如何在 SurfaceView 上显示相机预览？
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【中文标题】如何在 SurfaceView 上显示相机预览？【英文标题】：How to show the camera preview on a SurfaceView? 【发布时间】：2017-02-15 01:03:00 【问题描述】：我正在尝试在 SurfaceView 上打开相机硬件。在布局中，我创建了一个 SurfaceView 并打开相机，如下面的代码所示。当我运行代码时，CameraAvailableCB 中的 toast 出现并显示“onCameraAvailable”，但 SurfaceView 上没有出现任何内容。
如何在 SurfaceView 上显示相机显示？
代码
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.mBtnCapture = (Button) findViewById(R.id.actMain_btn_capture);
this.mSurfaceView = (SurfaceView) findViewById(R.id.actMain_surfaceView);
this.mSurfaceHolder = this.mSurfaceView.getHolder();
this.mSurfaceHolder.addCallback(this);
this.mCameraManager = (CameraManager) this.getSystemService(Context.CAMERA_SERVICE);
try
cameraIDsList = this.mCameraManager.getCameraIdList();
for (String id : cameraIDsList)
Log.v(TAG, "CameraID: " + id);
catch (CameraAccessException e)
e.printStackTrace();
cameraStateCB = new CameraDevice.StateCallback()
@Override
public void onOpened(CameraDevice camera)
Toast.makeText(getApplicationContext(), "onOpened", Toast.LENGTH_SHORT).show();
//requesting permission
int permissionCheck = ContextCompat.checkSelfPermission(activity, Manifest.permission.CAMERA);
if (permissionCheck != PackageManager.PERMISSION_GRANTED)
if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.CAMERA))
else
ActivityCompat.requestPermissions(activity, new String[]Manifest.permission.CAMERA, MY_PERMISSIONS_REQUEST_CAMERA);
Toast.makeText(getApplicationContext(), "request permission", Toast.LENGTH_SHORT).show();
else
Toast.makeText(getApplicationContext(), "PERMISSION_ALREADY_GRANTED", Toast.LENGTH_SHORT).show();
//opening the camera
try
mCameraManager.openCamera(cameraIDsList[1], cameraStateCB, new Handler());
catch (CameraAccessException e)
e.printStackTrace();
@Override
public void onDisconnected(CameraDevice camera)
Toast.makeText(getApplicationContext(), "onDisconnected", Toast.LENGTH_SHORT).show();
@Override
public void onError(CameraDevice camera, int error)
Toast.makeText(getApplicationContext(), "onError", Toast.LENGTH_SHORT).show();
;
CameraManager.AvailabilityCallback cameraAvailableCB = new CameraManager.AvailabilityCallback()
@Override
public void onCameraAvailable(String cameraId)
super.onCameraAvailable(cameraId);
Toast.makeText(getApplicationContext(), "onCameraAvailable", Toast.LENGTH_SHORT).show();
@Override
public void onCameraUnavailable(String cameraId)
super.onCameraUnavailable(cameraId);
Toast.makeText(getApplicationContext(), "onCameraUnavailable", Toast.LENGTH_SHORT).show();
;
this.mCameraManager.registerAvailabilityCallback(cameraAvailableCB, new Handler());
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
case MY_PERMISSIONS_REQUEST_CAMERA:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
// Open Camera
break;
@Override
public void surfaceCreated(SurfaceHolder holder)
Log.w(TAG, "surfaceCreated");
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)
Log.w(TAG, "surfaceChanged");
@Override
public void surfaceDestroyed(SurfaceHolder holder)
Log.w(TAG, "surfaceDestroyed");
【问题讨论】：
那么，“onOpened”toast 也没有出现？ @AlexCohn 有时会出现 【参考方案1】：要使用 Camera2 API 从相机显示预览，您应该执行以下步骤：
-
获取使用相机设备的权限
使用 CameraManager 打开与相机的连接
已准备好 Surface 以供预览
使用打开的相机设备和所需的表面（它不仅可以包括预览表面）创建 CaptureSession
创建 CaptureSession 后，您需要创建和配置 CaptureRequest 并将其提交给 CaptureSession
需要注意，准备表面和打开与相机的连接是独立的过程，因此您需要确保它们都在创建 CaptureSession 之前完成。
这是在屏幕上显示相机预览的 Activity 示例：
public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback, Handler.Callback
static final String TAG = "CamTest";
static final int MY_PERMISSIONS_REQUEST_CAMERA = 1242;
private static final int MSG_CAMERA_OPENED = 1;
private static final int MSG_SURFACE_READY = 2;
private final Handler mHandler = new Handler(this);
SurfaceView mSurfaceView;
SurfaceHolder mSurfaceHolder;
CameraManager mCameraManager;
String[] mCameraIDsList;
CameraDevice.StateCallback mCameraStateCB;
CameraDevice mCameraDevice;
CameraCaptureSession mCaptureSession;
boolean mSurfaceCreated = true;
boolean mIsCameraConfigured = false;
private Surface mCameraSurface = null;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.mSurfaceView = (SurfaceView) findViewById(R.id.SurfaceViewPreview);
this.mSurfaceHolder = this.mSurfaceView.getHolder();
this.mSurfaceHolder.addCallback(this);
this.mCameraManager = (CameraManager) this.getSystemService(Context.CAMERA_SERVICE);
try
mCameraIDsList = this.mCameraManager.getCameraIdList();
for (String id : mCameraIDsList)
Log.v(TAG, "CameraID: " + id);
