android 自定义 TextView 点击字体镂空效果

网上好多字体镂空效果都是单行的，及没有点击效果的，所以，我没办法就自己写了一个TextView ，目的是自定义这个，点击的时候才是镂空效果，但是，平时的时候是常态，就像是selector一样，这是一个工具类，你们拿去直接用就行了

public class ShowPalettePageTextView extends View {

    public static final int BACKGROUND_COLOR = MyApp.getAppColor(R.color.color_dialog_text_content);
    private static final int DEFAULT_RADIUS = MyApp.getAppDimen(R.dimen.default_radio_size);
    private TextPaint mTextPaint;
    private Paint mBackgroundPaint;
    private RectF mBackgroundRect;
    private boolean isPressed = false;
    private String mShowPageText;

    private Xfermode xfermode = new PorterDuffXfermode(PorterDuff.Mode.CLEAR);

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

    public ShowPalettePageTextView(Context context, AttributeSet attrs) {
        this(context, attrs, -1);
    }

    public ShowPalettePageTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mTextPaint = new TextPaint();
        mTextPaint.setAntiAlias(true);
        mTextPaint.setColor(BACKGROUND_COLOR);
        mTextPaint.setTextSize(MyApp.getAppDimen(R.dimen.text_size));
        mBackgroundPaint = new Paint();
        mBackgroundPaint.setColor(BACKGROUND_COLOR);
        mBackgroundPaint.setAntiAlias(true);
        mBackgroundRect = new RectF();
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldw, int oldh) {
        super.onSizeChanged(width, height, oldw, oldh);
        mBackgroundRect.set(0, 0, width, height);
    }

    public void setText(String showPageText) {
        this.mShowPageText = showPageText;
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        drawBackground(canvas);
        drawText(canvas);
    }

    private void drawBackground(Canvas canvas) {
        if (isPressed) {
            mBackgroundPaint.setStyle(Paint.Style.FILL);
        } else {
            mBackgroundPaint.setStyle(Paint.Style.STROKE);
        }
        canvas.drawRoundRect(mBackgroundRect, DEFAULT_RADIUS, DEFAULT_RADIUS, mBackgroundPaint);
    }

    private void drawText(Canvas canvas) {
        if (mShowPageText == null) {
            return;
        }
        if (isPressed) {
            mTextPaint.setXfermode(xfermode);
        } else {
            mTextPaint.setXfermode(null);
        }
        float x = mBackgroundRect.width() / 2 - mTextPaint.measureText(mShowPageText) / 2;
        float y = mBackgroundRect.top + mBackgroundRect.height() / 2 + mTextPaint.getTextSize() / 3;
        canvas.drawText(mShowPageText, x, y, mTextPaint);
    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            isPressed = true;
            invalidate();
        } else if (event.getAction() == MotionEvent.ACTION_UP) {
            isPressed = false;
            invalidate();
        }
        return super.onTouchEvent(event);
    }

}