自定义view圆形之生成随机数改变

最新推荐文章于 2021-05-26 08:44:20 发布

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最新推荐文章于 2021-05-26 08:44:20 发布

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本文链接：https://blog.youkuaiyun.com/qq_38759627/article/details/74635434

本文介绍了一个自定义Android视图的实现案例，通过该视图可以绘制带有随机数显示的圆环，并实现了触摸响应功能。代码展示了如何使用Canvas进行图形绘制，包括设置颜色、样式及抗锯齿等。

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import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import java.util.Random;


public class MyView extends View{
    private final Paint paint;
    private final Context context;
    private int i=1234;

    public MyView(Context context) {
        this(context,null);
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        this.paint = new Paint();
        this.paint.setAntiAlias(true); //消除锯齿
        this.paint.setStyle(Paint.Style.STROKE); //绘制空心圆
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        int center = getWidth()/2;
        int innerCircle = dip2px(context, 83); //设置内圆半径
        int ringWidth = dip2px(context, 5); //设置圆环宽度

        //绘制内圆
        this.paint.setARGB(155, 167, 190, 206);
        this.paint.setStrokeWidth(100);
        this.paint.setColor(Color.YELLOW);
        canvas.drawCircle(center,center, innerCircle, this.paint);


        //绘制文字
        Paint  textPaint = new Paint();
        textPaint.setColor(Color.BLACK);
        textPaint.setStyle(Paint.Style.FILL);
        textPaint.setTextSize(25);
        canvas.drawText(String.valueOf(i),200,245,textPaint);

//        //绘制圆环
//        this.paint.setARGB(255, 212 ,225, 233);
//        this.paint.setStrokeWidth(50);
//        this.paint.setColor(Color.BLUE);
//        canvas.drawCircle(center,center, innerCircle+1+ringWidth/2, this.paint);

        //绘制外圆
        this.paint.setARGB(155, 167, 190, 206);
        this.paint.setStrokeWidth(80);
        this.paint.setColor(Color.RED);
        canvas.drawCircle(center,center, innerCircle+ringWidth, this.paint);


        super.onDraw(canvas);
    }


    /**
     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
     */
    public static int dip2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                 //随机数的工具
              Random   random = new Random();
             //做计算
            i=1001+(int)(Math.random()*1000);
//                count++;
                invalidate();
                break;
        }
        return super.onTouchEvent(event);
    }
}