自定义控件 - 评价选星

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评价功能一般在B2C开发中期经常见到,故此做一记录,方便日后使用 ~

实现效果

在这里插入图片描述

准备部分
  • res - values - attrs 添加自定义控件的自定义属性
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!--带点击事件的评分控件-->
    <declare-styleable name="StarBar">
        <!--未选中-->
        <attr name="starEmptyRes" format="reference"/>
        <!--选中半个-->
        <attr name="starHalfRes" format="reference"/>
        <!--选中全部-->
        <attr name="starSelectedRes" format="reference"/>
        <!--星星的总数-->
        <attr name="startTotalNumber" format="integer"/>
        <!--默认选中的数量 -->
        <attr name="selectedNumber" format="float"/>
        <!--星星的间距-->
        <attr name="starDistances" format="dimension"/>
        <!--星星的宽度-->
        <attr name="starWidth" format="dimension"/>
        <!--星星的高度-->
        <attr name="starHeight" format="dimension"/>
        <!--是不是只画整个星星,不画半个-->
        <attr name="starIsFull" format="boolean"/>
        <attr name="isCanTouch" format="boolean"/>
    </declare-styleable>
</resources>

准备空星与实星的图片(简而言之,就是未选取状态与选取状态)

  • 未选取状态
    在这里插入图片描述
  • 选取状态
    在这里插入图片描述

核心部分

StarBar 自定义控件(可完全copy)

package com.advance.yongliu.commentstar;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

/**
 * 星星点灯 照亮我的前程
 * 用一点光 温暖孩子的心
 * @author  起源网上 RatingBar
 * */
public class StarBar extends View {
    // 正常、半个和选中的星星
    private Bitmap mStarNormal, mStarHalf, mStarSelected;
    //星星的总数
    private int mStartTotalNumber = 5;
    //选中的星星个数
    private float mSelectedNumber;
    // 星星之间的间距
    private int mStartDistance;
    // 是否画满
    private Status mStatus = Status.FULL;
    // 星星的宽高
    private float mStarWidth;
    private float mStarHeight;
    // 星星选择变化的回调
    private OnStarChangeListener mOnStarChangeListener;
    // 是不是要画满,默认不画半个的
    private boolean isFull;
    // 画笔
    private Paint mPaint = new Paint();
    // 用于判断是绘制半个,还是全部
    private boolean isCanTouch;

    private enum Status {
        FULL, HALF
    }

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

    public StarBar(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public StarBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.RatingBar);

        // 未选中的图片资源
        int starNormalId = array.getResourceId(R.styleable.RatingBar_starEmptyRes, 0);
        if (starNormalId == 0) {
            throw new IllegalArgumentException("请设置属性 starNormal");
        }
        mStarNormal = BitmapFactory.decodeResource(getResources(), starNormalId);
        // 选中一半的图片资源
        int starHalfId = array.getResourceId(R.styleable.RatingBar_starHalfRes, 0);
        if (starHalfId != 0) {
            mStarHalf = BitmapFactory.decodeResource(getResources(), starHalfId);
        }
        // 选中全部的图片资源
        int starSelectedId = array.getResourceId(R.styleable.RatingBar_starSelectedRes, 0);
        if (starSelectedId == 0) {
            throw new IllegalArgumentException("请设置属性 starSelected");
        }
        mStarSelected = BitmapFactory.decodeResource(getResources(), starSelectedId);
        // 如果没设置一半的图片资源,就用全部的代替
        if (starHalfId == 0) {
            mStarHalf = mStarSelected;
        }

        mStartTotalNumber = array.getInt(R.styleable.RatingBar_startTotalNumber, mStartTotalNumber);
        mSelectedNumber = array.getFloat(R.styleable.RatingBar_selectedNumber, mSelectedNumber);
        mStartDistance = (int) array.getDimension(R.styleable.RatingBar_starDistances, 0);
        mStarWidth = array.getDimension(R.styleable.RatingBar_starWidth, 0);
        mStarHeight = array.getDimension(R.styleable.RatingBar_starHeight, 0);
        isFull = array.getBoolean(R.styleable.RatingBar_starIsFull, true);
        isCanTouch = array.getBoolean(R.styleable.RatingBar_isCanTouch, true);
        array.recycle();

        // 如有指定宽高,获取最大值 去改变星星的大小(星星是正方形)
        int starWidth = (int) Math.max(mStarWidth, mStarHeight);
        if (starWidth > 0) {
            mStarNormal = resetBitmap(mStarNormal, starWidth);
            mStarSelected = resetBitmap(mStarSelected, starWidth);
            mStarHalf = resetBitmap(mStarHalf, starWidth);
        }

        // 计算一半还是全部(小数部分小于等于0.5就只是显示一半)
        if (!isFull) {
            int num = (int) mSelectedNumber;
            if (mSelectedNumber <= (num + 0.5f)) {
                mStatus = Status.HALF;
            }
        }
    }

    /**
     * 如果用户设置了图片的宽高,就重新设置图片
     */
    public Bitmap resetBitmap(Bitmap bitMap, int startWidth) {
        // 得到新的图片
        return Bitmap.createScaledBitmap(bitMap, startWidth, startWidth, true);
    }

