年底忙碌起來便擠不出時間更新筆記文章了还惠，趁今天周末抽空把之前的功能筆記補齊O(∩_∩)O哈哈~
記錄到這個功能我首先要感謝一下我目前的老大對我的幫助糙申，一位英俊瀟灑風(fēng)流倜儻陽光幽默精通各大代碼域的帥小伙guthub:https://github.com/KnifeStone

一.概述 ：

EventBus是針對Android優(yōu)化的發(fā)布/訂閱事件總線。主要是替代Intent/Handler/BroadCast在Fragment/Activity/Service線程之間傳遞消息嚣伐。開銷小，代碼更優(yōu)雅，將發(fā)送者和接收者解耦策严。

二.推薦：

針EventBus的簡單用法推薦（作者寫得通俗易懂）
http://blog.csdn.net/harvic880925/article/details/40660137
更深入了解EventBus推薦
http://www.reibang.com/p/31e3528ca7e5

(1). EventBus官網(wǎng)地址
(2). EventBus github地址
(3). EventBus 3.0的用法詳解

三.實現(xiàn)步驟：

按照以往的慣例先上效果圖：

GIF.gif

看完效果圖可以知道實現(xiàn)添加購物車分為幾部分：
首先先簡單寫一個產(chǎn)品列表，數(shù)據(jù)是存儲在七牛云上面的臨時數(shù)據(jù)饿敲，先拿來用妻导。

github下載地址，歡迎star：https://github.com/LXLYHM/EventBusAddShoppingCart/blob/master/README.md

代碼注釋比較詳細(xì)怀各，感興趣的小伙伴可以下載看看倔韭，下面直接上干貨，就不多解釋廢話了

1.網(wǎng)絡(luò)框架：是自封裝的一個非常簡單的Retrofit2網(wǎng)絡(luò)框架
2.重點主要在加入購物車的時候使用EventBus全局通知事件上

首先是在總工程的build.gradle接入開源庫資源：

allprojects {
    repositories {
        jcenter()
        mavenCentral()
        maven { url 'https://jitpack.io' }
    }
}

然后在app的build.gradle引用開源庫：

compile 'org.greenrobot:eventbus:3.0.0'

在基類AddCartActivity.java里面注冊關(guān)閉好EventBus和實現(xiàn)加入購物車動畫給MainActivity.java繼承：

public abstract class AddCartActivity extends AppCompatActivity {

    protected QBadgeView qBadgeView = null;//購物車數(shù)量紅點
    protected ObjectAnimator animator = null;//動畫view

    @Override
    protected void onStart() {
        super.onStart();
        //onStart的時候注冊EventBus
        if (!EventBus.getDefault().isRegistered(this)) {
            EventBus.getDefault().register(this);
        }
    }

    @Override
    protected void onStop() {
        super.onStop();
        //onStop的時候釋放EventBus
        EventBus.getDefault().unregister(this);
    }

    //發(fā)送消息線程
    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onMessageEvent(ProductAnimEvent event) {
        if (qBadgeView == null) {
            return;
        }
        View view = event.view;
        //獲取商品坐標(biāo)
        int[] goodsPoint = new int[2];
        view.getLocationInWindow(goodsPoint);
        //獲取購物車坐標(biāo)
        int[] shoppingCartPoint = new int[2];
        qBadgeView.getLocationInWindow(shoppingCartPoint);
        //生成商品View 并播放商品加入購物車動畫
        ProductAnimView animView = new ProductAnimView(this);
        ImageLoader.getInstance().loadRound(event.imgPath, animView);
        animView.setCircleStartPoint(goodsPoint[0] + view.getWidth() / 2 - ConvertUtils.dp2px(24f), goodsPoint[1] + view.getHeight() / 2 - ConvertUtils.dp2px(24f));
        animView.setCircleEndPoint(shoppingCartPoint[0], shoppingCartPoint[1] - ConvertUtils.dp2px(24f));
        ViewGroup decorView = (ViewGroup) getWindow().getDecorView();
        decorView.addView(animView, ConvertUtils.dp2px(48f), ConvertUtils.dp2px(48f));
        animView.startAnimation();
        //判斷是否播放小紅點跳躍動畫
        if (animator == null && qBadgeView != null) {
            animator = ObjectAnimator.ofFloat(qBadgeView, "translationY", 0f, -ConvertUtils.dp2px(6f), 0f);
            animator.setDuration(300);
        }
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                if (animator.isRunning()) {
                    return;
                }
                animator.start();
            }
        }, 500);
    }
}

封裝AppCart.java作為輔助類：

public class AppCart {
    //購物車
    private static List<ProductListBean> mList;

    public static List<ProductListBean> getCartList() {
        if (mList == null) {
            mList = new ArrayList<>();
        }
        if (mList.isEmpty()) {
            mList = (List<ProductListBean>) CacheUtils.getInstance().getSerializable("cacheCart");
            if (mList == null) {
                mList = new ArrayList<>();
            }
        }
        return mList;
    }

    /**
     * 單個商品數(shù)量變化 先改變后傳入
     */
    public static void onChangeOne(ProductListBean bean) {
        if (bean == null) {
            return;
        }
        if (mList == null) {
            getCartList();
        }
        int index;
        if (mList.contains(bean)) {
            index = mList.indexOf(bean);
            mList.get(index).buy_num = bean.buy_num;
            if (mList.get(index).buy_num <= 0) {
                mList.remove(bean);
            }
        } else {
            mList.add(0, bean);
        }
        putCartList(mList);
    }

