Android自定义View画圆功能

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脚本之家。

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