Android 轮番图

jar 

compile'com.android.support:recyclerview-v7:26+'

compile'com.github.bumptech.glide:glide:3.7.0'

权限

<uses-permission android:name="android:permissiont.INTERNET"/>

代码

1.自定义控件

importandroid.content.Context;

importandroid.os.Handler;

importandroid.os.Message;

importandroid.support.annotation.Nullable;

importandroid.support.v7.widget.LinearLayoutManager;

importandroid.support.v7.widget.LinearSnapHelper;

importandroid.support.v7.widget.RecyclerView;

importandroid.util.AttributeSet;

importandroid.view.MotionEvent;

importandroid.view.View;

importjava.util.Timer;

importjava.util.TimerTask;

/**

* Created by 周岩 on 17/8/24.

*/

public class BannerRecyclerView extends RecyclerView {

private static final intSCROLL=1;

private intstartX;

private intstartY;

privateHandlermHandler=newHandler() {

@Override

public void handleMessage(Message msg) {

super.handleMessage(msg);

switch(msg.what) {

caseSCROLL:

smoothScrollToPosition(++mCurrentPosition);

break;

}

}

};

private booleanisTouching=false;

private booleanisPlaying=false;

private intmPeriod=3500;

private TimermTimer;

private TimerTaskmTimerTask;

private RunnablemPlayTask=newRunnable() {

@Override

public voidrun() {

if(!isTouching) {

mHandler.sendEmptyMessage(SCROLL);

mHandler.postDelayed(this,mPeriod);

}

}

};;

public int getCurrentPosition() {

return mCurrentPosition;

}

public void setCurrentPosition(intcurrentPosition) {

mCurrentPosition= currentPosition;

}

private intmCurrentPosition;

public BannerRecyclerView(Context context) {

super(context);

}

public BannerRecyclerView(Context context,@NullableAttributeSet attrs) {

super(context, attrs);

newPagerSnapHelper().attachToRecyclerView(this);

addOnScrollListener(newOnScrollListener() {

@Override

public voidonScrollStateChanged(RecyclerView recyclerView,intnewState) {

super.onScrollStateChanged(recyclerView, newState);

switch(newState) {

caseRecyclerView.SCROLL_STATE_IDLE:

int firstVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition();

int lastVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastVisibleItemPosition();

if(lastVisibleItemPosition-firstVisibleItemPosition==2&&mCurrentPosition!=firstVisibleItemPosition+1){

mCurrentPosition=firstVisibleItemPosition+1;

}

break;

//                    case RecyclerView.SCROLL_STATE_DRAGGING:

//                        System.out.println("SCROLL_STATE_DRAGGING"+mLinearLayoutManager.findFirstVisibleItemPosition()+"");

//                        System.out.println("SCROLL_STATE_DRAGGING"+mLinearLayoutManager.findLastVisibleItemPosition()+"");

//                        break;

//                    case RecyclerView.SCROLL_STATE_SETTLING:

//                        System.out.println(mLinearLayoutManager.findFirstVisibleItemPosition()+"");

//                        System.out.println(mLinearLayoutManager.findLastVisibleItemPosition()+"");

//                        break;

}

}

});

}

public BannerRecyclerView(Context context,@NullableAttributeSet attrs,intdefStyle) {

this(context, attrs);

}

@Override

public boolean dispatchTouchEvent(MotionEvent ev) {

switch(ev.getAction()) {

caseMotionEvent.ACTION_DOWN:

isTouching=true;

startX= (int)ev.getX();

startY= (int)ev.getY();

getParent().requestDisallowInterceptTouchEvent(true);

mHandler.removeCallbacksAndMessages(null);

break;

caseMotionEvent.ACTION_MOVE:

intmoveX = (int) ev.getX();

intmoveY = (int) ev.getY();

intdisX = moveX -startX;

intdisY = moveY -startY;

booleanisHorizontalMove = Math.abs(disX) *1.5> Math.abs(disY);

getParent().requestDisallowInterceptTouchEvent(isHorizontalMove);

break;

caseMotionEvent.ACTION_CANCEL:

caseMotionEvent.ACTION_UP:

isTouching=false;

resetAutoScroll();

break;

}

return super.dispatchTouchEvent(ev);

}

private class PagerSnapHelperextendsLinearSnapHelper {

@Override

public intfindTargetSnapPosition(LayoutManager layoutManager,intvelocityX,intvelocityY) {

inttargetPos =super.findTargetSnapPosition(layoutManager, velocityX, velocityY);

finalView currentView = findSnapView(layoutManager);

if(targetPos != RecyclerView.NO_POSITION&& currentView !=null) {

intcurrentPos = layoutManager.getPosition(currentView);

intfirst = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();

intlast = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();

currentPos = targetPos < currentPos ? last : (targetPos > currentPos ? first : currentPos);

targetPos = targetPos < currentPos ? currentPos -1: (targetPos > currentPos ? currentPos +1: currentPos);

}

returntargetPos;

}

}

public void startAutoScroll() {

mHandler.postDelayed(mPlayTask,100);

}

public void resetAutoScroll(){

mHandler.postDelayed(mPlayTask,mPeriod);

