手動擼個Android雷達圖（蜘蛛網圖）RadarView
阿新 • • 發佈：2018-05-13
startx ech tro eset 部分 starty fill 中心 公司
公司產品需要一個雷達圖來展示各維度的比重，網上找了一波，學到不少，直接自己上手來擼一記
無圖言虛空
簡單分析一波，確定雷達圖正幾邊形的--正五邊形 int count=5，分為幾個層數--4 層 int layerCount=4
@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！
自定義RadarView繼承View
確定需要使用的變量，初始化paint，計算圓心角
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); }
確定中心點
需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，確定半徑
@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;
}
繪制正五邊形
繪制正五邊形同時描繪最外圍的點，確定分為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
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) {
//每一層第一個點坐標
path.moveTo(centerX, centerY - curR);
} else {
//順時針記錄其余頂角的點坐標
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);
}
}
繪制連線
繪制最內層頂角到最外層頂角的連線
private void drawLines(Canvas canvas) {
float r = radius / layerCount;
for (int i = 0; i < count; i++) {
//起始坐標 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);
//末端坐標
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);
}
}
至此簡易雷達圖成型，可以修改正幾邊形，多少層數（後續繼續添加文字）
//設置幾邊形，**註意：設置幾邊形需要重新計算圓心角**
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);
對於以下圖形的，可以設置第一個點坐標位於中心點正右側(centerX+curR,centerY)，順時針計算其余頂點坐標x = (float) (centerX+curR*Math.cos(angle*j)), y = (float) (centerY+curR*Math.sin(angle*j))，同理連線等其余坐標相應改變...
描繪文字
由於各產品維度內容不同，所需雷達圖樣式不一，這裏只是描繪下不同位置的文字處理情況，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坐標
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);
}
}
}
繪制覆蓋區域
繪制覆蓋區域，百分比取連線長度的百分比(如果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);
}
至此，一個簡單的雷達圖完畢。同時歡迎關註微信公眾號
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手動擼個Android雷達圖（蜘蛛網圖）RadarView