android - 如何勾画一个TextView？

Question

我想做什么？(蓝色会变成白色)

我做了什么？
我找到了一个扩展 TextView 的类，它能够非常接近我想要的轮廓 textview。问题是我无法将描边颜色更改为任何颜色，它始终绘制为黑色。如何设置边框颜色为白色？

我的输出是什么:

我的代码在哪里？

public class TypeFaceTextView extends TextView {

private static Paint getWhiteBorderPaint(){
    Paint p = new Paint(Color.WHITE);
    return p;
}

private static final Paint BLACK_BORDER_PAINT = getWhiteBorderPaint();

static {
    BLACK_BORDER_PAINT.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
}

@Override
public void setText(CharSequence text, BufferType type) {

    super.setText(String.format(text.toString()), type);
}

private static final int BORDER_WIDTH = 1;

private Typeface typeface;

public TypeFaceTextView(Context context) {
    super(context);
}

public TypeFaceTextView(Context context, AttributeSet attrs) {
    super(context, attrs);

    setDrawingCacheEnabled(false);

    setTypeface(attrs);
}

private void setTypeface(AttributeSet attrs) {
    final String typefaceFileName = attrs.getAttributeValue(null, "typeface");
    if (typefaceFileName != null) {
        typeface = Typeface.createFromAsset(getContext().getAssets(), typefaceFileName);
    }

    setTypeface(typeface);
}

public TypeFaceTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);

    setTypeface(attrs);
}

@Override
public void draw(Canvas aCanvas) {
    aCanvas.saveLayer(null, BLACK_BORDER_PAINT, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG
            | Canvas.FULL_COLOR_LAYER_SAVE_FLAG | Canvas.MATRIX_SAVE_FLAG);

    drawBackground(aCanvas, -BORDER_WIDTH, -BORDER_WIDTH);
    drawBackground(aCanvas, BORDER_WIDTH + BORDER_WIDTH, 0);
    drawBackground(aCanvas, 0, BORDER_WIDTH + BORDER_WIDTH);
    drawBackground(aCanvas, -BORDER_WIDTH - BORDER_WIDTH, 0);

    aCanvas.restore();
    super.draw(aCanvas);

}

private void drawBackground(Canvas aCanvas, int aDX, int aDY) {
    aCanvas.translate(aDX, aDY);
    super.draw(aCanvas);
}
}

Answer 1

我找到了无需继承 TextView 即可勾勒 View 轮廓的简单方法。我写了一个简单的库，使用 Android 的 Spannable 来概述文本。该解决方案提供了仅概述部分文本的可能性。

图书馆:OutlineSpan

类(class)(只能复制类(class)):OutlineSpan