagerAdapter mPagerAdapter;

    private List mDataList = new ArrayList<>();

    private Button mUpdate, mDelete, mAdd, mClean;

    private LinkedList mViewCache = new LinkedList<>();

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        mDataList.add("1");

        mDataList.add("2");

        mDataList.add("3");

        mDataList.add("4");

        mDataList.add("5");



        ViewPager viewPager = findViewById(R.id.viewPager);

        viewPager.setAdapter(mPagerAdapter = new PagerAdapter() {

            @Override

            public int getCount() {

                return mDataList.size();

            }



            @Override

            public boolean isViewFromObject(View view, Object object) {

                return view == object;

            }





            @Override

            public Object instantiateItem(ViewGroup container, int position) {

                View view = mViewCache.size() > 0 ? mViewCache.removeFirst() : null;

                String str = "";

                if (view == null) {

                    view = View.inflate(MainActivity.this, R.layout.item_pager, null);

                    str = "";

                } else{

                    str = "复用了position为= " + view.getTag() + " 的Item";

                }

                TextView textView = view.findViewById(R.id.pager_tv);

                textView.setText(str + "\n" +mDataList.get(position));

                view.setTag(position);

                container.addView(view);

                return view;

            }



            @Override

            public void destroyItem(ViewGroup container, int position, Object object) {

                View deleteView = (View) object;

                container.removeView(deleteView);

                mViewCache.add(deleteView);

            }



        });



    }



}
ViewPager复用

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