Android自定义View画圆功能

本文实例为大家分享了Android自定义View画圆的具体代码，供大家参考，具体内容如下

引入布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/activity_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:paddingBottom="@dimen/activity_vertical_margin"
 android:paddingLeft="@dimen/activity_horizontal_margin"
 android:paddingRight="@dimen/activity_horizontal_margin"
 android:paddingTop="@dimen/activity_vertical_margin"
 tools:context="com.bwie.test.xuejian1508a20170928.MainActivity"> 

 <com.bwie.test.xuejian1508a20170928.ViView
 android:layout_width="match_parent"
 android:layout_height="match_parent"
  />
</RelativeLayout>

自定义View的java类，继承View

public class ViView extends View{
 Paint paint;
 Context context;
 //构造方法
 public ViView(Context context) {
 super(context);
 } 

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

 public ViView(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 } 

 public ViView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
 super(context, attrs, defStyleAttr, defStyleRes);
 this.context=context;
 } 

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 } 

 @Override
 protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
 super.onLayout(changed, left, top, right, bottom); 

 } 

 /*绘图*/
 @Override
 protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 //得到屏幕宽高
 int width = getWidth();
 int radius = width - 450/2;
 int height = getHeight();
// 创建画笔
 Paint paint1 = new Paint();
 Paint paint2 = new Paint();
 Paint paint3= new Paint();
// 消除锯齿
 paint1.setAntiAlias(true);
 paint2.setAntiAlias(true);
 paint3.setAntiAlias(true);
 //画笔颜色
 paint1.setColor(Color.RED);
 paint2.setColor(Color.WHITE);
 paint3.setColor(Color.BLUE);
// 画圆。确定位置
// canvas.drawRect(100,100,width/2,height/2,paint1);
// canvas.drawCircle(100,100,100,paint1);
// canvas.drawCircle(250,250,200,paint2);
// canvas.drawCircle(500,500,300,paint3);
 //设置圆环形状和大小
 RectF oval = new RectF(width-radius,width-radius,width+radius,width+radius);
 paint1.setStrokeWidth(450);
 canvas.drawArc(oval,-90,90,false,paint1); 

 canvas.drawCircle(width/2,height/2,450,paint1);
 canvas.drawCircle(width/2,height/2,300,paint2);
 canvas.drawCircle(width/2,height/2,200,paint3);
 } 

 @Override
 public boolean onTouchEvent(MotionEvent event) {
 return super.onTouchEvent(event);
 }
}

效果图：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。