java - 使用Zxing库连续扫描二维码，无法打开相机

Question

我正在创建一个二维码扫描应用程序，它可以在不关闭相机的情况下连续扫描二维码并在同一屏幕上显示结果。

我正在使用 ZXing 库，但是当我触发连续扫描 Activity 时，它无法打开相机。我无法弄清楚这个问题。请检查，我已经在我的 list 中添加了相机权限。

代码:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.journeyapps.barcodescanner.DecoratedBarcodeView
        android:id="@+id/barcode_scanner"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_above="@+id/buttonsLayout"
        android:layout_alignParentTop="true">

    </com.journeyapps.barcodescanner.DecoratedBarcodeView>

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:id="@+id/buttonsLayout"
        android:layout_toLeftOf="@+id/centerHorizont">

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Pause"
            android:onClick="pause" />

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Resume"
            android:onClick="resume" />
    </LinearLayout>

    <View
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_centerHorizontal="true"
        android:id="@+id/centerHorizont" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/centerHorizont"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@id/buttonsLayout"
        android:id="@+id/barcodePreview" />

</RelativeLayout>

Java 代码:

public class ContinuousCaptureActivity extends Activity {
    private static final String TAG = ContinuousCaptureActivity.class.getSimpleName();
    private DecoratedBarcodeView barcodeView;
    private BeepManager beepManager;
    private String lastText;

    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if(result.getText() == null || result.getText().equals(lastText)) {
                // Prevent duplicate scans
                return;
            }

            lastText = result.getText();
            barcodeView.setStatusText(result.getText());

            beepManager.playBeepSoundAndVibrate();

            //Added preview of scanned barcode
           ImageView imageView = (ImageView) findViewById(R.id.barcodePreview);
           imageView.setImageBitmap(result.getBitmapWithResultPoints(Color.YELLOW));
        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.continuous_scan);

        barcodeView = (DecoratedBarcodeView) findViewById(R.id.barcode_scanner);
        Collection<BarcodeFormat> formats = Arrays.asList(BarcodeFormat.QR_CODE, BarcodeFormat.CODE_39);
        barcodeView.getBarcodeView().setDecoderFactory(new DefaultDecoderFactory(formats));
        barcodeView.decodeContinuous(callback);

        beepManager = new BeepManager(this);
    }

    @Override
    protected void onResume() {
        super.onResume();

        barcodeView.resume();
    }

    @Override
    protected void onPause() {
        super.onPause();

        barcodeView.pause();
    }

    public void pause(View view) {
        barcodeView.pause();
    }

    public void resume(View view) {
        barcodeView.resume();
    }

    public void triggerScan(View view) {
        barcodeView.decodeSingle(callback);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        return barcodeView.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event);
    }

这是错误信息，我明白了!

Answer 1

问题的发生是因为权限。我已添加代码以手动请求权限，现在问题已解决。

感谢@Roberto Manfreda