    /**
     * 獲得購物車數(shù)量
     */
    public static int getCartNumber() {
        if (getCartList()==null || getCartList().isEmpty()) {
            return 0;
        }
        int number = 0;
        for (ProductListBean productBean : mList) {
            number += productBean.buy_num;
        }
        return number;
    }

    /**
     * 寫入緩存
     */
    public static void putCartList(List<ProductListBean> cartList) {
        mList = cartList;
        //發(fā)送廣播
        EventBus.getDefault().post(new CartEvent());
    }

    /**
     * 移除一樣商品
     */
    public static void onRemove(ProductListBean bean) {
        if (bean == null) {
            return;
        }
        bean.buy_num = 0;
        mList.remove(bean);
        putCartList(mList);
    }

    /**
     * 清除補貨清單
     */
    public static void clear() {
        if (getCartList()==null || getCartList().isEmpty()) {
            return;
        }
        CacheUtils.getInstance().remove("cacheCart");
        mList.clear();
    }

    /**
     * 比對數(shù)據(jù)
     * @param list
     * @return true有比對 false無比對
     */
    public static boolean comparison(List<ProductListBean> list) {
        List<ProductListBean> listCart = getCartList();
        if (list == null || list.size() == 0) {
            return false;
        }
        if (listCart == null || listCart.size() == 0) {
            for (ProductListBean productBean : list) {
                productBean.buy_num = 0;
            }
            return true;
        }
        int index;
        for (ProductListBean productBean : list) {
            if (listCart.contains(productBean)) {
                index = listCart.indexOf(productBean);
                productBean.buy_num = listCart.get(index).buy_num;
            } else {
                productBean.buy_num = 0;
            }
        }
        return true;
    }
}

接下來就是最重要的MainActivity.java了：

/**
 * Created by LXL on 2017/12/8.
 * http://my.csdn.net/lxlyhm
 * https://github.com/LXLYHM
 * http://www.reibang.com/u/8fd63a0d4c4c
 * 購物車
 */
public class MainActivity extends AddCartActivity {

    private RecyclerView mRecyclerView;
    private List<ProductListBean> mList = new ArrayList();
    private ProductAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //狀態(tài)欄全局默認(rèn)統(tǒng)一成白底黑字
        ImmersionBar.with(this).statusBarColor(R.color.colorPrimary).fitsSystemWindows(true).init();
        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
        mAdapter = new ProductAdapter();
        mRecyclerView.setAdapter(mAdapter);
        mAdapter.setNewData(mList);

        initData();
    }

    /**
     * 加載數(shù)據(jù)
     */
    private void initData() {
        new AppData().getData(new CallBackAdapter<String>() {
            @Override
            public void onSuccess(String object) {
                List<ProductListBean> list = new Gson().fromJson(object, new TypeToken<List<ProductListBean>>() {}.getType());
                AppCart.comparison(list);
                mList = list;
                mAdapter.setNewData(mList);
            }

            @Override
            public void onFailure(int code, String message) {
            }

            @Override
            public void onCompleted() {
            }
        });
    }

    /**
     * 顯示狀態(tài)
     */
    public void checkState() {
        if (AppCart.getCartNumber() <= 0) {
            if (qBadgeView != null) {
                qBadgeView.hide(true);
            }
        } else {
            //動畫
            if (qBadgeView == null) {
                View view = findViewById(R.id.containerBageView);
                qBadgeView = new QBadgeView(this);
                qBadgeView.setGravityOffset(0f, ConvertUtils.dp2px(6f), false).bindTarget(view);
            }
            qBadgeView.setBadgeNumber(AppCart.getCartNumber());
        }
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onMessageEvent(CartEvent event) {
        checkState();
    }

    @Override
    protected void onStart() {
        super.onStart();
        checkState();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        AppCart.clear();//清除
        ImmersionBar.with(this).destroy();
    }
}

ProductAdapter.java：

public class ProductAdapter extends BaseQuickAdapter<ProductListBean, BaseViewHolder> {

    public ProductAdapter(){
        super(R.layout.item_product);
    }

    @Override
    protected void convert(final BaseViewHolder helper, final ProductListBean item) {
        helper.setText(R.id.productsName, item.name);
        ImageLoader.getInstance().load(item.cover_image_url, (ImageView) helper.getView(R.id.imgProducts));

        final MyEditText etNumber = helper.getView(R.id.et_number);//數(shù)量
        etNumber.clearFocus();//清除焦點
        etNumber.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (MotionEvent.ACTION_DOWN == event.getAction()) {
                    etNumber.setCursorVisible(true);// 再次點擊顯示光標(biāo)
                }
                return false;
            }
        });

        etNumber.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                if (!"".equals(s.toString())) {
                    int buy_num = parseInt(s.toString());
                    item.buy_num = buy_num;
                    if (buy_num > 0) {
                        AppCart.onChangeOne(item);//發(fā)送購物車變化
                    }
                    if (buy_num == 0){
                        AppCart.onRemove(item);
                    }
                }
            }

            @Override
            public void afterTextChanged(Editable s) {
            }
        });
        etNumber.setText(item.buy_num + "");
        // 加
        helper.getView(R.id.bt_add).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                item.buy_num++;
                if (item.buy_num > 0){
                    EventBus.getDefault().post(new ProductAnimEvent(helper.getView(R.id.imgProducts), item.cover_image_url));
                }
                etNumber.setText(item.buy_num + "");
            }
        });
        // 減
        helper.getView(R.id.bt_float).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (item.buy_num == 0) {
                    return;
                }
                item.buy_num--;
                etNumber.setText(item.buy_num + "");
            }
        });
    }
}

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