目前项目中需要用到ViewPager加载图片，现在在此记录一下。
首先先看布局文件：activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.fly.viewpagerbanner.MainActivity"> <android.support.v4.view.ViewPager android:id="@+id/viewpager" android:layout_above="@+id/ll" android:layout_width="fill_parent" android:layout_height="fill_parent" /> <LinearLayout android:id="@+id/ll" android:layout_marginTop="10.0dip" android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="24.0dip" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true"/> </RelativeLayout>
MainActivity
package com.example.fly.viewpagerbanner; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.Toast; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * 类名： * 类描述：ViewPager展示图片 * 创建人：fly * 创建日期： 2017/1/16. * 版本：V1.0 */ public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener,View.OnClickListener { private ViewPager vp; private ViewPagerAdapter vpAdapter; private List<Map<String, Object>> data; private int lastValue = -1; // 是不是最后一张图片 private ImageView[] dots; //底部小点图片 private int currentIndex; //记录当前选中位置 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Intent intent = new Intent(); // intent.putStringArrayListExtra("GalleryPlusActivity",ArrayList<String>); // 怎么传递集合 ArrayList<String> imageLists = getIntent().getStringArrayListExtra("GalleryPlusActivity"); // 动态获取展示图片的集合 data = getData(imageLists); vp = (ViewPager) findViewById(R.id.viewpager); vpAdapter = new ViewPagerAdapter(data,this); vp.setAdapter(vpAdapter); vp.addOnPageChangeListener(this); initDots();//初始化底部小点 } //这个方法长度是动态的，可以改成你从服务器获取的图片，这样数量就不确定啦 public List<Map<String, Object>> getData(ArrayList<String> imageLists) { List<Map<String, Object>> mData = new ArrayList<>(); // if (imageLists != null && imageLists.size() > 0) { // for (int i = 0; i < imageLists.size(); i++) { // Map<String, Object> map = new HashMap<>(); // map.put("url", imageLists.get(i)); // map.put("view", new ImageView(this)); // mData.add(map); // } // } Map<String, Object> map = new HashMap<>(); map.put("url", "http://img2.duitang.com/uploads/item/201207/19/20120719132725_UkzCN.jpeg"); map.put("view", new ImageView(this)); mData.add(map); Map<String, Object> map1 = new HashMap<>(); map1.put("url", "http://img4.duitang.com/uploads/item/201404/24/20140424195028_vtvZu.jpeg"); map1.put("view", new ImageView(this)); mData.add(map1); Map<String, Object> map2 = new HashMap<>(); map2.put("url", "http://download.pchome.net/wallpaper/pic-5041-8-240x320.jpg"); map2.put("view", new ImageView(this)); mData.add(map2); Map<String, Object> map3 = new HashMap<>(); map3.put("url", "http://www.mangowed.com/uploads/allimg/130425/572-130425105311304.jpg"); map3.put("view", new ImageView(this)); mData.add(map3); return mData; } private void initDots() { LinearLayout.LayoutParams mLayoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT); mLayoutParams.setMargins(3, 0, 3, 0); LinearLayout ll = (LinearLayout) findViewById(R.id.ll); dots = new ImageView[data.size()]; //循环取得小点图片 for (int i = 0; i < data.size(); i++) { dots[i] = new ImageView(this); dots[i].setLayoutParams(mLayoutParams); dots[i].setBackgroundResource(R.drawable.dot); dots[i].setEnabled(true);//都设为灰色 dots[i].setOnClickListener(this); dots[i].setTag(i);//设置位置tag，方便取出与当前位置对应 ll.addView(dots[i]); } currentIndex = 0; dots[currentIndex].setEnabled(false);//设置为白色，即选中状态 } private void setCurView(int position) { /**设置当前的引导页*/ if (position < 0 || position >= data.size()) {return;} vp.setCurrentItem(position); } private void setCurDot(int position) { /**设置当前引导小点的选中*/ if (position < 0 || position > data.size() - 1 || currentIndex == position) {return;} dots[position].setEnabled(false); dots[currentIndex].setEnabled(true); currentIndex = position; } @Override //当前页面被滑动时调用 public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { lastValue = position; } @Override public void onPageSelected(int position) { //当新的页面被选中时调用 setCurDot(position); //设置底部小点选中状态 } @Override public void onPageScrollStateChanged(int state) { //当滑动状态改变时调用 if(state == 0){ if(lastValue == data.size()-1){ Toast.makeText(this, "已经是最后一张了", Toast.LENGTH_SHORT).show(); } } } @Override public void onClick(View v) { int position = (Integer)v.getTag(); setCurView(position); setCurDot(position); } }
ViewPagerAdapter
package com.example.fly.viewpagerbanner; import android.content.Context; import android.support.v4.view.PagerAdapter; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import com.bumptech.glide.Glide; import com.bumptech.glide.load.engine.DiskCacheStrategy; import java.util.List; import java.util.Map; public class ViewPagerAdapter extends PagerAdapter { Context context; List<Map<String, Object>> viewLists; public ViewPagerAdapter(List<Map<String, Object>> lists, Context context) { this.viewLists = lists; this.context = context; } @Override public int getCount() { //获得size return viewLists.size(); } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public void destroyItem(ViewGroup view, int position, Object object) { //销毁Item ImageView x = (ImageView) viewLists.get(position).get("view"); x.setScaleType(ImageView.ScaleType.FIT_CENTER); view.removeView(x); } @Override public Object instantiateItem(ViewGroup view, int position){ //实例化Item ImageView imageView = (ImageView) viewLists.get(position).get("view"); imageView.setScaleType(ImageView.ScaleType.FIT_CENTER); Glide.with(context) .load(viewLists.get(position).get("url").toString()) // .placeholder(R.mipmap.new_default) .error(R.mipmap.ic_launcher) .diskCacheStrategy(DiskCacheStrategy.RESULT) .into(imageView); view.addView(imageView, 0); return viewLists.get(position).get("view"); } }
是不是很简单。
最后附上demo：http://xiazai.jb51.net/201701/yuanma/ViewPager(jb51.net).rar
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脚本之家。