}

}

2自定义控件引入布局文件中

activity_main

<LinearLayout 

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:background="#f2f2f2">

<com.example.mac.binnerdemo.view.BannerRecyclerView

android:id="@+id/brv_show"

android:visibility="visible"

android:layout_width="match_parent"

android:layout_height="180dp"

android:background="@color/white"/>

</LinearLayout>

item_rv

<RelativeLayout android:layout_width="match_parent"

android:layout_height="@dimen/dimen_180">

<ImageView android:id="@+id/iv_item_home"

android:scaleType="centerCrop"

android:layout_width="match_parent"

android:layout_height="match_parent"/>

</RelativeLayout>

3 代码

（1）工具类

importandroid.app.Activity;

importandroid.util.Log;

importandroid.widget.ImageView;

importcom.bumptech.glide.Glide;

importcom.example.mac.binnerdemo.R;

/**

*@author zhouyan

*/

public class GlideManager {

/**

* 渐显动画时间 ms

*/

private static final intduration=300;

private static final intplaceholder= R.drawable.img_index_top;//占位图

private static final intheader_placeholder= R.drawable.img_index_top;//圆形头像占位图

private static final interror=0;//加载失败图R.drawable.ls_logo

/**

* 加载网络图片

*

*@paramcontext

*@paramurl

*@paramiv

*/

public static void setNormalImage(Activity context, String url, ImageView iv) {

if(context !=null)

Glide.with(context.getApplicationContext())

.load(url)

.placeholder(placeholder)//加载之前的 默认占位图

.error(error)//图片无法加载时的 默认占位图

.crossFade(duration)//淡入淡出动画 默认300ms

.centerCrop()

.into(iv);

}

/**

* 加载本地图片

*

*@paramcontext

*@paramresId

*@paramiv

*/

public static void setNormalImage(Activity context,intresId, ImageView iv) {

if(context !=null)

Glide.with(context.getApplicationContext())

.load(resId)

.placeholder(placeholder)//加载之前的 默认占位图

.error(error)//图片无法加载时的 默认占位图

.crossFade(duration)//淡入淡出动画 默认300ms

.centerCrop()

.into(iv);

}

}

（2）activity 代码

importandroid.app.Activity;

importandroid.support.v7.app.AppCompatActivity;

importandroid.os.Bundle;

importandroid.support.v7.widget.LinearLayoutManager;

importandroid.support.v7.widget.RecyclerView;

importandroid.view.LayoutInflater;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.ImageView;

importcom.example.mac.binnerdemo.glide.GlideManager;

importcom.example.mac.binnerdemo.view.BannerRecyclerView;

importjava.util.ArrayList;

public class MainActivity extends AppCompatActivity {

private BannerRecyclerView mBannerRecyclerView;

private ArrayList<String> imageUrls;

private RecyclerView.Adapter mRVAdapter;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mBannerRecyclerView= (BannerRecyclerView) findViewById(R.id.brv_show);

imageUrls=newArrayList<String>();

imageUrls.add("http://img.taodiantong.cn/v55183/infoimg/2013-07/130720115322ky.jpg");

imageUrls.add("http://pic30.nipic.com/20130626/8174275_085522448172_2.jpg");

imageUrls.add("http://pic18.nipic.com/20111215/577405_080531548148_2.jpg");

imageUrls.add("http://pic15.nipic.com/20110722/2912365_092519919000_2.jpg");

imageUrls.add("http://pic.58pic.com/58pic/12/64/27/55U58PICrdX.jpg");

LinearLayoutManager mLinearLayoutManager =newLinearLayoutManager(this, LinearLayoutManager.HORIZONTAL,false);

mBannerRecyclerView.setLayoutManager(mLinearLayoutManager);

view(imageUrls,this);

}

private voidview(final ArrayList mBannerinfosBeanList,final Activity context) {

if(mBannerRecyclerView.getAdapter() ==null) {

mRVAdapter=newRecyclerView.Adapter() {

@Override

publicViewHolderRV onCreateViewHolder(ViewGroup parent,int viewType) {

ViewHolderRV holderRV =new ViewHolderRV(LayoutInflater.from(context).inflate(R.layout.item_rv, parent,false));

return holderRV;

}

@Override

public void onBindViewHolder(ViewHolderRV holder,int position) {

if(holder!=null){

if(mBannerinfosBeanList!=null&&mBannerinfosBeanList.size() !=0) {

position = position %mBannerinfosBeanList.size();

//"?width=400&height=220"能过减小图片大小

GlideManager.setNormalImage(context,mBannerinfosBeanList.get(position)+"?width=400&height=220", holder.mIv);

}else{

GlideManager.setNormalImage(context, R.drawable.img_index_top, holder.mIv);

}

}

}

@Override

public int getItemCount() {

returnInteger.MAX_VALUE>>2;

}

};

mBannerRecyclerView.setAdapter(mRVAdapter);

mBannerRecyclerView.setCurrentPosition(200* mBannerinfosBeanList.size() -1);

mBannerRecyclerView.scrollToPosition(mBannerRecyclerView.getCurrentPosition());

if(mBannerinfosBeanList.size()!=1)mBannerRecyclerView.startAutoScroll();

}

}

//适配器

private class ViewHolderRV extends RecyclerView.ViewHolder {

public ImageView mIv;

publicViewHolderRV(View itemView) {

super(itemView);

mIv= (ImageView) itemView.findViewById(R.id.iv_item_home);

}

}

}