一个刻度盘的demo

gistfile1.java

package z.hol.viewtest.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

/**
 * 刻度view
 * Created by holmes on 9/10/14.
 */
public class DialProgressView extends View{


    private Rect mDialDect = new Rect();
    private int mRadius;
    private float nickAngle;
    private Point mCentre = new Point();
    private int mDialLength;
    private Paint mPaint;
    private float mDialAngleOffset;

    public DialProgressView(Context context) {
        super(context);
        init(context, null);
    }

    public DialProgressView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public DialProgressView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs){
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

        int width = 400;
        int height = 350;
        mDialLength = 20;

        mDialDect.set(100, 100, 100 + width, 100 + height);
        mRadius = width >> 1;

        mCentre.x = (mDialDect.width() >> 1) + mDialDect.left;
        mCentre.y = (mDialDect.height() >> 1) + mDialDect.top;

        computeNickAngle();

    }

    private void computeNickAngle(){

        float remin = 270.0f;

        mDialAngleOffset = remin / (float) 100;


    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        drawDial(canvas);
    }

    private void drawDial(Canvas canvas){
        canvas.save();

        float offset = 180.0f - 90.0f / 2;
        canvas.rotate(-offset, mCentre.x, mCentre.y);

        mPaint.setStrokeWidth(2);
        mPaint.setColor(Color.WHITE);

        int currentX = mCentre.x;
        int currentY = mDialDect.top;

        int dx = currentX;
        int dy = currentY + mDialLength;

        for (int i = 0; i < 100; i ++){
            float da = 0.0f;
            if (i > 0){
                da = mDialAngleOffset;
            }
            canvas.rotate(da, mCentre.x, mCentre.y);
            canvas.drawLine(currentX, currentY, dx, dy, mPaint);
        }

        canvas.restore();
    }
}