我制作了一个条形码检测应用程序,所以我使用SurfaceView来处理相机源。当相机检测到条形码并返回其值后,我让它停止。没有任何事件可以重新启动相机源和SurfaceView的功能,只有一个函数camerasource.start()。
它能够启动,但问题在于它在后台运行,我无法看到任何东西,如何解决这个问题?并再次显示SurfaceView和相机源。
以下是整个活动onCreate方法的代码:
它能够启动,但问题在于它在后台运行,我无法看到任何东西,如何解决这个问题?并再次显示SurfaceView和相机源。
以下是整个活动onCreate方法的代码:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView = (SurfaceView) findViewById(R.id.cameraPreview);
txtShow = (TextView) findViewById(R.id.txtShow);
startBarcode();
}
public void startBarcode() {
barcodeDetector = new BarcodeDetector.Builder(this)
.setBarcodeFormats(Barcode.ALL_FORMATS)
.build();
cameraSource = new CameraSource.Builder(this, barcodeDetector)
.setRequestedPreviewSize(800, 600)
.setAutoFocusEnabled(true)
.build();
//Events
surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start(surfaceView.getHolder());
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
cameraSource.stop();
}
});
barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
@Override
public void release() {
}
@Override
public void receiveDetections(Detector.Detections<Barcode> detections) {
final SparseArray<Barcode> qrCodes = detections.getDetectedItems();
if (qrCodes.size() != 0) {
txtShow.post(new Runnable() {
@Override
public void run() {
//create vibrate
Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
vibrator.vibrate(500);
//set result for Text View
txtShow.setText(qrCodes.valueAt(0).displayValue);
// surfaceView.setTop(200);
cameraSource.stop();
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.barcode);
mp.start();