實際項目中我們經常用到baner圖的輪播,那麼今天就給大家看下從我們項目裡抽離出來的這個輪播圖,供大家參考使用。
Demo位址:http://download.csdn.net/detail/wxk105/9728222
技術要點
- loopviewpager的使用
- 使用Imagerloader加載網絡圖檔
效果圖
loopview包直接複制到項目中
mainactivity.xml布局中引用
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="180dp">
<com.example.xiaoke.loopviewpagerdemo.loopview.LoopViewPager
android:id="@+id/vp_loop_act"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:cacheColorHint="@android:color/white"
android:divider="@null"
android:fadingEdge="none"
android:listSelector="@android:color/transparent"
android:scrollbars="none" />
<LinearLayout
android:id="@+id/ll_point"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="15dp"
android:layout_marginRight="10dp"
android:gravity="right"
android:orientation="horizontal" />
</RelativeLayout>
</LinearLayout>
mainactivity代碼塊
package com.example.xiaoke.loopviewpagerdemo;
import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import com.example.xiaoke.loopviewpagerdemo.loopview.LoopViewPager;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private LoopViewPager viewPager;
private LinearLayout ll_point;
private List<ImageBean> list=new ArrayList<>();//圖檔集合
private List<View> views = new ArrayList<View>();//點的集合
private LinearLayout.LayoutParams paramsL = new LinearLayout.LayoutParams(, );//設定每個點容器大小
private MyPageAdapter pageAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化控件
initview();
//初始化資料
initdata();
}
/**
* 初始化控件
*/
private void initview() {
viewPager= (LoopViewPager) findViewById(R.id.vp_loop_act);
ll_point= (LinearLayout) findViewById(R.id.ll_point);
}
/**
* 初始化資料
*/
private void initdata() {
ImageBean image=new ImageBean();
image.setUrl("http://news.cnhubei.com/xw/yl/201405/W020140530279662501386.jpg");
ImageBean image2=new ImageBean();
image2.setUrl("http://img0.imgtn.bdimg.com/it/u=3688010775,3049294081&fm=21&gp=0.jpg");
ImageBean image3=new ImageBean();
image3.setUrl("http://npic7.edushi.com/cn/zixun/zh-chs/2015-09/09/4f4842aa50924e2bb6cedff42d09ef4a.png");
list.add(image);
list.add(image2);
list.add(image3);
//圖檔集合,從背景直接傳回,前端接收
initMyPageAdapter(list);
viewPager.setAuto(true);
//設定監聽
viewPager.setOnPageChangeListener(getListener());
}
/***
* 初始化viewpager擴充卡
*
* @param imageBeanList
*/
private void initMyPageAdapter(List<ImageBean> imageBeanList) {
initPoint(imageBeanList);
if (pageAdapter == null) {
pageAdapter = new MyPageAdapter(MainActivity.this, imageBeanList);
if (viewPager != null) {
viewPager.setAdapter(pageAdapter);
}
} else {
pageAdapter.upData(imageBeanList);
}
}
/***
* 初始化點
* 可以根據圖檔多少自動增加點
*/
private void initPoint(List<ImageBean> list) {
views.clear();
ll_point.removeAllViews();
for (int i = ; i < ; i++) {
View view = new View(getApplicationContext());
//設定點的間距
paramsL.setMargins(dip2px(getApplicationContext(), ), , , );
view.setLayoutParams(paramsL);//設定點的顔色,預設從第一個開始
if (i == ) {
view.setBackgroundResource(R.drawable.point_focus);
} else {
view.setBackgroundResource(R.drawable.point_normal);
}
views.add(view);
ll_point.addView(view);
}
}
/***
* viewpager監聽
*
* @return
*/
@NonNull
private ViewPager.OnPageChangeListener getListener() {
return new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
//相應圖檔被選中,相應點變成被選中色
if (views.size() != && views.get(position) != null) {
for (int i = ; i < views.size(); i++) {
if (i == position) {
views.get(i).setBackgroundResource(R.drawable.point_focus);
} else {
views.get(i).setBackgroundResource(R.drawable.point_normal);
}
}
}
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
};
}
/**
* 根據手機的分辨率從 dp 的機關 轉成為 px(像素)
*
* @param context 上下文
* @param dpValue dp值
* @return
*/
private int dip2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + f);
}
}
ImageBean用于接收背景擷取的圖檔集合
這裡我直接使用的網絡圖檔
package com.example.xiaoke.loopviewpagerdemo;
/**
* 圖檔實體類
* Q164454216
* Created by xiaoke on 2017/1/3.
