Android中使用自定义view实现轮播图

先导依赖:(可以选择使用imageloder,或者gilde加载图片)

compile 'com.github.bumptech.glide:glide:3.6.1'
compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

-----------------MainActivity------------------

package com.example.earl.myviewpager_banner;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private Banner banner;
    private List<String> urls;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getSupportActionBar().hide();
        banner = (Banner) findViewById(R.id.banner);

        urls = new ArrayList<>();
        urls.add("http://img2.imgtn.bdimg.com/it/u=3585804305,763553611&fm=27&gp=0.jpg");
        urls.add("http://img0.imgtn.bdimg.com/it/u=3281146250,5393266&fm=27&gp=0.jpg");
        urls.add("http://img5.imgtn.bdimg.com/it/u=2496610138,254842195&fm=27&gp=0.jpg");
        urls.add("http://img5.imgtn.bdimg.com/it/u=2951375427,1212049814&fm=27&gp=0.jpg");
        

        //解耦
        banner.loadData(urls).display();//构建者模式返回对象本身


        banner.setBannerClicklistener(new Banner.BannerClicklistener() {
            @Override
            public void onClickListener(int pos) {

                Toast.makeText(MainActivity.this, "pos====" + pos, Toast.LENGTH_SHORT).show();
            }
        });


    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (banner != null) {
            banner.cancel();
            banner = null;

        }
    }
}

------------------Banner-------------------

package com.example.earl.myviewpager_banner;

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Handler;
import android.support.annotation.AttrRes;
import android.support.annotation.NonNull;
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.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.bumptech.glide.Glide;
import com.nostra13.universalimageloader.core.ImageLoader;
import java.util.ArrayList;
import java.util.List;

public class Banner extends FrameLayout implements ViewPager.OnPageChangeListener{

    private final int DELAY_TIME = 3000;//自动轮播时间
    private List<String> mUrls;
    private List<ImageView> mViewpagerViews;
    private List<ImageView> mDotImageviews;
    private Context context;
    private int size;//圆点的大小
    private int margin;//圆点的间距
    private int count;//viewpager中view的数量
    private ViewPager mViewPager;
    private LinearLayout mDotlayout;//圆点布局
    private MyPager mPagerAdapter;

    private int currentItem;//当前viewpager索引


    private Handler handler = new Handler();


    private BannerClicklistener mBannerClicklistener;


    public Banner(@NonNull Context context) {
        super(context);

        init(context, null);
    }

    public Banner(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public Banner(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
    }


    /**
     * 初始化数据
     *
     * @param context
     * @param attrs
     */
    private void init(Context context, AttributeSet attrs) {
        this.context = context;
        mUrls = new ArrayList<>();
        mViewpagerViews = new ArrayList<>();
        mDotImageviews = new ArrayList<>();
        //拿到自定义的属性数组
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Banner);
        //得到数组里的自定义的size（圆点大小）
        size = typedArray.getDimensionPixelSize(R.styleable.Banner_size, 10);
        //得到数组里的自定义的margin（圆点间距）
        margin = typedArray.getDimensionPixelSize(R.styleable.Banner_margin, 10);

        typedArray.recycle();//通知jvm的垃圾回收器，当你回收对象的时候，一定要把我回收了


        View view = LayoutInflater.from(context).inflate(R.layout.banner_layout, this, true);
//        addView(view);
//        View child = LayoutInflater.from(context).inflate(R.layout.banner_layout,null);
//        addView(child);
        mViewPager = view.findViewById(R.id.viewpager);
        mDotlayout = view.findViewById(R.id.layout_dot);

        //添加viewpager页面改变监听
        mViewPager.addOnPageChangeListener(this);


    }

    /**
     * 绘制自定义view的所有元素
     */
    public void display() {
        //绘制viewpager
        drawViewpager();
        //绘制圆点
        drawDots();
        //设置自动滚动
        setAuto();

    }

    /**
     * 设置自动滚动
     */
    private void setAuto() {
        handler.postDelayed(mTask, DELAY_TIME);
    }

    /**
     * 定时任务
     */
    Runnable mTask = new Runnable() {
        @Override
        public void run() {
            currentItem++;
            if (currentItem >= count) {
                currentItem = 0;
            }
            mViewPager.setCurrentItem(currentItem);
            handler.postDelayed(this, DELAY_TIME);
        }
    };

    /**
     * 传urls
     *
     * @param urls
     */
    public Banner loadData(List<String> urls) {
        this.mUrls = urls;
        this.count = urls.size();
        return this;
    }

