Android自定义RatingBar，评分控件

前言

之前有使用系统的RatingBar，发现不太灵活
于是自己写一个

实现效果

原理

原理图

首先得有两张评星的图，找ui妹子切一下
为了方便定制，我这里写死了宽高 即整个控件的高度就是星星的高度
整体控件宽高按照需求写死
我们还需要几个自定义属性，才能将整个RatingBar绘制出来
padding值 即每个星星之间的距离，我这里五颗星星是居中排版
所以在设置参数时还是需要小小的计算的

每个星星之间的padding值
星星的总颗数
点亮的星星的颗数
点亮星星的样式
默认未点亮星星的样式

res/values/attrs

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!--评星-->
    <declare-styleable name="StarIndicator" >
        <attr name="indicator_icon_chose" format="reference"/>
        <attr name="indicator_icon_normal" format="reference"/>
        <attr name="indicator_margin_left" format="dimension" />
        <attr name="indicator_star_size" format="integer" />
        <attr name="indicator_star_chose" format="integer"/>
    </declare-styleable>
</resources>

这里的margin_left 就是上面的星星之间的距离padding

主程序代码

xml

    <com.chonghao.evaluatestardemo.widget.StarIndicator
        android:id="@+id/star"
        android:layout_width="200dp"  //写死整个View宽度
        android:layout_height="28dp"  //写死整个View高度，也是星星高度
        android:layout_gravity="center_vertical"  
        app:indicator_icon_chose="@mipmap/home_star_pre" //选中星星图片
        app:indicator_icon_normal="@mipmap/home_star_nor" //未选中星星图片
        app:indicator_margin_left="10dp"  //星星间距
        app:indicator_star_chose="5"  //选中星星个数
        app:indicator_star_size="5"/>  //星星总个数

自定义View StarIndicator

package com.chonghao.evaluatestardemo.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

import com.chonghao.evaluatestardemo.R;

import java.util.ArrayList;
import java.util.List;


/**
 * Created by ccb on 2017/8/29.
 * 评分指示器 自定义控件
 */

public class StarIndicator extends View {
    /**
     * 选择的星星 的bitmap
     */
    private Bitmap drawable_chose;
    /**
     * 非选择的星星 的bitmap
     */
    private Bitmap drawable_normal;
    /**
     * 星星总颗数 的bitmap
     */
    private int mStarNumber;
    /**
     * 选择的星星颗数 的bitmap
     */
    private int mChoseNumber;
    /**
     * 邻近星星之间的padding值
     */
    private float mPaddingLeft;
    /**
     * 整个View的高度
     */
    private int mHeight;
    /**
     * 整个View的宽度
     */
    private int mWidth;
    /**
     * 画笔
     */
    private Paint mPaint;
    /**
     * 最左侧星星距离左边界的距离
     */
    private float mLeft0;
    /**
     * 每个星星定位点 点集合
     */
    private List<RectF> mPointList;
    /**
     * 星星点击事件回调
     */
    private StarChoseListener mStarChoseListener;

    public void setStarChoseListener(StarChoseListener starChoseListener) {
        mStarChoseListener = starChoseListener;
    }

    public interface StarChoseListener {
        void choseNumber(int num);
    }

    public StarIndicator(Context context) {
        this(context, null);
    }

    public StarIndicator(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public StarIndicator(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.StarIndicator, defStyleAttr, 0);
        //获取选中图片
        BitmapDrawable drawable = (BitmapDrawable) a.getDrawable(R.styleable.StarIndicator_indicator_icon_chose);
        drawable_chose = drawable.getBitmap();
        //获取选中图片
        BitmapDrawable drawable1 = (BitmapDrawable) a.getDrawable(R.styleable.StarIndicator_indicator_icon_normal);
        drawable_normal = drawable1.getBitmap();
        //获取star个数
        mStarNumber = a.getInteger(R.styleable.StarIndicator_indicator_star_size, 5);
        //选中个数
        mChoseNumber = a.getInteger(R.styleable.StarIndicator_indicator_star_chose, 5);
        //获取 间隙
        mPaddingLeft = a.getDimension(R.styleable.StarIndicator_indicator_margin_left, 5);
        //回收
        a.recycle();
        initPaint();

        Log.d("tag",
                mStarNumber + "mStarNumber" +
                        mChoseNumber + "mChoseNumber" +
                        mPaddingLeft + "mPaddingLeft" +
                        drawable_chose + "drawable_chose" +
                        drawable_normal + "drawable_normal"
        );
    }

    private void initPaint() {
        //获取xml中的属性
        //初始化paint，初始化一些其他内容
        mPaint = new Paint();
        mPaint.setAntiAlias(true);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mHeight = getMeasuredHeight();
        mWidth = getMeasuredWidth();
        Log.d("tag", "mHeight" + mHeight
                + "mWidth" + mWidth
        );
        //测量控件宽高
        //计算文字宽高
        mLeft0 = (mWidth - mStarNumber * mHeight - mPaddingLeft * (mStarNumber - 1)) * 0.5f;
        mPointList = new ArrayList<>();
        for (int i = 0; i < mStarNumber; i++) {
            float left = mLeft0 + i * (mPaddingLeft + mHeight);
            mPointList.add(new RectF(left, 0, left + mHeight, mHeight));
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //画icon
        for (int i = 0; i < mPointList.size(); i++) {
            if (i < mChoseNumber) {
                canvas.drawBitmap(drawable_chose, null, mPointList.get(i), mPaint);
            } else {
                canvas.drawBitmap(drawable_normal, null, mPointList.get(i), mPaint);
            }
        }
    }


    public void setChoseNumber(int choseNumber) {
        mChoseNumber = choseNumber;
        postInvalidate();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                break;
            case MotionEvent.ACTION_MOVE:
            case MotionEvent.ACTION_UP:
                float x = event.getX();
                if (x > mWidth) {
                    x = mWidth;
                }
                if (x < 0) {
                    x = 0;
                }

                int a;
                if (x <= mLeft0) {//最左侧
                    setChoseNumber(a = 0);
                } else if (x >= (mWidth - mLeft0)) {//最右侧  有多少颗 亮多少颗
                    a = mStarNumber;
                    setChoseNumber(mStarNumber);
                } else {
                     a = (int) ((x - mLeft0) / (mHeight + mPaddingLeft) + 1);
                    setChoseNumber(a);
                }
                if (mStarChoseListener != null) {
                    mStarChoseListener.choseNumber(a);
                }
                break;
        }
        return true;
    }
}

MainActivity

      StarIndicator star = (StarIndicator) findViewById(R.id.star);
        star.setChoseNumber(3); //设置选中个数
        //设置监听
        star.setStarChoseListener(new StarIndicator.StarChoseListener() {
            @Override
            public void choseNumber(int num) {
                showToast(num + "");
            }
        });

好了 做起来还是很简单的！