Android怎么自定义View实现风车效果

本篇内容介绍了“Android怎么自定义View实现风车效果”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

效果图：

画杆

publicclassWindmillRodViewextendsView{privateintmWidth;privateintmHeight;privatePaintmPaint;publicWindmillRodView(Contextcontext){this(context,null);}publicWindmillRodView(Contextcontext,AttributeSetattrs){this(context,attrs,0);}publicWindmillRodView(Contextcontext,AttributeSetattrs,intdefStyleAttr){super(context,attrs,defStyleAttr);init();}privatevoidinit(){mPaint=newPaint();mPaint.setColor(Color.WHITE);mPaint.setStyle(Paint.Style.FILL);mPaint.setAntiAlias(true);mPaint.setDither(true);}@OverrideprotectedvoidonSizeChanged(intw,inth,intoldw,intoldh){super.onSizeChanged(w,h,oldw,oldh);mWidth=getMeasuredWidth();mHeight=getMeasuredHeight();}privateint_rod_width=dp2px(2);@OverrideprotectedvoidonDraw(Canvascanvas){intxCenter=mWidth/2;intyCenter=mHeight/3;intradius=mHeight/3*2;drawRod(canvas,xCenter,yCenter,radius);}privatevoiddrawRod(Canvascanvas,intxCenter,intyCenter,intradius){Pathpath=newPath();path.moveTo(xCenter-_rod_width,yCenter);path.lineTo(xCenter-2*_rod_width,radius-dp2px(5));path.lineTo((xCenter+2*_rod_width),radius-dp2px(5));path.lineTo(xCenter+_rod_width,yCenter);path.close();canvas.drawPath(path,mPaint);RectFrectF=newRectF(xCenter-2*_rod_width,radius-dp2px(8),xCenter+2*_rod_width,radius-dp2px(3));canvas.drawOval(rectF,mPaint);}privateintdp2px(intdp){return(int)(Resources.getSystem().getDisplayMetrics().density*dp+0.5);}}

先画风车的杆，再在底部画一个椭圆

画风车

publicclassWindmillViewextendsView{privateintmWidth;privateintmHeight;privatePaintmPaint;privateObjectAnimatormRotationAnim;publicWindmillView(Contextcontext){this(context,null);}publicWindmillView(Contextcontext,AttributeSetattrs){this(context,attrs,0);}publicWindmillView(Contextcontext,AttributeSetattrs,intdefStyleAttr){super(context,attrs,defStyleAttr);init();}privatevoidinit(){mPaint=newPaint();mPaint.setColor(Color.WHITE);mPaint.setStyle(Paint.Style.FILL);mPaint.setAntiAlias(true);mPaint.setDither(true);}@OverrideprotectedvoidonSizeChanged(intw,inth,intoldw,intoldh){super.onSizeChanged(w,h,oldw,oldh);mWidth=getMeasuredWidth();mHeight=getMeasuredHeight();}@OverrideprotectedvoidonDraw(Canvascanvas){intxCenter=mWidth/2;intyCenter=mHeight/3;intradius=mHeight/3*2;canvas.drawCircle(xCenter,yCenter-dp2px(7),dp2px(4),mPaint);setPivotX(xCenter);setPivotY(yCenter-dp2px(7));canvas.save();for(inti=0;i<3;i++){Pathpath=newPath();path.moveTo(xCenter,0);path.lineTo(xCenter,yCenter-dp2px(11));path.lineTo(xCenter+dp2px(8),yCenter-dp2px(26));path.close();//mPaint.setStrokeJoin(Paint.Join.ROUND);CornerPathEffectcornerPathEffect=newCornerPathEffect(30);mPaint.setPathEffect(cornerPathEffect);canvas.drawPath(path,mPaint);canvas.rotate(360/3,xCenter,yCenter-dp2px(7));}canvas.restore();startAnim();}privateintdp2px(intdp){return(int)(Resources.getSystem().getDisplayMetrics().density*dp+0.5);}publicvoidstartAnim(){if(mRotationAnim!=null&&mRotationAnim.isRunning())return;mRotationAnim=ObjectAnimator.ofFloat(this,"Rotation",360f).setDuration(3000);mRotationAnim.setRepeatCount(-1);mRotationAnim.setInterpolator(newLinearInterpolator());mRotationAnim.start();}publicvoidstopAnim(){if(mRotationAnim!=null&&mRotationAnim.isRunning()){mRotationAnim.cancel();mRotationAnim=null;}}}

这里使用画面的旋转方法，绘制扇页

旋转

使用属性动画来旋转

....publicvoidstartAnim(){if(mRotationAnim!=null&&mRotationAnim.isRunning())return;mRotationAnim=ObjectAnimator.ofFloat(this,"Rotation",360f).setDuration(3000);mRotationAnim.setRepeatCount(-1);mRotationAnim.setInterpolator(newLinearInterpolator());mRotationAnim.start();}publicvoidstopAnim(){if(mRotationAnim!=null&&mRotationAnim.isRunning()){mRotationAnim.cancel();mRotationAnim=null;}}....

在布局文件中使用

<?xmlversion="1.0"encoding="utf-8"?><RelativeLayoutxmlns:android="schemas.android/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:background="#000000">&lt.example.windmill.WindmillRodViewandroid:layout_width="200dp"android:layout_height="200dp"android:layout_centerInParent="true"/>&lt.example.windmill.WindmillViewandroid:layout_width="200dp"android:layout_height="200dp"android:layout_centerInParent="true"/></RelativeLayout>

这里只是介绍了如何绘制类似的效果，很多计算都是写死的，如果要实际使用的话，最好写成自定义属性通过xml属性声明传进去。

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