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Android实现ViewPager无限循环效果(二)

2019-10-22 18:10:46
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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;/** * Created by XiaoMai on 2016/10/9 17:44. *  */public class LoopViewPagerDemo2Activity extends BaseActivity {  /**   * 更新图片的时间   */  private static final int UPDATE_TIME = 3 * 1000;  private ViewPager mViewPager;  private LoopViewPagerAdapter2 mAdapter;  /**   * 指示Point   */  private LinearLayout mLinearLayoutPonits;  /**   * 图片资源集合   */  private int[] mImageIds;  /**   * 图片集合   */  private List<ImageView> mImageList;  /**   * 当前广告的index   */  private int mCurrentPageIndex;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);  }  @Override  protected void initVariables() {    super.initVariables();    /**     * 初始化图片的资源id     */    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};    /**     * 添加ImageView     */    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;/** * Created by XiaoMai on 2016/10/9 17:53. */public class LoopViewPagerAdapter2 extends PagerAdapter {  private List<ImageView> mImageList;  private int[] mImageIds;  public LoopViewPagerAdapter2(List<ImageView> 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

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical">  <include    android:id="@+id/titleBar"    layout="@layout/my_app_bar" />  <android.support.v4.view.ViewPager    android:id="@+id/activity_loop_viewpager"    android:layout_width="match_parent"    android:layout_height="200dp"    android:layout_below="@id/titleBar" />  <LinearLayout    android:id="@+id/activity_ll_container"    android:layout_width="match_parent"    android:orientation="horizontal"    android:gravity="center"    android:background="@color/toast"    android:layout_alignBottom="@id/activity_loop_viewpager"    android:visibility="gone"    android:layout_height="40dp"/></RelativeLayout>

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VEVB武林网。


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