前言

今天给大家带来一个新的控件–轮播图，网上已经有很多这类的博客来讲解如何实现的，那么我的这个有哪些特点呢？或是说有哪些不同呢？

满足了轮播图的基本要求，循环滑动，在最后一张切到第一张时可以平稳的过渡
简洁简洁简洁
扩展性强

如何使用

下面我们先展示两种效果图

1 默认效果

代码实现

//布局代码<com.landptf.view.BannerM android:id="@+id/bm_banner" android:layout_width="match_parent" android:layout_height="200dp" />//java代码BannerM banner = (BannerM) findViewById(R.id.bm_banner);if (banner != null) { banner.setBannerBeanList(bannerList).show();}//初始化数据private void initData() { bannerList = new ArrayList<>(4); BannerBean banner1 = new BannerBean("测试图片1", url1, ""); BannerBean banner2 = new BannerBean("测试图片2", url2, ""); BannerBean banner3 = new BannerBean("测试图片3", url3, ""); BannerBean banner4 = new BannerBean("测试图片4", url4, ""); bannerList.add(banner1); bannerList.add(banner2); bannerList.add(banner3); bannerList.add(banner4);}

其实关键代码就一行，这里面用到了BannerBean的实体类，有三个参数，分别是图片的描述文字，图片地址，点击后对应的链接

以上全部都是默认值，下面来看一下都哪些可以自定义

2 自定义效果

图1和图2主要有以下几点不同

1 指示器和文字的位置结构，这里面我只实现了两种，大家也可以下载源码后扩展
2 圆点指示器选中后的颜色
3 自动播放的时间间隔
4 支持图片未加载出来之前显示默认图片

自定义效果的代码实现

下面通过xml和java代码来分别演示一下图2的实现

1 xml

<com.landptf.view.BannerM android:id="@+id/bm_banner" android:layout_width="match_parent" android:layout_height="200dp" landptf:defaultImageDrawable="@drawable/default_image" landptf:intervalTime="3" landptf:indexPosition="bottom" landptf:indexColor="@color/colorPrimary" />BannerM banner = (BannerM) findViewById(R.id.bm_banner);if (banner != null) { banner.setBannerBeanList(bannerList) .setOnItemClickListener(new BannerM.OnItemClickListener() { @Override public void onItemClick(int position) { Log.e("landptf", "position = " + position); } }) .show();}

2 java

<com.landptf.view.BannerM android:id="@+id/bm_banner" android:layout_width="match_parent" android:layout_height="200dp" />BannerM banner = (BannerM) findViewById(R.id.bm_banner);if (banner != null) { banner.setBannerBeanList(bannerList) .setDefaultImageResId(R.drawable.default_image) .setIndexPosition(BannerM.INDEX_POSITION_BOTTOM) .setIndexColor(getResources().getColor(R.color.colorPrimary)) .setIntervalTime(3) .setOnItemClickListener(new BannerM.OnItemClickListener() { @Override public void onItemClick(int position) { Log.e("landptf", "position = " + position); } }) .show();}

以上两种代码实现的效果完全等价，在java代码中都是通过链式调用，使代码看起来更加的简洁。
有木有很方便，大大的减少了代码量，而且是可以直接拿来用的。好了下面我们来看一下实现的代码。

实现

图片下载集成了Picasso，有对Picasso不熟悉的童鞋可以看一下我之前的博客图片加载利器之Picasso（二）基本用法

<?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.support.v4.view.ViewPager android:id="@+id/vp_banner" android:layout_width="match_parent" android:layout_height="match_parent" /> <ViewStub android:id="@+id/vs_index_right" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout="@layout/viewstub_banner_m_index_right" /> <ViewStub android:id="@+id/vs_index_bottom" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout="@layout/viewstub_banner_m_index_bottom" /></RelativeLayout>

