使用RXjava封装通用的轮选择控件

滚轮控件在我们的项目开发中经常会用到，在这里给大家推荐一个不错的滚轮控件EasyPickerView，这个控件的优点有：轻量化，只有一个类400多行代码，文字显示效果可以自定义，可自定义文字透明度和大小。

首先这个控件大家下载下来后，可以在原控件的基础上稍加修改，因为控件显示的数据类型限制为了String，这肯定不能满足我们项目的需求，要是我们的数据源为List<Model>呢，难道还需要将List<Model>转换为List<String>吗，这肯定是非常繁琐的。

改造之前的代码

   //50行
   private ArrayList<String> dataList = new ArrayList<>();

   // 252行
    Paint.FontMetrics tempFm = textPaint.getFontMetrics();
    String text = dataList.get(index);
    float textWidth = textPaint.measureText(text);
    canvas.drawText(text, cx - textWidth / 2, tempY - (tempFm.ascent + tempFm.descent) / 2, textPaint);
 
   //345行
    public void setDataList(ArrayList<String> dataList) {
        this.dataList.clear();
        this.dataList.addAll(dataList);

        // 更新maxTextWidth
        if (null != dataList && dataList.size() > 0) {
            int size = dataList.size();
            for (int i = 0; i < size; i++) {
                float tempWidth = textPaint.measureText(dataList.get(i));
                if (tempWidth > maxTextWidth)
                    maxTextWidth = tempWidth;
            }
            curIndex = 0;
        }
        requestLayout();
        invalidate();
    }

改造之后的代码

    private ArrayList<Object> dataList = new ArrayList<>();

    Object text = dataList.get(index);
    float textWidth = textPaint.measureText(text.toString());
    canvas.drawText(text.toString(), cx - textWidth / 2, tempY - (tempFm.ascent + tempFm.descent) / 2, textPaint);

    public <T extends Object> void setDataList(List<T> dataList) {
        this.dataList.clear();
        this.dataList.addAll(dataList);

        // 更新maxTextWidth
        if (null != dataList && dataList.size() > 0) {
            int size = dataList.size();
            for (int i = 0; i < size; i++) {
                float tempWidth = textPaint.measureText(dataList.get(i).toString());
                if (tempWidth > maxTextWidth)
                    maxTextWidth = tempWidth;
            }
            curIndex = 0;
        }
        requestLayout();
        invalidate();
    }

经过这些调整后，这个控件可以显示所有的数据类型了，只需被设置的对象实现toString()即可。好了，接下来就是结合RxJava对控件进行封装了，封装的前提肯定是需要引用RxJava的，这里对Rxjava就不做介绍了，网上相应的文章很多，这里直接上封装好的代码。

public class MyWhellView extends Dialog implements View.OnClickListener {

    EasyPickerView whellView;

    List mDatas;

    private Observable observable;

    private ObservableEmitter observableEmitter;

    public MyWhellView(@NonNull Context context) {
        super(context, R.style.common_diallog_style);
        initView();
    }


    private void initView() {
        View rootView = XYJUiUtil.inflate(R.layout.my_whell);

        LinearLayout contentView = (LinearLayout) rootView.findViewById(R.id.ll_vessel);

        whellView = (EasyPickerView) contentView.findViewById(R.id.whell_view);

        rootView.findViewById(R.id.tv_cancel).setOnClickListener(this);
        rootView.findViewById(R.id.tv_confirm).setOnClickListener(this);

        setContentView(rootView);

        Window dialogWindow = getWindow();
        dialogWindow.setGravity(Gravity.LEFT | Gravity.BOTTOM);
        WindowManager.LayoutParams lp = dialogWindow.getAttributes();
        lp.x = 0;
        lp.y = 0;
        dialogWindow.setAttributes(lp);
    }


    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.tv_cancel) {
            dismiss();
        } else if (v.getId() == R.id.tv_confirm) {
            dismiss();
            int curIndex = whellView.getCurIndex();
            if (observableEmitter != null && mDatas != null && curIndex < mDatas.size()) {
                Object o = mDatas.get(curIndex);
                observableEmitter.onNext(o);
            }
        }
    }

    public <M> Observable<M> show(List<M> data) {
        mDatas = data;
        whellView.setDataList(mDatas);
        show();

        observable = Observable.create(new ObservableOnSubscribe<M>() {
            @Override
            public void subscribe(ObservableEmitter<M> e) throws Exception {
                observableEmitter = e;
            }
        });

        return observable;
    }
}

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#e6e6e6" />

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dp45"
        android:background="@color/white"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tv_cancel"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:paddingLeft="15dp"
            android:paddingRight="15dp"
            android:text="取消"
            android:textColor="@color/orange_ff3a00"
            android:textSize="16sp" />

        <View
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1" />

        <TextView
            android:id="@+id/tv_confirm"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:paddingLeft="15dp"
            android:paddingRight="15dp"
            android:text="确定"
            android:textColor="@color/orange_ff3a00"
            android:textSize="16sp" />

    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#e6e6e6" />

    <LinearLayout
        android:id="@+id/ll_vessel"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@color/white"
        android:orientation="horizontal">

        <com.xyj.dyd.view.whell.EasyPickerView
            xmlns:custom="http://schemas.android.com/apk/res-auto"
            android:id="@+id/whell_view"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            custom:epvMaxShowNum="3"
            custom:epvRecycleMode="false"
            custom:epvTextColor="#666666"
            custom:epvTextMaxScale="1.05"
            custom:epvTextMinAlpha="0.4"
            custom:epvTextPadding="25dp"
            custom:epvTextSize="13sp" />

    </LinearLayout>

</LinearLayout>

调用时的代码

        List<String> list = new ArrayList<>();

        for (int i = 0; i < 50; i++) {
            list.add(i + "");
        }

        MyWhellView whellView = new MyWhellView(getActivity());
        whellView.show(list).subscribe(new Consumer<String>() {
            @Override
            public void accept(String s) throws Exception {
                Logger.d(s);
            }
        });

经过这样封装后，这个滚轮控件可以适用于所有的数据源，并且new 一个对象后可以多个数据源共用，是不是很方便呢~