对于自定义view，我是一知半解，正在学习中，将自己实验过的自定义view记录下来，防止自己多次走同样的坑 效果献上一个效果图 自定义view的实现
import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.RectF; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.view.View; /** * Created by wxt on 2017/5/12. */ public class CircleView2 extends View{ private Paint mPaint; private Context mContext; //内圆的半径 private int innerCircle=40; //圆圈的宽度 private int ringWidth=4; //设置圆圈的百分比 private float mPercent; public CircleView2(Context context) { this(context, null); } public CircleView2(Context context, @Nullable AttributeSet attrs) { super(context, attrs); this.mContext = context; mPaint = new Paint(); } @Override protected void onDraw(Canvas canvas) { int center = getWidth() / 2; mPaint.setAntiAlias(true); mPaint.setStyle(Paint.Style.STROKE);//下面修改过paint的style，不在这里设置容易出出现paint的style不管用的情况， innerCircle = dip2px(mContext, 50); ringWidth = dip2px(mContext, 4); mPaint.setARGB(155, 167, 190, 206); mPaint.setStrokeWidth(2);//设置2px的边边 canvas.drawCircle(center, center, innerCircle, mPaint); mPaint.setARGB(255, 212, 225, 233); mPaint.setStrokeWidth(ringWidth);//设置ringWidth宽度的圆环 canvas.drawCircle(center, center, innerCircle + 1 + ringWidth / 2, mPaint); mPaint.setStrokeWidth(2);//设置2px的边边 canvas.drawCircle(center, center, innerCircle + ringWidth + 1, mPaint); RectF rectF = new RectF(); int circleY = (getWidth() - innerCircle * 2 - ringWidth) / 2; rectF.set(circleY, circleY, getWidth() - circleY, getHeight() - circleY); mPaint.setColor(Color.RED); mPaint.setStrokeWidth(ringWidth);//设置ringwidth的宽度的半圆环 canvas.drawArc(rectF, -90, 360 * mPercent, false, mPaint); mPaint.setStyle(Paint.Style.FILL); mPaint.setTextSize(dip2px(getContext(),15)); mPaint.setColor(Color.RED); Paint.FontMetricsInt fontMetricsInt=mPaint.getFontMetricsInt(); canvas.drawText("100%",center-(fontMetricsInt.descent-fontMetricsInt.ascent)/2+fontMetricsInt.ascent/2,center+fontMetricsInt.bottom,mPaint); super.onDraw(canvas); } /** * 根据手机的分辨率从 dp 的单位 转成为 px(像素) */ public static int dip2px(Context context, float dpValue) { final float scale = context.getResources().getDisplayMetrics().density; return (int) (dpValue * scale + 0.5f); } public void setmPercent(float mPercent ) { this.mPercent = mPercent; invalidate(); } }