我們在生活中總會用到一些東西，有一個東西來管理的 那就是開關

下面我們就寫一個自定義view繪製的開關了

下面就直接上程式碼了

public class KaiGuan extends View {


    boolean flag=true;
    private final Paint paint;

    public interface KaiGuanJieKou{
        void kai();
        void guan();
    }
    KaiGuanJieKou kaiGuanJieKou;

    public void setKaiGuanJieKou(KaiGuanJieKou kaiGuanJieKou) {
        this.kaiGuanJieKou = kaiGuanJieKou;
    }

    public KaiGuan(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        paint = new Paint();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        setMeasuredDimension(75,40);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        int measuredWidth = getMeasuredWidth();//當前控制元件的寬度
        int measuredHeight = getMeasuredHeight();//當前控制元件的高度

        paint.setStrokeWidth(1);
        paint.setColor(getResources().getColor(R.color.lvse));
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        paint.setAntiAlias(true);
        //預設背景開關  左邊綠色，右邊白圓
        /**
         * 將開關分為三個部分，兩邊半圓，中間正方形
         */
        int ziwidth = measuredWidth / 3;
        int ziheight = measuredHeight / 2;


        if(flag){
            paint.setColor(getResources().getColor(R.color.qianhuise));
            //最左邊綠色半圓  引數1，確認半圓的大小，，引數2,繪製的起始角度，，引數3，是繪製的總和角度，，引數4，是否包含圓心，引數5，畫筆
            //引數2和引數3，一定要遵循android的y軸的特殊性，以及引數3的正/逆時針的旋轉
            canvas.drawArc(new RectF(0,0,ziwidth*2,measuredHeight),90,180,true,paint);
            //繪製中心的方塊
            canvas.drawRect(ziwidth,0,ziwidth*2,measuredHeight,paint);
            //繪製最右邊的半圓
            canvas.drawArc(new RectF(ziwidth,0,measuredWidth,measuredHeight),90,-180,true,paint);

            //移動器
            paint.setStrokeWidth(1);
            paint.setColor(Color.WHITE);
            paint.setStyle(Paint.Style.FILL_AND_STROKE);
            paint.setAntiAlias(true);
            //左邊魚眼  引數1，圓心的x座標，引數2，圓心的y軸座標，，引數3，圓的半徑
            canvas.drawCircle(ziwidth,ziheight,ziheight-2,paint);
        }else{

            //最左邊綠色半圓  引數1，確認半圓的大小，，引數2,繪製的起始角度，，引數3，是繪製的總和角度，，引數4，是否包含圓心，引數5，畫筆
            //引數2和引數3，一定要遵循android的y軸的特殊性，以及引數3的正/逆時針的旋轉
            canvas.drawArc(new RectF(0,0,ziwidth*2,measuredHeight),90,180,true,paint);
            //繪製中心的方塊
            canvas.drawRect(ziwidth,0,ziwidth*2,measuredHeight,paint);
            //繪製最右邊的半圓
            canvas.drawArc(new RectF(ziwidth,0,measuredWidth,measuredHeight),90,-180,true,paint);

            //移動器  預設在右邊
            paint.setStrokeWidth(1);
            paint.setColor(Color.WHITE);
            paint.setStyle(Paint.Style.FILL_AND_STROKE);
            paint.setAntiAlias(true);
            //右邊魚眼  引數1，圓心的x座標，引數2，圓心的y軸座標，，引數3，圓的半徑
            canvas.drawCircle(ziwidth*2,ziheight,ziheight-2,paint);
        }

    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if(event.getAction()==MotionEvent.ACTION_DOWN){
            int x = (int)event.getX();
            if(x <getMeasuredWidth()/2){
                flag=true;
                kaiGuanJieKou.guan();
            }else{
                flag=false;
                kaiGuanJieKou.kai();
            }
        }
        postInvalidate();
        return true;
    }
}

然後再你用的哪個位置，把這個開關的空間給加進去，給一個id

比如：

然後我們這時候直接給一個id然後調取我們寫的一個自定義介面就可以用了。。