ViewStub的引用代码这里就不给出，大家可以访问我的git查看，文末会给出地址

package com.landptf.view;import android.annotation.SuppressLint;import android.content.Context;import android.content.res.ColorStateList;import android.content.res.TypedArray;import android.graphics.drawable.Drawable;import android.graphics.drawable.GradientDrawable;import android.os.Handler;import android.os.Message;import android.os.Parcelable;import android.support.annotation.Nullable;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.util.AttributeSet;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.view.ViewParent;import android.view.ViewStub;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.RelativeLayout;import android.widget.TextView;import com.landptf.R;import com.landptf.bean.BannerBean;import com.landptf.util.ConvertM;import com.squareup.picasso.MemoryPolicy;import com.squareup.picasso.Picasso;import java.util.ArrayList;import java.util.List;import java.util.concurrent.Executors;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit;/** * Created by landptf on 2017/03/06. * 轮播图控件 */public class BannerM extends RelativeLayout { /** * 圆点指示器的位置，文字在左，圆点在右 */ public static final int INDEX_POSITION_RIGHT = 0x100; /** * 圆点指示器的位置，文字在上，圆点在下 */ public static final int INDEX_POSITION_BOTTOM = 0x101; private static final int HANDLE_UPDATE_INDEX = 0; private Context mContext; private ViewPager vpBanner; private ViewPagerAdapter adapter; private OnItemClickListener mOnItemClickListener; //装载ImageView控件的list private List<ImageView> ivList; //圆点指示器控件 private List<View> vList; //控制圆点View的形状，未选中的颜色 private GradientDrawable gradientDrawable; //控制圆点View的形状，选中的颜色 private GradientDrawable gradientDrawableSelected; //选中圆点的颜色值，默认为#FF3333 private int indexColorResId; //图片对应的文字描述 private TextView tvText; //自动滑动的定时器 private ScheduledExecutorService scheduledExecutorService; //当前加载到第几页 private int currentIndex = 0; //默认背景图 private int defaultImageResId; private Drawable defaultImageDrawable = null; //自动轮播的时间间隔(s) private int intervalTime = 5; //轮播图需要的数据列表 private List<BannerBean> bannerBeanList; //圆点指示器的位置，提供两种布局 private int indexPosition = INDEX_POSITION_RIGHT; public BannerM(Context context) { this(context, null); } public BannerM(Context context, AttributeSet attrs) { this(context, attrs, 0); } public BannerM(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context, attrs, defStyleAttr); } private void init(Context context, AttributeSet attrs, int defStyle) { mContext = context; LayoutInflater.from(context).inflate(R.layout.view_banner_m, this, true); vpBanner = (ViewPager) findViewById(R.id.vp_banner); TypedArray a = getContext().obtainStyledAttributes( attrs, R.styleable.bannerM, defStyle, 0); if (a != null) { defaultImageDrawable = a.getDrawable(R.styleable.bannerM_defaultImageDrawable); intervalTime = a.getInteger(R.styleable.bannerM_intervalTime, 5); indexPosition = a.getInteger(R.styleable.bannerM_indexPosition, INDEX_POSITION_RIGHT); ColorStateList indexColorList = a.getColorStateList(R.styleable.bannerM_indexColor); if (indexColorList != null) { indexColorResId = indexColorList.getColorForState(getDrawableState(), 0); } a.recycle(); } } /** * 设置图片加载之前默认显示的图片 * * @param defaultImageResId * @return BannerM */ public BannerM setDefaultImageResId(int defaultImageResId) { this.defaultImageResId = defaultImageResId; return this; } /** * 设置图片加载之前默认显示的图片 * * @param defaultImageDrawable * @return BannerM */ public BannerM setDefaultImageDrawable(Drawable defaultImageDrawable) { this.defaultImageDrawable = defaultImageDrawable; return this; } /** * 设置轮播的时间间隔，单位为s，默认为5s * * @param intervalTime * @return BannerM */ public BannerM setIntervalTime(int intervalTime) { this.intervalTime = intervalTime; return this; } /** * 设置圆点指示器的位置 * #BannerM.INDEX_POSITION_RIGHT or #BannerM.INDEX_POSITION_BOTTOM * * @param indexPosition * @return BannerM */ public BannerM setIndexPosition(int indexPosition) { this.indexPosition = indexPosition; return this; } /** * 选中圆点的颜色值，默认为#FF3333 * * @param indexColor * @return BannerM */ public BannerM setIndexColor(int indexColor) { this.indexColorResId = indexColor; return this; } /** * 设置轮播图需要的数据列表 * * @param bannerBeanList * @return BannerM */ public BannerM setBannerBeanList(List<BannerBean> bannerBeanList) { this.bannerBeanList = bannerBeanList; return this; } /** * 设置图片的点击事件 * @param listener */ public BannerM setOnItemClickListener(@Nullable OnItemClickListener listener) { mOnItemClickListener = listener; return this; } public void show() { if (bannerBeanList == null || bannerBeanList.size() == 0) { throw new IllegalArgumentException("bannerBeanList == null"); } initImageViewList(); initIndexList(); vpBanner.addOnPageChangeListener(new OnPageChangeListener()); adapter = new ViewPagerAdapter(); vpBanner.setAdapter(adapter); //定时器开始工作 startPlay(); } /** * 初始化圆点指示器，根据indexPosition来加载不同的布局 */ private void initIndexList() { int count = bannerBeanList.size(); vList = new ArrayList<>(count); LinearLayout llIndex; if (indexPosition == INDEX_POSITION_RIGHT) { ViewStub vsIndexRight = (ViewStub) findViewById(R.id.vs_index_right); vsIndexRight.inflate(); llIndex = (LinearLayout) findViewById(R.id.ll_index_right); tvText = (TextView) findViewById(R.id.tv_text); } else { ViewStub vsIndexBottom = (ViewStub) findViewById(R.id.vs_index_bottom); vsIndexBottom.inflate(); llIndex = (LinearLayout) findViewById(R.id.ll_index_bottom); tvText = (TextView) findViewById(R.id.tv_text); } //默认第一张图片的文字描述 tvText.setText(bannerBeanList.get(0).getText()); //使用GradientDrawable构造圆形控件 gradientDrawable = new GradientDrawable(); gradientDrawable.setShape(GradientDrawable.OVAL); gradientDrawable.setColor(mContext.getResources().getColor(R.color.text)); gradientDrawableSelected = new GradientDrawable(); gradientDrawableSelected.setShape(GradientDrawable.OVAL); if (indexColorResId != 0) { gradientDrawableSelected.setColor(indexColorResId); } else { gradientDrawableSelected.setColor(mContext.getResources().getColor(R.color.mainColor)); } for (int i = 0; i < count; i++) { View view = new View(mContext); LinearLayout.LayoutParams lpView = new LinearLayout.LayoutParams(ConvertM.dp2px(mContext, 8), ConvertM.dp2px(mContext, 8)); lpView.rightMargin = ConvertM.dp2px(mContext, 4); view.setLayoutParams(lpView); if (0 == i) { view.setBackgroundDrawable(gradientDrawableSelected); } else { view.setBackgroundDrawable(gradientDrawable); } view.bringToFront(); vList.add(view); llIndex.addView(view); } } /** * 初始化ImageView，使用Picasso下载图片，只在SdCard中缓存 */ private void initImageViewList() { int count = bannerBeanList.size(); ivList = new ArrayList<>(count); for (int i = 0; i < count; i++) { final ImageView imageView = new ImageView(mContext); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); ivList.add(imageView); imageView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { mOnItemClickListener.onItemClick(getPosition(imageView)); } }); if (defaultImageResId != 0) { Picasso.with(mContext) .load(bannerBeanList.get(i).getUrl()) .placeholder(defaultImageResId) .memoryPolicy(MemoryPolicy.NO_CACHE, MemoryPolicy.NO_STORE) .into(imageView); } else if (defaultImageDrawable != null) { Picasso.with(mContext) .load(bannerBeanList.get(i).getUrl()) .placeholder(defaultImageDrawable) .memoryPolicy(MemoryPolicy.NO_CACHE, MemoryPolicy.NO_STORE) .into(imageView); } else { Picasso.with(mContext) .load(bannerBeanList.get(i).getUrl()) .memoryPolicy(MemoryPolicy.NO_CACHE, MemoryPolicy.NO_STORE) .into(imageView); } } } private void startPlay() { scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(); scheduledExecutorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { currentIndex++; handler.obtainMessage(HANDLE_UPDATE_INDEX).sendToTarget(); } }, intervalTime, intervalTime, TimeUnit.SECONDS); } /** * 获取点击图片的位置 * @param item * @return int */ private int getPosition(ImageView item) { for (int i = 0; i < ivList.size(); i++) { if (item == ivList.get(i)) { return i; } } return -1; } @SuppressLint("HandlerLeak") private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case HANDLE_UPDATE_INDEX: vpBanner.setCurrentItem(currentIndex); break; default: break; } } }; private class OnPageChangeListener implements ViewPager.OnPageChangeListener { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { currentIndex = position; for (int i = 0; i < bannerBeanList.size(); i++) { if (position % ivList.size() == i) { vList.get(i).setBackgroundDrawable(gradientDrawableSelected); } else { vList.get(i).setBackgroundDrawable(gradientDrawable); } tvText.setText(bannerBeanList.get(position % ivList.size()).getText()); } } @Override public void onPageScrollStateChanged(int state) { } } private class ViewPagerAdapter extends PagerAdapter { @Override public void destroyItem(View container, int position, Object object) { } @Override public Object instantiateItem(View container, int position) { position %= ivList.size(); if (position<0){ position = ivList.size()+position; } ImageView imageView = ivList.get(position); ViewParent vp =imageView.getParent(); if (vp!=null){ ViewGroup parent = (ViewGroup)vp; parent.removeView(imageView); } ((ViewPager) container).addView(imageView); return imageView; } @Override public int getCount() { return Integer.MAX_VALUE; } @Override public boolean isViewFromObject(View arg0, Object arg1) { return arg0 == arg1; } @Override public void restoreState(Parcelable arg0, ClassLoader arg1) { } @Override public Parcelable saveState() { return null; } @Override public void startUpdate(View arg0) { } @Override public void finishUpdate(View arg0) { } } public interface OnItemClickListener { void onItemClick(int position); }}

这篇文章就介绍到这里了，点击这里查看源码

下面是测试用的图片：

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。