*/
public class ImageBean {
//隻需要一個位址即可
private String url;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
}
Mypageradapter viewpager擴充卡
package com.example.xiaoke.loopviewpagerdemo;
/**
* Created by xiaoke on 2016/6/3.
*/
import android.content.Context;
import android.graphics.Bitmap;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;
import java.util.ArrayList;
import java.util.List;
/***
* viewpageradapter
*/
public class MyPageAdapter extends PagerAdapter {
private List<ImageBean> list=new ArrayList<>();
private Context context;
// 圖檔緩存 預設 等
private DisplayImageOptions optionsImag = new DisplayImageOptions.Builder()
.considerExifParams(true)
.imageScaleType(ImageScaleType.EXACTLY)
.cacheInMemory(true)
.cacheOnDisk(true)
.bitmapConfig(Bitmap.Config.RGB_565).build();
public MyPageAdapter(Context context, List<ImageBean> list){
this.list=list;
this.context=context;
}
public void upData(List<ImageBean> list){
this.list=list;
notifyDataSetChanged();
}
@Override
public int getCount() {
// return bannerInfoList==null?0:bannerInfoList.size();
return list==null?:list.size();
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
@Override
public Object instantiateItem(final ViewGroup container, final int position) {
View view = View.inflate(context, R.layout.item_loop_viewpager_act, null);
ImageView iv_iamge = (ImageView) view.findViewById(R.id.iv_item_image);
//加載圖檔位址
ImageLoader.getInstance().displayImage(list.get(position).getUrl(),iv_iamge,optionsImag);
((ViewPager) container).addView(view);
return view;
}
@Override
public boolean isViewFromObject(View view, Object obj) {
return view == obj;
}
}
Imagerloader初始化,關于圖檔加載架構Imagerloader使用,我會專門開一篇部落格來講,今天就簡單把初始化,加載圖檔附上
初始化,需要在MyApplication中進行初始化
package com.example.xiaoke.loopviewpagerdemo;
import android.app.Application;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.QueueProcessingType;
/**
* Q164454216
* Created by xiaoke on 2017/1/3.
*/
public class MyApplication extends Application {
@Override
public void onCreate() {
super.onCreate();
//初始化imageloader
inistalImageLoader();
}
private void inistalImageLoader() {
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(
getApplicationContext())
.threadPriority(Thread.NORM_PRIORITY - )// 設定線程的優先級
.denyCacheImageMultipleSizesInMemory()// 當同一個Uri擷取不同大小的圖檔,緩存到記憶體時,隻緩存一個。預設會緩存多個不同的大小的相同圖檔
.discCacheFileNameGenerator(new Md5FileNameGenerator())// 設定緩存檔案的名字
.discCacheFileCount()// 緩存檔案的最大個數
.tasksProcessingOrder(QueueProcessingType.LIFO)// 設定圖檔下載下傳和顯示的工作隊列排序
.build();
// Initialize ImageLoader with configuration
ImageLoader.getInstance().init(config);
}
}
最後要增加清單檔案通路網絡權限
引用自建的application
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.xiaoke.loopviewpagerdemo" >
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:name=".MyApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme" >
<activity android:name=".MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
OK,是不是很簡單,很友善,快速使用起來吧。