手動擼個Android雷達圖（蜘蛛網圖）RadarView

時間  2019-12-05
標籤 手動 android 雷達圖 蜘蛛網 radarview 欄目 Android 简体版
原文   原文鏈接
原文連接 https://mp.weixin.qq.com/s/Ms...

公司產品須要一個雷達圖來展現各維度的比重，網上找了一波，學到很多，直接本身上手來擼一記canvas

無圖言虛空微信

image

簡單分析一波，肯定雷達圖正幾邊形的--正五邊形 int count=5，分爲幾個層數--4 層 int layerCount=4ide

    @Override

    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        drawPolygon(canvas);//畫邊
        drawLines(canvas);//畫線
        drawText(canvas);//描繪文字
        drawRegion(canvas);//覆蓋區域
    }

主要這幾步，開擼！this

自定義RadarView繼承View

肯定須要使用的變量，初始化paint，計算圓心角spa

private int count = 5; //幾邊形    
private int layerCount = 4; //層數    
privatefloatangle; //每條邊對應的圓心角   
private int centerX; //圓心x    
private int centerY; //圓心y    
privatefloatradius; //半徑    
private Paint polygonPaint; //邊框paint    
private Paint linePaint; //連線paint    
private Paint txtPaint; //文字paint    
private Paint circlePaint; //圓點paint    
private Paint regionColorPaint; //覆蓋區域paint    
private Double[] percents = {0.91, 0.35, 0.12, 0.8, 0.5}; //覆蓋區域百分比    
private String[] titles = {"dota","鬥地主","大吉大利，晚上吃雞","爐石傳說","跳一跳"};//文字
public RadarView(Context context) {
        this(context, null, 0);
    }

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

    public RadarView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //計算圓心角
        angle = (float) (Math.PI * 2 / count);

        polygonPaint = new Paint();
        polygonPaint.setColor(ContextCompat.getColor(context, R.color.radarPolygonColor));
        polygonPaint.setAntiAlias(true);
        polygonPaint.setStyle(Paint.Style.STROKE);
        polygonPaint.setStrokeWidth(4f);

        linePaint = new Paint();
        linePaint.setColor(ContextCompat.getColor(context, R.color.radarLineColor));
        linePaint.setAntiAlias(true);
        linePaint.setStyle(Paint.Style.STROKE);
        linePaint.setStrokeWidth(2f);

        txtPaint = new Paint();
        txtPaint.setColor(ContextCompat.getColor(context, R.color.radarTxtColor));
        txtPaint.setAntiAlias(true);
        txtPaint.setStyle(Paint.Style.STROKE);
        txtPaint.setTextSize(DensityUtil.dpToPx(context, 12));

        circlePaint = new Paint();
        circlePaint.setColor(ContextCompat.getColor(context, R.color.radarCircleColor));
        circlePaint.setAntiAlias(true);

        regionColorPaint = new Paint();
        regionColorPaint.setColor(ContextCompat.getColor(context, R.color.radarRegionColor));
        regionColorPaint.setStyle(Paint.Style.FILL);
        regionColorPaint.setAntiAlias(true);

    }

肯定中心點

須要正五邊形得有一個圓，圓內接正五邊形，在onSizeChanged方法裏獲取圓心，肯定半徑code

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        radius = Math.min(h, w) / 2 * 0.7f;
        centerX = w / 2;
        centerY = h / 2;
    }blog

繪製正五邊形

繪製正五邊形同時描繪最外圍的點，肯定分爲4層，半徑 / 層數 =每層之間的間距，從最裏層開始畫正五邊形，每層第一個點位於中心點正上方繼承

private void drawPolygon(Canvas canvas) {
        Path path = new Path();
        float r = radius / layerCount;
        for (int i = 1; i <= layerCount; i++) {
            float curR = r * i; //當前所在層的半徑
            for (int j = 0; j < count; j++) {
                if (j == 0) {
                    //每一層第一個點座標
                    path.moveTo(centerX, centerY - curR);  
                } else {
                    //順時針記錄其他頂角的點座標
                    float x = (float) (centerX + Math.sin(angle * j) * curR);
                    float y = (float) (centerY - Math.cos(angle * j) * curR);
                    path.lineTo(x, y);
                }
            }
            //最外層的頂角外面的五個小圓點(圖中紅色部分)
            if (i == layerCount) {
                for (int j = 0; j < count; j++) {
                    float x = (float) (centerX + Math.sin(angle * j) * (curR + 12));
                    float y = (float) (centerY - Math.cos(angle * j) * (curR + 12));
                    canvas.drawCircle(x, y, 4, circlePaint);
                }
            }
            path.close();
            canvas.drawPath(path, polygonPaint);
        }
    }

