静态波形绘制

Posted 2021-01-05 lucky-zhu

背景，需要弄个波形顶部的背景，所以就网上找了个demo来修改所得（技术有限，本人热衷修改（-_-!!））

效果图：

 

以下为自定义View类没什么好讲的：

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

import java.util.Random;


public class WaveView extends View {

    private Paint mPaint;
    private Path mPath;
    private int mWaveLength = 780;
    private int dx=0;
    private int dy;
    private int width;

    public WaveView(Context context) {
        super(context);
        init();
    }

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (width == 0) {
            width = getMeasuredWidth();
        }
    }

    private void init() {
        mPaint = new Paint();
        mPaint.setColor(0x6fF2F2F2);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setAntiAlias(true);
        mPath = new Path();

    }

    int s = 0;

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mPath.reset();
        //一个周期宽度
        mWaveLength = width - 300;
        int originY = 60;
        int mWaveHalfLength = mWaveLength / 2;
        mPath.moveTo(-(mWaveLength * 3 / 4) + 150, originY);
        //波的幅度
        int max = 70;
        int min = 70;
        Random random = new Random();
        s = random.nextInt(max) % (max - min + 1) + min;
//        mWaveLength = random.nextInt(maxW) % (maxW - minW + 1) + minW;
        mPaint.setColor(0xffF2F2F2);//从不同的起点绘制第一条波
        draw(canvas, mWaveHalfLength);
         originY = 80;
        mPaint.setColor(0x4fF2F2F2);
        mPath.moveTo(-0, originY);//从不同的起点绘制第二条波
        draw(canvas, mWaveHalfLength);
        mPath.moveTo(-200, originY);//从不同的起点绘制第三条波
        draw(canvas, mWaveHalfLength);
    }

    private void draw(Canvas canvas, int mWaveHalfLength) {
        //屏幕的宽度里面放多少个波长
        for (int i = -mWaveLength; i < getWidth() + mWaveLength; i += mWaveLength) {
            //相对绘制二阶贝塞尔曲线(相对于自己的起始点--也即是上一个曲线的终点  的距离dx1)
            mPath.rQuadTo(mWaveHalfLength / 2, -s, mWaveHalfLength, 0);
            mPath.rQuadTo(mWaveHalfLength / 2, s, mWaveHalfLength, 0);
        }
        //颜色填充
        //画一个封闭的空间
        mPath.lineTo(getWidth(), getHeight());
        mPath.lineTo(0, getHeight());
        mPath.close();
        canvas.drawPath(mPath, mPaint);
    }
}