自定义控件之仪表盘

先看效果

Paste_Image.png

完整代码如下
整个圆弧280，分为7份，每份角度为40°。

package example.com.dashbarddemo;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.view.View;
public class BoardView extends View {
    private TextPaint textPaint;
    private Paint linePaint;
    private float centerX;
    private float centerY;
    private String[] texts;
    private float radius;
    private Rect rect;
    //大刻度线距离文字的距离
    private float text2line;
    //小刻度线距离文字的距离
    private float text2lineshorter;
    private Paint arcPaint;
    private Paint stripPaint;
    private float angle=0.001f;
    //蓝色弧形的宽度
    private float stripStrokeWidth;
    private Paint mPaint;
    //最外层弧线的宽度
    private float strokWidth;
    private Paint circlePaint;
    private RectF rectF;
    private RectF rectF2;
    private RectF rectF3;
    private RectF rectF4;
    //刻度线宽度
    private float ticksWidth=dp2px(2);
    //刻度线长度
    private float ticksHeight=dp2px(20);
    public float getAngle() {
        return angle;
    }
    public void setAngle(float angle) {
        this.angle = angle;
        invalidate();
    }
    public BoardView(Context context) {
        this(context,null);
    }
    public BoardView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }
    public BoardView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //文字
        textPaint = new TextPaint();
        textPaint.setAntiAlias(true);
        textPaint.setTextSize(20);
        textPaint.setColor(Color.BLACK);
        //刻度线
        linePaint = new Paint();
        linePaint.setAntiAlias(true);
        linePaint.setColor(Color.parseColor("#dedede"));
        linePaint.setStrokeWidth(ticksWidth);
        texts = new String[]{"250","350","450","550","650","750","850","950"};
        //文字的宽高
        rect = new Rect();
        textPaint.getTextBounds(texts[0],0,texts[0].length(), rect);
        text2line = dp2px(10);
        text2lineshorter = dp2px(6);
        //圆环
        arcPaint = new Paint();
        arcPaint.setAntiAlias(true);
        arcPaint.setStyle(Paint.Style.STROKE);
        arcPaint.setStrokeWidth(dp2px(2));
        arcPaint.setColor(Color.BLACK);
        //白条
        stripPaint = new Paint();
        stripPaint.setAntiAlias(true);
        stripPaint.setStyle(Paint.Style.STROKE);
        stripPaint.setColor(Color.WHITE);
        stripStrokeWidth = dp2px(12);
        stripPaint.setStrokeWidth(stripStrokeWidth);
        //最外层圆弧
        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setAntiAlias(true);
        mPaint.setColor(Color.parseColor("#7fffffff"));
        strokWidth = dp2px(3);
        mPaint.setStrokeWidth(strokWidth);
        //光点
        circlePaint = new Paint();
        circlePaint.setAntiAlias(true);
        circlePaint.setColor(Color.WHITE);
        circlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
    }
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        //圆心
        centerX = getMeasuredWidth()/2;
        centerY = getMeasuredHeight()/2;
        //半径
        radius = getMeasuredWidth()/2*0.6f;
        rectF = new RectF();
        rectF.left=-radius-dp2px(21);
        rectF.top=-radius-dp2px(21);
        rectF.right=radius+dp2px(21);
        rectF.bottom=radius+dp2px(21);
        rectF2 = new RectF();
        rectF2.left=-radius-dp2px(35);
        rectF2.top=-radius-dp2px(35); 
       rectF2.right=radius+dp2px(35);
       rectF2.bottom=radius+dp2px(35);
        rectF3 = new RectF();
        rectF3.left=-radius-dp2px(22)-stripStrokeWidth/2;
        rectF3.top=-radius-dp2px(22)-stripStrokeWidth/2;
        rectF3.right=radius+dp2px(22)+stripStrokeWidth/2;
        rectF3.bottom=radius+dp2px(22)+stripStrokeWidth/2;
        rectF4 = new RectF();
        rectF4.left=-radius-dp2px(45)-strokWidth/2;
        rectF4.top=-radius-dp2px(45)-strokWidth/2;
        rectF4.right=radius+dp2px(45)+strokWidth/2;
        rectF4.bottom=radius+dp2px(45)+strokWidth/2;
    }
    @Override    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save();
        canvas.translate(centerX,centerY);
        //绘制文字
        for(int i=0;i<texts.length;i++){
            canvas.save();
            canvas.rotate(-140+40*i);
            canvas.drawText(texts[i],0-rect.width()/2,-radius,textPaint);
            canvas.restore();
        }
        //绘制刻度线
        for(int i=0;i<36;i++){
            canvas.save();
            canvas.rotate(-140+i*8);
            if(i%5==0){
                canvas.drawLine(0,-radius-dp2px(20),0,-radius-dp2px(20)+text2line,linePaint);
            }else{
                canvas.drawLine(0,-radius-dp2px(20),0,-radius-dp2px(20)+text2lineshorter,linePaint);
            }
            canvas.restore();
        }
        //刻度线所在内圆环
        canvas.drawArc(rectF,130,280,false,arcPaint);
        //刻度线所在外圆环
        canvas.drawArc(rectF2,130,280,false,arcPaint);
        //闭合圆环
        canvas.save();
        canvas.rotate(-140);
        canvas.drawLine(0,-radius-dp2px(20),0,-radius-dp2px(36),arcPaint);
        canvas.rotate(280);
        canvas.drawLine(0,-radius-dp2px(20),0,-radius-dp2px(36),arcPaint);
        canvas.restore();
        //白条
        canvas.drawArc(rectF3,130,angle,false,stripPaint);
        //弧线 
       canvas.drawArc(rectF4,130,angle,false,mPaint);
        //光点
        canvas.save();
        canvas.rotate(angle);
        float distance=radius+dp2px(45)+strokWidth/2;
        canvas.drawCircle((float) (-distance*Math.sin(Math.toRadians(40))),(float)(distance*Math.cos(Math.toRadians(40))),dp2px(3),circlePaint);
        canvas.restore();
        canvas.restore();
    }
    private float dp2px(float dp){
        return getContext().getResources().getDisplayMetrics().density*dp+0.5f;
    }
}

部分解说
文字绘制部分

Paste_Image.png

//绘制文字
for(int i=0;i<texts.length;i++){
    canvas.save();
    canvas.rotate(-140+40*i);
    canvas.drawText(texts[i],0-rect.width()/2,-radius,textPaint);
    canvas.restore();
}