前言
今天給大家帶來一個新的控件–輪播圖,網上已經有很多這類的博客來講解如何實現的,那么我的這個有哪些特點呢?或是說有哪些不同呢?
滿足了輪播圖的基本要求,循環滑動,在最后一張切到第一張時可以平穩的過渡
簡潔簡潔簡潔
擴展性強
如何使用
下面我們先展示兩種效果圖
1 默認效果

代碼實現
//布局代碼<com.landptf.view.BannerM android:id="@+id/bm_banner" android:layout_width="match_parent" android:layout_height="200dp" />//java代碼BannerM banner = (BannerM) findViewById(R.id.bm_banner);if (banner != null) { banner.setBannerBeanList(bannerList).show();}//初始化數據private void initData() { bannerList = new ArrayList<>(4); BannerBean banner1 = new BannerBean("測試圖片1", url1, ""); BannerBean banner2 = new BannerBean("測試圖片2", url2, ""); BannerBean banner3 = new BannerBean("測試圖片3", url3, ""); BannerBean banner4 = new BannerBean("測試圖片4", url4, ""); bannerList.add(banner1); bannerList.add(banner2); bannerList.add(banner3); bannerList.add(banner4);}其實關鍵代碼就一行,這里面用到了BannerBean的實體類,有三個參數,分別是圖片的描述文字,圖片地址,點擊后對應的鏈接
以上全部都是默認值,下面來看一下都哪些可以自定義
2 自定義效果

圖1和圖2主要有以下幾點不同
1 指示器和文字的位置結構,這里面我只實現了兩種,大家也可以下載源碼后擴展
2 圓點指示器選中后的顏色
3 自動播放的時間間隔
4 支持圖片未加載出來之前顯示默認圖片
自定義效果的代碼實現
下面通過xml和java代碼來分別演示一下圖2的實現
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();} 以上兩種代碼實現的效果完全等價,在java代碼中都是通過鏈式調用,使代碼看起來更加的簡潔。
有木有很方便,大大的減少了代碼量,而且是可以直接拿來用的。好了下面我們來看一下實現的代碼。
實現
圖片下載集成了Picasso,有對Picasso不熟悉的童鞋可以看一下我之前的博客圖片加載利器之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的引用代碼這里就不給出,大家可以訪問我的git查看,文末會給出地址
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. * 輪播圖控件 */public class BannerM extends RelativeLayout { /** * 圓點指示器的位置,文字在左,圓點在右 */ public static final int INDEX_POSITION_RIGHT = 0x100; /** * 圓點指示器的位置,文字在上,圓點在下 */ 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; //裝載ImageView控件的list private List<ImageView> ivList; //圓點指示器控件 private List<View> vList; //控制圓點View的形狀,未選中的顏色 private GradientDrawable gradientDrawable; //控制圓點View的形狀,選中的顏色 private GradientDrawable gradientDrawableSelected; //選中圓點的顏色值,默認為#FF3333 private int indexColorResId; //圖片對應的文字描述 private TextView tvText; //自動滑動的定時器 private ScheduledExecutorService scheduledExecutorService; //當前加載到第幾頁 private int currentIndex = 0; //默認背景圖 private int defaultImageResId; private Drawable defaultImageDrawable = null; //自動輪播的時間間隔(s) private int intervalTime = 5; //輪播圖需要的數據列表 private List<BannerBean> bannerBeanList; //圓點指示器的位置,提供兩種布局 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(); } } /** * 設置圖片加載之前默認顯示的圖片 * * @param defaultImageResId * @return BannerM */ public BannerM setDefaultImageResId(int defaultImageResId) { this.defaultImageResId = defaultImageResId; return this; } /** * 設置圖片加載之前默認顯示的圖片 * * @param defaultImageDrawable * @return BannerM */ public BannerM setDefaultImageDrawable(Drawable defaultImageDrawable) { this.defaultImageDrawable = defaultImageDrawable; return this; } /** * 設置輪播的時間間隔,單位為s,默認為5s * * @param intervalTime * @return BannerM */ public BannerM setIntervalTime(int intervalTime) { this.intervalTime = intervalTime; return this; } /** * 設置圓點指示器的位置 * #BannerM.INDEX_POSITION_RIGHT or #BannerM.INDEX_POSITION_BOTTOM * * @param indexPosition * @return BannerM */ public BannerM setIndexPosition(int indexPosition) { this.indexPosition = indexPosition; return this; } /** * 選中圓點的顏色值,默認為#FF3333 * * @param indexColor * @return BannerM */ public BannerM setIndexColor(int indexColor) { this.indexColorResId = indexColor; return this; } /** * 設置輪播圖需要的數據列表 * * @param bannerBeanList * @return BannerM */ public BannerM setBannerBeanList(List<BannerBean> bannerBeanList) { this.bannerBeanList = bannerBeanList; return this; } /** * 設置圖片的點擊事件 * @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); //定時器開始工作 startPlay(); } /** * 初始化圓點指示器,根據indexPosition來加載不同的布局 */ 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); } //默認第一張圖片的文字描述 tvText.setText(bannerBeanList.get(0).getText()); //使用GradientDrawable構造圓形控件 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下載圖片,只在SdCard中緩存 */ 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); } /** * 獲取點擊圖片的位置 * @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); }}這篇文章就介紹到這里了,點擊這里查看源碼
下面是測試用的圖片:



以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支持VEVB武林網。
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