Android开发--自定义时频域折线绘制图

直接上干货！！！

1.XML

2.测试函数

    public void generateData(View view) {
        // 生成随机数据
        float timeDomainData = (float) Math.random();
        float frequencyDomainData = (float) Math.random();

        // 更新视图
        customView.setTimeDomainData(timeDomainData);
        customView.setFrequencyDomainData(frequencyDomainData);
    }

3.CustomView实现

public class CustomView extends View {
    private Paint timeDomainPaint;
    private Paint frequencyDomainPaint;
    private Paint axisPaint; // 坐标轴画笔
    private Paint textPaint; // 文本画笔
    private LinkedList timeDomainDataList;
    private LinkedList frequencyDomainDataList;
    private int maxDataCount;
    private float minValue;
    private float maxValue;

    public CustomView(Context context, AttributeSet attrs) {
        super(context, attrs);
        timeDomainPaint = new Paint();
        timeDomainPaint.setColor(Color.BLUE);
        timeDomainPaint.setStrokeWidth(2f);
        timeDomainPaint.setAntiAlias(true);

        frequencyDomainPaint = new Paint();
        frequencyDomainPaint.setColor(Color.RED);
        frequencyDomainPaint.setStrokeWidth(2f);
        frequencyDomainPaint.setAntiAlias(true);

        axisPaint = new Paint();
        axisPaint.setColor(Color.WHITE);
        axisPaint.setStrokeWidth(2f);
        axisPaint.setAntiAlias(true);

        textPaint = new Paint();
        textPaint.setColor(Color.WHITE);
        textPaint.setTextSize(24f);
        textPaint.setAntiAlias(true);

        maxDataCount = 100;
        timeDomainDataList = new LinkedList<>();
        frequencyDomainDataList = new LinkedList<>();
    }

    public void setTimeDomainData(float data) {
        if (timeDomainDataList.size() >= maxDataCount) {
            timeDomainDataList.removeFirst();
        }
        timeDomainDataList.addLast(data);
        updateMinMaxValue();
        invalidate();
    }

    public void setFrequencyDomainData(float data) {
        if (frequencyDomainDataList.size() >= maxDataCount) {
            frequencyDomainDataList.removeFirst();
        }
        frequencyDomainDataList.addLast(data);
        updateMinMaxValue();
        invalidate();
    }

    private void updateMinMaxValue() {
        minValue = Float.MAX_VALUE;
        maxValue = -Float.MAX_VALUE;
        for (float value : timeDomainDataList) {
            minValue = Math.min(minValue, value);
            maxValue = Math.max(maxValue, value);
        }
        for (float value : frequencyDomainDataList) {
            minValue = Math.min(minValue, value);
            maxValue = Math.max(maxValue, value);
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int width = getWidth();
        int height = getHeight();
        int halfHeight = height / 2;
        int dataSize = Math.min(timeDomainDataList.size(), frequencyDomainDataList.size());

        // 绘制坐标轴
        canvas.drawLine(0, halfHeight, width, halfHeight, axisPaint); // x 轴
        canvas.drawLine(0, 0, 0, height, axisPaint); // y 轴

        // 绘制坐标轴标注
        canvas.drawText(String.format(Locale.getDefault(), "%.2f", maxValue), 4, 24, textPaint); // 最大值
        canvas.drawText(String.format(Locale.getDefault(), "%.2f", minValue), 4, height - 4, textPaint); // 最小值
        canvas.drawText("时域", width - 200, halfHeight - 12, textPaint); // x 轴标注
        canvas.drawText("频域", width - 200, halfHeight + 24, textPaint); // y 轴标注

        // 绘制时域波形
        for (int i = 0; i < dataSize - 1; i++) {
            float x1 = (float) i * width / dataSize;
            float y1 = halfHeight - (timeDomainDataList.get(i) - minValue) / (maxValue - minValue) * halfHeight;
            float x2 = (float) (i + 1) * width / dataSize;
            float y2 = halfHeight - (timeDomainDataList.get(i + 1) - minValue) / (maxValue - minValue) * halfHeight;
            canvas.drawLine(x1, y1, x2, y2, timeDomainPaint);
        }

        // 绘制频域波形
        for (int i = 0; i < dataSize - 1; i++) {
            float x1 = (float) i * width / dataSize;
            float y1 = height - (frequencyDomainDataList.get(i) - minValue) / (maxValue - minValue) * height;
            float x2 = (float) (i + 1) * width / dataSize;
            float y2 = height - (frequencyDomainDataList.get(i + 1) - minValue) / (maxValue - minValue) * height;
            canvas.drawLine(x1, y1, x2, y2, frequencyDomainPaint);
        }
    }
}

4.效果展示