我如何让 asynctask 抛出 WriterException？

Question

当我尝试编写这样的代码时出现此错误：

doInBackground(String...)' 在 'com.....QrGenerator' 中与 'doInBackground(Params...)' 在 'android.os.AsyncTask' 中冲突；重写的方法不会抛出 'com.google.zxing.WriterException'

代码如下：

private class QrGenerator extends AsyncTask<String,Integer,Bitmap>{
    @Override
    protected Bitmap doInBackground(String... strings) throws WriterException  {

    StringBuilder strBuilder = new StringBuilder();
    for (int i = 0; i < strings.length; i++) {
       strBuilder.append(strings[i]);
    }
    String value = strBuilder.toString();

    BitMatrix bitMatrix;
    try {
        bitMatrix = new MultiFormatWriter().encode(
                value,
                BarcodeFormat.DATA_MATRIX.QR_CODE,
                QRcodeWidth, QRcodeWidth, null
        );

    } catch (IllegalArgumentException Illegalargumentexception) {

        return null;
    }
    int bitMatrixWidth = bitMatrix.getWidth();

    int bitMatrixHeight = bitMatrix.getHeight();

    int[] pixels = new int[bitMatrixWidth * bitMatrixHeight];

    for (int y = 0; y < bitMatrixHeight; y++) {
        int offset = y * bitMatrixWidth;

        for (int x = 0; x < bitMatrixWidth; x++) {

            pixels[offset + x] = bitMatrix.get(x, y) ?
                    getResources().getColor(R.color.QRCodeBlackColor) : getResources().getColor(R.color.QRCodeWhiteColor);
        }
    }
    Bitmap bitmap = Bitmap.createBitmap(bitMatrixWidth, bitMatrixHeight, Bitmap.Config.ARGB_4444);

    bitmap.setPixels(pixels, 0, 500, 0, 0, bitMatrixWidth, bitMatrixHeight);
    return bitmap;
}

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        super.onPostExecute(bitmap);
        imageView.setImageBitmap(bitmap);
    }
}

Answer 1

您不能在覆盖的方法中抛出额外的异常，例如 doInBackground(...)。参见 this link。您必须在方法中捕获异常。我修改了您的方法以捕获 WriterException。

try {
    bitMatrix = new MultiFormatWriter().encode(
            value,
            BarcodeFormat.DATA_MATRIX.QR_CODE,
            33, 33, null
    );

} catch (IllegalArgumentException | WriterException e1) {
    e1.printStackTrace();
    return null;
}

我如何让 asynctask 抛出 WriterException？

how do i make asynctask throw WriterException?

java

android

android-asynctask

try-catch

throws