公司要做一个产品，产品要连接WiFi，我呢，就弄了一个小的自定义View，来显示Wifi的信号强度，上个图，然后把代码贴上来。

Screenshot_20200825_170843_com.example.hytapparat.jpg

package com.example.hytapparatus.views;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.net.wifi.WifiManager;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.Nullable;

public class WiFiStateView extends View {

    private int wifi_state = 3;

    private int height,width;

    private Paint paint;

    private int startAngle,sweepAngle;

    private int wifiHeight = 0;

    private int padding_bottom ;

    private int bottom_x,bottom_y;

    enum Style{
        RECT,ROUND
    }
    private Style style = Style.ROUND;

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

    public WiFiStateView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs,0);
    }

    public WiFiStateView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.BLACK);
        paint.setAntiAlias(true);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //获取宽的测量模式
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);//测量值
        height = resolveSize(heightSize, heightMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);//测量值
        width = resolveSize(widthSize, widthMeasureSpec);

        int calc_wifi_height = (int) (width / (Math.sqrt(2)));
        wifiHeight = Math.min(calc_wifi_height,height);
        padding_bottom = (height - wifiHeight)/2;
        bottom_x = width /2;
        bottom_y = height - padding_bottom;

        setMeasuredDimension(width, height);
    }

    public void setWifi_state(int level) {
        this.wifi_state = WifiManager.calculateSignalLevel(level,5);
        postInvalidate();
    }

    public void setStyle(Style style) {
        this.style = style;
        postInvalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        int signalRadius = wifiHeight / 4;
        int paint_width = signalRadius/2;
        paint.setStrokeWidth(paint_width);
        if(style == Style.RECT){
            paint.setStrokeCap(Paint.Cap.BUTT);
            startAngle = -135;
            sweepAngle = 90;
        }else {
            paint.setStrokeCap(Paint.Cap.ROUND);
            startAngle = -130;
            sweepAngle = 80;
        }
        for(int i = 1;i <= 4; i ++){
            float radius = signalRadius * i;
            if(i<=wifi_state){
                paint.setColor(Color.parseColor("#4b4b4b"));
            }else {
                paint.setColor(Color.parseColor("#c9c9c9"));
            }
            RectF rectf;
            if(i == 1){
                paint.setStyle(Paint.Style.FILL);
                if(style == Style.RECT){
                    rectf = new RectF(bottom_x - radius  ,bottom_y - radius,bottom_x + radius,bottom_y + radius);
                    canvas.drawArc(rectf,startAngle,sweepAngle,true , paint);
                }else {
                    canvas.drawCircle(bottom_x,bottom_y -paint_width,paint_width,paint );
                }

            }else {
                paint.setStyle(Paint.Style.STROKE);
                rectf = new RectF(bottom_x - radius + paint_width/2,bottom_y - radius + paint_width/2,bottom_x + radius -  paint_width/2,bottom_y + radius -  paint_width/2);
                canvas.drawArc(rectf,startAngle,sweepAngle,false , paint);
            }
        }
    }
}