image.png

繪製連線

繪製最內層頂角到最外層頂角的連線ci

private void drawLines(Canvas canvas) {
        float r = radius / layerCount;
        for (int i = 0; i < count; i++) {
            //起始座標 從中心開始的話 startx=centerX , startY=centerY
            float startX = (float) (centerX + Math.sin(angle * i) * r);
            float startY = (float) (centerY - Math.cos(angle * i) * r);
            //末端座標
            float endX = (float) (centerX + Math.sin(angle * i) * radius);
            float endY = (float) (centerY - Math.cos(angle * i) * radius);
            canvas.drawLine(startX, startY, endX, endY, linePaint);
        }
    }

image.png
至此簡易雷達圖成型，能夠修改正幾邊形，多少層數（後續繼續添加文字）rem

//設置幾邊形，**注意：設置幾邊形須要從新計算圓心角**
    public void setCount(int count){
        this.count = count;
        angle = (float) (Math.PI * 2 / count);
        invalidate();
    }

    //設置層數
    public void setLayerCount(int layerCount){
        this.layerCount = layerCount;
        invalidate();
    }

設置正六邊形、六層

    radarView.setCount(6);
    radarView.setLayerCount(6);

image.png

對於如下圖形的，能夠設置第一個點座標位於中心點正右側(centerX+curR,centerY)，順時針計算其他頂點座標x = (float) (centerX+curR*Math.cos(angle*j)), y = (float) (centerY+curR*Math.sin(angle*j))，同理連線等其他座標相應改變...
image.png

描繪文字

因爲各產品維度內容不一樣，所需雷達圖樣式不一，這裏只是描繪下不一樣位置的文字處理狀況，具體需求還得按產品來，因產品而異

private void drawText(Canvas canvas) {
        for (int i = 0; i < count; i++) {
            //獲取到雷達圖最外邊的座標
            float x = (float) (centerX + Math.sin(angle * i) * (radius + 12));
            float y = (float) (centerY - Math.cos(angle * i) * (radius + 12));
            if (angle * i == 0) {
                //第一個文字位於頂角正上方
                txtPaint.setTextAlign(Paint.Align.CENTER);
                canvas.drawText(titles[i], x, y - 18, txtPaint);
                txtPaint.setTextAlign(Paint.Align.LEFT);
            } else if (angle * i > 0 && angle * i < Math.PI / 2) {
                //微調
                canvas.drawText(titles[i], x + 18, y + 10, txtPaint);
            } else if (angle * i >= Math.PI / 2 && angle * i < Math.PI) {
                //最右下的文字獲取到文字的長、寬，按文字長度百分比向左移
                String txt = titles[i];
                Rect bounds = new Rect();
                txtPaint.getTextBounds(txt, 0, txt.length(), bounds);
                float height = bounds.bottom - bounds.top;
                float width = txtPaint.measureText(txt);
                canvas.drawText(txt, x - width * 0.4f, y + height + 18, txtPaint);
            } else if (angle * i >= Math.PI && angle * i < 3 * Math.PI / 2) {
                //同理最左下的文字獲取到文字的長、寬，按文字長度百分比向左移
                String txt = titles[i];
                Rect bounds = new Rect();
                txtPaint.getTextBounds(txt, 0, txt.length(), bounds);
                float width = txtPaint.measureText(txt);
                float height = bounds.bottom - bounds.top;
                canvas.drawText(txt, x - width * 0.6f, y + height + 18, txtPaint);
            } else if (angle * i >= 3 * Math.PI / 2 && angle * i < 2 * Math.PI) {
                //文字向左移動
                String txt = titles[i];
                float width = txtPaint.measureText(txt);
                canvas.drawText(txt, x - width - 18, y + 10, txtPaint);
            }

        }
    }

image.png

繪製覆蓋區域

繪製覆蓋區域，百分比取連線長度的百分比(若是從中心點開始的連線，則是半徑的百分比)，此處用半徑radius減去間隔r即連線長度

private void drawRegion(Canvas canvas) {
        Path path = new Path();
        float r = radius / layerCount;//每層的間距
        for (int i = 0; i < count; i++) {
            if (i == 0) {
                path.moveTo(centerX, (float) (centerY - r - (radius - r) * percents[i]));
            } else {
                float x = (float) (centerX + Math.sin(angle * i) * (percents[i] * (radius - r) + r));
                float y = (float) (centerY - Math.cos(angle * i) * (percents[i] * (radius - r) + r));
                path.lineTo(x, y);
            }
        }
        path.close();
        canvas.drawPath(path, regionColorPaint);
    }

image.png

至此，一個簡單的雷達圖完畢。
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