Android studio 继承view 画笔画圆、画方形、画三角形、画扇形、画椭圆

MainActivity

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

自定义代码

Zidingy

public class Zidingy extends View {
    private Paint mPaint;
    Context mContext;

    public Zidingy(Context context) {
        super(context);
    }

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

    public Zidingy(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.mContext=context;
    }
    /*测量*/

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

    @Override
    protected void onDraw(Canvas canvas) {
        /*画图*/
        /*初始化画笔 文字*/
        super.onDraw(canvas);
        Paint pa = new Paint();
        /*圆*/
        int we=canvas.getWidth()/2;
        int he=canvas.getHeight()/2;
        canvas.drawColor(Color.WHITE);
        pa.setColor(Color.RED);
        canvas.drawCircle(we,he,200,pa);
        pa.setColor(Color.WHITE);
        canvas.drawCircle(we,he,150,pa);
        pa.setColor(Color.YELLOW);
        canvas.drawCircle(we,he,100,pa);
        pa.setColor(Color.BLUE);
        canvas.drawText("武晓瑞",we-17,he,pa);

        //-------------------------------------------------------------------
        // 创建画笔(正方形)
        Paint p = new Paint();
        //设置实心
        p.setStyle(Paint.Style.FILL);
        // 设置红色
        p.setColor(Color.BLACK);
        // 设置画笔的锯齿效果
        p.setAntiAlias(true);
        //绘制
//        canvas.drawRect(50, 100, 300, 300, p);//(左、上、右、下)
        canvas.drawRect(10,150,300,300,p);

//        canvas.drawText("我是你的小可爱",wi-40,hi,pa);
        //-------------------------------------------------------------------
        /*三角形*/
        Paint p1 = new Paint();
        p1.setColor(Color.BLACK);
        //实例化路径
        Path path = new Path();
        path.moveTo(80, 200);// 此点为多边形的起点
        path.lineTo(120, 250);
        path.lineTo(80, 250);
        path.close(); // 使这些点构成封闭的多边形
        canvas.drawPath(path, p1);
        //-------------------------------------------------------------------
        /*扇形——SectorActivity*/
        // 创建画笔
        Paint p2 = new Paint();
        p2.setColor(Color.RED);
        RectF rectF = new RectF(60, 100, 200, 240);
        canvas.drawArc(rectF, 200, 130, true, p2);
        //-------------------------------------------------------------------
        /*椭圆——OvalActivity*/
        // 创建画笔
        Paint p3 = new Paint();
        p3.setColor(Color.GREEN);
        RectF rectF1 = new RectF(60, 100, 200, 240);
        rectF1.set(210,100,250,130);
        canvas.drawOval(rectF1, p3);
    }

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

    /*监听事件*/
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return super.onTouchEvent(event);
    }

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

布局代码

xml文件

<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.huayuan.MainActivity">

    <com.bwie.test.huayuan.Zidingy
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
RelativeLayout>

自定义属性（里面参数自行修改）

<resources>
    <declare-styleable name="PercentageRing">
        <attr name="radius" format="integer"/>
        <attr name="circleBackground" format="color"/>
        <attr name="ringColor" format="color"/>
        <attr name="textColor" format = "color"/>

    declare-styleable>
resources>