android - 如何在 Android 的 TextView 中的文本下方添加红色波浪线

Question

我正在尝试在文本错误下方添加红色波浪线，例如:

不幸的是，我找不到合适的 *Span 类来包装错误文本。

我应该如何在 Android 中实现这样的功能？

Answer 1

这是一个不涉及资源的解决方案:

public class WavyUnderlineSpan implements LineBackgroundSpan {

private int color;
private int lineWidth;
private int waveSize;

public WavyUnderlineSpan() {
    this(Color.RED, 1, 3);
}

public WavyUnderlineSpan(int color, int lineWidth, int waveSize) {
    this.color = color;
    this.lineWidth = lineWidth;
    this.waveSize = waveSize;
}

@Override
public void drawBackground(Canvas canvas, Paint paint, int left, int right, int top, int baseline, int bottom,
                           CharSequence text, int start, int end, int lnum) {
    Paint p = new Paint(paint);
    p.setColor(color);
    p.setStrokeWidth(lineWidth);

    int width = (int) paint.measureText(text, start, end);
    int doubleWaveSize = waveSize * 2;
    for (int i = left; i < left + width; i += doubleWaveSize) {
        canvas.drawLine(i, bottom, i + waveSize, bottom - waveSize, p);
        canvas.drawLine(i + waveSize, bottom - waveSize, i + doubleWaveSize, bottom, p);
    }
}