    /**
     * 绘制圆点
     */
    private void drawDots() {

        for (int i = 0; i < count; i++) {

            ImageView iv = new ImageView(context);

            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(size, size);
            params.leftMargin = margin;
            params.rightMargin = margin;
            iv.setLayoutParams(params);

            mDotImageviews.add(iv);

            if (i == 0) {

                iv.setImageResource(R.drawable.dot_selected);
            } else {
                iv.setImageResource(R.drawable.dot_normal);
            }

            mDotlayout.addView(iv);
        }


    }


    private void drawViewpager() {
        for (int i = 0; i < count; i++) {
            ImageView iv = new ImageView(context);
            iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
            mViewpagerViews.add(iv);
        }
        if (mViewpagerViews != null) {
            mPagerAdapter = new MyPager();
            mViewPager.setAdapter(mPagerAdapter);
        }
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    /**
     * 切换页面的监听
     * @param position
     */
    @Override
    public void onPageSelected(int position) {

        for (int i = 0; i < count; i++) {
            if (i == position) {
                mDotImageviews.get(i).setImageResource(R.drawable.dot_selected);
            } else {
                mDotImageviews.get(i).setImageResource(R.drawable.dot_normal);
            }

        }

    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }


    class MyPager extends PagerAdapter {

        @Override
        public int getCount() {
            return mViewpagerViews.size();
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }

        @Override
        public Object instantiateItem(ViewGroup container, final int position) {

            ImageView view = mViewpagerViews.get(position);
            container.addView(view);

            view.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View view) {

                    //实现点击逻辑

                    mBannerClicklistener.onClickListener(position);
                }
            });

            System.out.println("urls:"+mUrls.get(position));

            ImageLoader.getInstance().displayImage(mUrls.get(position), view);
//            Glide.with(context)
//                    .load(mUrls.get(position))
//                    .into(view);
            return view;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView((View) object);
        }
    }

    /**
     * 处理自动轮播和手动滑动的冲突
     *
     * @param ev
     * @return
     */
    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        int action = ev.getAction();
        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_MOVE) {
            stopAuto();
        } else if (action == MotionEvent.ACTION_UP) {
            setAuto();
        }
        return super.dispatchTouchEvent(ev);
    }

    /**
     * 取消自动轮播任务
     */
    private void stopAuto() {
        handler.removeCallbacks(mTask);//取消任务
    }

    /**
     * 供外部调用者调用的接口类
     */
    public interface BannerClicklistener {
        void onClickListener(int pos);
    }

    /**
     * 供外部调用者初始化接口对象
     */
    public void setBannerClicklistener(BannerClicklistener bannerClicklistener) {
        this.mBannerClicklistener = bannerClicklistener;
    }

    //取消轮播任务
    public void cancel(){
        handler.removeCallbacks(mTask);
    }
}

-----------------App-----------------

package com.example.earl.myviewpager_banner;

import android.app.Application;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

public class App extends Application{

    @Override
    public void onCreate() {
        super.onCreate();

        init();
    }

    private void init() {
        DisplayImageOptions o = new DisplayImageOptions.Builder()
                .cacheInMemory(true)
                .cacheOnDisk(true)
                .build();

        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(this)
                .writeDebugLogs()
                .diskCacheFileNameGenerator(new Md5FileNameGenerator())
                .defaultDisplayImageOptions(o)
                .build();
        ImageLoader.getInstance().init(config);
    }
}

<----------在drawable中创建xml文件,绘制出小圆点----------->

------------dot_normal.xml------------

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="oval">
    <solid android:color="@android:color/white"></solid>
    <size android:height="10dp" android:width="10dp"/>
</shape>

-------------dot_selected.xml----------

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="oval">

    <solid android:color="@android:color/holo_green_dark"></solid>
    <size android:height="10dp" android:width="10dp"/>

</shape>

---------------activity_main.xml-------------

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:banner="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.earl.myviewpager_banner.MainActivity">

    <com.example.earl.myviewpager_banner.Banner
        android:id="@+id/banner"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:visibility="visible"
        banner:margin="10dp"
        banner:size="10dp"></com.example.earl.myviewpager_banner.Banner>
</LinearLayout>

--------------banner_layout.xml-------------

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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/viewpager"
        android:layout_width="match_parent"
        android:layout_height="200dp" />

    <LinearLayout
        android:id="@+id/layout_dot"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:gravity="center"
        android:orientation="horizontal"
        android:paddingBottom="10dp" />

</FrameLayout>

<------------在value中创建 attrs.xml----------->

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Banner">
        <attr name="size" format="dimension"/>
        <attr name="margin" format="dimension"/>
    </declare-styleable>
</resources>