    /**
     * 设置选中星星的数量
     */
    public void setSelectedNumber(int selectedNumber) {
        if (selectedNumber >= 0 && selectedNumber <= mStartTotalNumber) {
            this.mSelectedNumber = selectedNumber;
            invalidate();
        }
    }

    /**
     * 设置星星的总数量
     */
    public void setStartTotalNumber(int startTotalNumber) {
        if (startTotalNumber > 0) {
            this.mStartTotalNumber = startTotalNumber;
            invalidate();
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        // 用正常的一个星星图片去测量高
        int height = getPaddingTop() + getPaddingBottom() + mStarNormal.getHeight();
        // 宽 = 星星的宽度*总数 + 星星的间距*(总数-1) +padding
        int width = getPaddingLeft() + getPaddingRight() + mStarNormal.getWidth() * mStartTotalNumber + mStartDistance * (mStartTotalNumber - 1);
        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // 循环绘制
        for (int i = 0; i < mStartTotalNumber; i++) {
            float left = getPaddingLeft();
            // 从第二个星星开始,给它设置星星的间距
            if (i > 0) {
                left = getPaddingLeft() + i * (mStarNormal.getWidth() + mStartDistance);
            }
            float top = getPaddingTop();
            // 绘制选中的星星
            if (i < mSelectedNumber) {
                // 比当前选中的数量小
                if (i < mSelectedNumber - 1) {
                    canvas.drawBitmap(mStarSelected, left, top, mPaint);
                } else {
                    // 在这里判断是不是要绘制满的
                    if (mStatus == Status.FULL) {
                        canvas.drawBitmap(mStarSelected, left, top, mPaint);
                    } else {
                        canvas.drawBitmap(mStarHalf, left, top, mPaint);
                    }
                }
            } else {
                // 绘制正常的星星
                canvas.drawBitmap(mStarNormal, left, top, mPaint);
            }

        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            //减少绘制
            case MotionEvent.ACTION_DOWN:
            case MotionEvent.ACTION_MOVE:
                if (isCanTouch) {
                    // 获取用户触摸的x位置
                    float x = event.getX();
                    // 一个星星占的宽度
                    int startWidth = getWidth() / mStartTotalNumber;
                    // 计算用户触摸星星的位置
                    int position = (int) (x / startWidth + 1);
                    if (position < 0) {
                        position = 0;
                    }
                    if (position > mStartTotalNumber) {
                        position = mStartTotalNumber;
                    }
                    // 计算绘制的星星是不是满的
                    float result = x - startWidth * (position - 1);
                    Status status;
                    // 结果大于一半就是满的
                    if (result > startWidth * 0.5f) {
                        // 满的
                        status = Status.FULL;
                    } else {
                        // 一半的
                        status = Status.HALF;
                    }
                    if (isFull) {
                        status = Status.FULL;
                    }
                    //减少绘制
                    if (mSelectedNumber != position || status != mStatus) {
                        mSelectedNumber = position;
                        mStatus = status;
                        invalidate();
                        if (mOnStarChangeListener != null) {
                            position = (int) (mSelectedNumber - 1);
                            // 选中的数量:满的就回调(1.0这种),一半就(0.5这种)
                            float selectedNumber = status == Status.FULL ? mSelectedNumber
                                    : (mSelectedNumber - 0.5f);
                            mOnStarChangeListener.OnStarChanged(selectedNumber,
                                    position < 0 ? 0 : position);
                        }
                    }
                }
                break;
            default:
                break;
        }
        return true;
    }

    //  回调监听(选中的数量,位置)
    public interface OnStarChangeListener {
        void OnStarChanged(float selectedNumber, int position);
    }

    public void setListener(OnStarChangeListener listener) {
        this.mOnStarChangeListener = listener;
    }
}

使用部分

MainActivity

package com.advance.yongliu.commentstar;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView mEvaluate;

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

        mEvaluate = findViewById(R.id.tv_evaluate);
        mEvaluate.setText("暂无评价");
        
        StarBar starDis=findViewById(R.id.rb_quality);

        starDis.setListener(new StarBar.OnStarChangeListener() {
            @Override
            public void OnStarChanged(float selectedNumber, int position) {
                int starNum =(int)selectedNumber;
                mEvaluate.setText(showEvaluateStr(starNum));
            }
        });
    }
    
    //对应星级显示的评分信息
    private String showEvaluateStr(int score)
    {
        String result;
        switch (score)
        {
            case 0:
                result="";
                break;
            case 1:
                result="非常差";
                break;
            case 2:
                result="差";
                break;
            case 3:
                result="一般";
                break;
            case 4:
                result="满意";
                break;
            case 5:
                result="超赞";
                break;
            default:
                result="";
                break;
        }
        return result;
    }
}

activity_main

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

    <TextView
        android:layout_marginTop="20dp"
        android:id="@+id/tv_evaluate"
        android:layout_width="match_parent"
        android:textSize="16sp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="13dp"
        />

    <com.advance.yongliu.commentstar.StarBar
        android:layout_marginTop="10dp"
        android:id="@+id/rb_quality"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="12dp"
        app:selectedNumber="0"
        app:starDistances="12dp"
        app:starEmptyRes="@mipmap/ic_sm_empty_star"
        app:starHeight="22dp"
        app:starIsFull="true"
        app:starSelectedRes="@mipmap/ic_sm_fill_star"
        app:starWidth="22dp"
        app:startTotalNumber="5"/>
</LinearLayout>