ViewPager复用

ViewPager复用代码很简单 记录一下 主要是用 LinkedList 在 destroyItem 中添加移除的 View 在 instantiateI 中复用移除的 View import android support v4 view PagerAdapter import android support v4 view ViewPager import android support v7 app

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);
}

});

}

}

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