Android实现ViewPager无限循环效果（二）

本文实例为大家分享了Android实现ViewPager无限循环效果的第二种方式，供大家参考，具体内容如下

原理：在Adapter中将getCount设置为无限大

package com.xiaomai.myproject.demo;

import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.xiaomai.myproject.R;
import com.xiaomai.myproject.adapter.LoopViewPagerAdapter2;
import com.xiaomai.myproject.base.baseActivity;

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


public class LoopViewPagerDemo2Activity extends baseActivity {

  
  private static final int UPDATe_TIME = 3 * 1000;

  private ViewPager mViewPager;

  private LoopViewPagerAdapter2 mAdapter;

  
  private LinearLayout mLinearLayoutPonits;

  
  private int[] mImageIds;

  
  private List mImageList;

  
  private int mCurrentPageIndex;

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

  }

  @Override
  protected void initVariables() {
    super.initVariables();
    
    mImageIds = new int[]{
 R.mipmap.ic_launcher,
 R.mipmap.ic_launcher,
 R.mipmap.ic_launcher,
 R.mipmap.ic_launcher,
 R.drawable.my_toast,
 R.drawable.my_toast,
 R.drawable.my_toast,
 R.drawable.my_toast};
    
    mImageList = new ArrayList<>();
    //额外添加两张图片
    ViewGroup.LayoutParams layoutParams =
 new ViewGroup.LayoutParams(
     ViewGroup.LayoutParams.MATCH_PARENT,
     ViewGroup.LayoutParams.WRAP_CONTENT);
    for (int i = 0; i < mImageIds.length; i++) {
      ImageView imageView = new ImageView(mContext);
      imageView.setLayoutParams(layoutParams);
      mImageList.add(imageView);
    }
  }

  @Override
  protected void initViews() {
    mLinearLayoutPonits = (LinearLayout) findViewById(R.id.activity_ll_container);
    mViewPager = (ViewPager) findViewById(R.id.activity_loop_viewpager);
    mAdapter = new LoopViewPagerAdapter2(mImageList, mImageIds);
    mViewPager.setAdapter(mAdapter);
    int middle = mAdapter.getCount() / 2;
    mViewPager.setCurrentItem(middle - middle % mImageList.size());
  }

  @Override
  protected int getContentLayout() {
    return R.layout.act_loopviewpager;
  }
}

代码：

package com.xiaomai.myproject.adapter;

import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import java.util.List;


public class LoopViewPagerAdapter2 extends PagerAdapter {

  private List mImageList;

  private int[] mImageIds;

  public LoopViewPagerAdapter2(List mImageList, int[] mImageIds) {
    this.mImageList = mImageList;
    this.mImageIds = mImageIds;
  }

  @Override
  public int getCount() {
    return Integer.MAX_VALUE;
  }

  @Override
  public boolean isViewFromObject(View view, Object object) {
    return view == object;
  }

  @Override
  public Object instantiateItem(ViewGroup container, int position) {
    ImageView imageView = mImageList.get(position % mImageList.size());
    imageView.setImageResource(mImageIds[position % mImageIds.length]);
    container.addView(imageView);
    return mImageList.get(position % mImageList.size());
  }

  @Override
  public void destroyItem(ViewGroup container, int position, Object object) {
    container.removeView(mImageList.get(position % mImageList.size()));
  }
}

act_loopviewpager.xml

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。