android - SurfaceView 显示黑屏 - Android Studio

Question

我希望能够扫描二维码，但是，当应用程序打开时它只显示黑屏

我已经尝试了好几天了。如果有人可以提供帮助，我真的很感激。它可能很小，但我似乎找不到解决方案

MainActivity 类

public class MainActivity extends AppCompatActivity {
SurfaceView surfaceView;
CameraSource cameraSource;
TextView textView;
BarcodeDetector barcodeDetector;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    surfaceView = (SurfaceView) findViewById(R.id.camerapreview);
    textView = (TextView) findViewById(R.id.textView);

    barcodeDetector = new BarcodeDetector.Builder(this)
            .setBarcodeFormats(Barcode.QR_CODE).build();

    cameraSource = new CameraSource.Builder(this, barcodeDetector)
            .setRequestedPreviewSize(640, 480).build();


    surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(@NonNull SurfaceHolder holder) {


            if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {

                return;
            }
            try {

                cameraSource.start(holder);

            } catch (IOException e) {
                e.printStackTrace();

            }


        }

        @Override
        public void surfaceChanged(@NonNull SurfaceHolder holder, int format, int width, int height) {

        }

        @Override
        public void surfaceDestroyed(@NonNull SurfaceHolder holder) {
            cameraSource.stop();
        }
    });

    barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
        @Override
        public void release() {

        }

        @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {
            SparseArray<Barcode> qrCodes = detections.getDetectedItems();

            if (qrCodes.size() != 0) {
                textView.post(new Runnable() {
                    @Override
                    public void run() {
                        Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
                        vibrator.vibrate(1000);
                        textView.setText(qrCodes.valueAt(0).displayValue);
                    }
                });


            }

        }

    });

}

}

安卓清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.barcodescanner">


<uses-feature
    android:name="android.hardware.camera"
    android:required="true" />

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-permission android:name="android.permission.VIBRATE" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.BarcodeScanner">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <meta-data android:name="com.google.android.gms.vision.DEPENDENCIES" android:value="barcode"></meta-data>
</application>

主要活动 XML

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


<SurfaceView
    android:layout_width="match_parent"
    android:layout_height="300dp"
    android:id="@+id/camerapreview"
    android:layout_centerInParent="true"
    />




<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/textView"
    android:layout_below="@+id/camerapreview"
    android:layout_marginTop="20dp"
    android:text="Please focus on QR code"
    android:textSize="18sp"
    android:gravity="center"/>

有什么我想念的吗？提前致谢

标签： androidandroid-layoutqr-codesurfaceviewbarcode-scanner

Answer 1

希望这可以帮助你：

主要活动

private static final int REQUEST_CAMERA_PERMISSION = 201;

您应该添加 setAutoFocusEnabled(true) 功能

cameraSource = new CameraSource.Builder(this, barcodeDetector)
                .setRequestedPreviewSize(1920, 1080)
                .setAutoFocusEnabled(true).build();

surfaceCreated 函数检查权限

 @Override
            public void surfaceCreated(SurfaceHolder holder) {
                try {
                    if (ActivityCompat.checkSelfPermission(ScannedBarcodeActivity.this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
                        cameraSource.start(surfaceView.getHolder());
                    } else {
                        ActivityCompat.requestPermissions(ScannedBarcodeActivity.this, new
                                String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }


            }

接收检测函数

qrCodes.valueAt(0).displayValue;