catch (CameraAccessException e)
e.printStackTrace();
mCameraStateCB = new CameraDevice.StateCallback()
@Override
public void onOpened(CameraDevice camera)
Toast.makeText(getApplicationContext(), "onOpened", Toast.LENGTH_SHORT).show();
mCameraDevice = camera;
mHandler.sendEmptyMessage(MSG_CAMERA_OPENED);
@Override
public void onDisconnected(CameraDevice camera)
Toast.makeText(getApplicationContext(), "onDisconnected", Toast.LENGTH_SHORT).show();
@Override
public void onError(CameraDevice camera, int error)
Toast.makeText(getApplicationContext(), "onError", Toast.LENGTH_SHORT).show();
;
@Override
protected void onStart()
super.onStart();
//requesting permission
int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
if (permissionCheck != PackageManager.PERMISSION_GRANTED)
if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA))
else
ActivityCompat.requestPermissions(this, new String[]Manifest.permission.CAMERA, MY_PERMISSIONS_REQUEST_CAMERA);
Toast.makeText(getApplicationContext(), "request permission", Toast.LENGTH_SHORT).show();
else
Toast.makeText(getApplicationContext(), "PERMISSION_ALREADY_GRANTED", Toast.LENGTH_SHORT).show();
try
mCameraManager.openCamera(mCameraIDsList[1], mCameraStateCB, new Handler());
catch (CameraAccessException e)
e.printStackTrace();
@Override
protected void onStop()
super.onStop();
try
if (mCaptureSession != null)
mCaptureSession.stopRepeating();
mCaptureSession.close();
mCaptureSession = null;
mIsCameraConfigured = false;
catch (final CameraAccessException e)
// Doesn't matter, cloising device anyway
e.printStackTrace();
catch (final IllegalStateException e2)
// Doesn't matter, cloising device anyway
e2.printStackTrace();
finally
if (mCameraDevice != null)
mCameraDevice.close();
mCameraDevice = null;
mCaptureSession = null;
@Override
public boolean handleMessage(Message msg)
switch (msg.what)
case MSG_CAMERA_OPENED:
case MSG_SURFACE_READY:
// if both surface is created and camera device is opened
// - ready to set up preview and other things
if (mSurfaceCreated && (mCameraDevice != null)
&& !mIsCameraConfigured)
configureCamera();
break;
return true;
private void configureCamera()
// prepare list of surfaces to be used in capture requests
List<Surface> sfl = new ArrayList<Surface>();
sfl.add(mCameraSurface); // surface for viewfinder preview
// configure camera with all the surfaces to be ever used
try
mCameraDevice.createCaptureSession(sfl,
new CaptureSessionListener(), null);
catch (CameraAccessException e)
e.printStackTrace();
mIsCameraConfigured = true;
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
case MY_PERMISSIONS_REQUEST_CAMERA:
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED)
try
mCameraManager.openCamera(mCameraIDsList[1], mCameraStateCB, new Handler());
catch (CameraAccessException e)
e.printStackTrace();
break;
@Override
public void surfaceCreated(SurfaceHolder holder)
mCameraSurface = holder.getSurface();
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)
mCameraSurface = holder.getSurface();
mSurfaceCreated = true;
mHandler.sendEmptyMessage(MSG_SURFACE_READY);
@Override
public void surfaceDestroyed(SurfaceHolder holder)
mSurfaceCreated = false;
private class CaptureSessionListener extends
CameraCaptureSession.StateCallback
@Override
public void onConfigureFailed(final CameraCaptureSession session)
Log.d(TAG, "CaptureSessionConfigure failed");
@Override
public void onConfigured(final CameraCaptureSession session)
Log.d(TAG, "CaptureSessionConfigure onConfigured");
mCaptureSession = session;
try
CaptureRequest.Builder previewRequestBuilder = mCameraDevice
.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
previewRequestBuilder.addTarget(mCameraSurface);
mCaptureSession.setRepeatingRequest(previewRequestBuilder.build(),
null, null);
catch (CameraAccessException e)
Log.d(TAG, "setting up preview failed");
e.printStackTrace();
【讨论】：
kotin 有这个吗？ @MosesLiaoGZ 对不起，没有 谢谢，我猜...但是这有点荒谬，需要像这样的大量代码来显示一个该死的相机预览... @BadCash 虽然这是执行看似简单的任务的大量代码，但谷歌制作的软件包可以为您轻松完成。看看CameraView @HamzaAbdullah 尝试将 'mCameraIDsList[1]' 更改为 'mCameraIDsList[0]'【参考方案2】：有了 CameraX，现在很容易。
// Create a preview use case instance
val preview = Preview.Builder().build()
// Bind the preview use case and other needed user cases to a lifecycle
val camera = cameraProvider.bindToLifecycle(lifecycleOwner, cameraSelector, preview, imageAnalysis, imageCapture)
// Create a surfaceProvider using the bound camera's cameraInfo
val surfaceProvider = previewView.createSurfaceProvider(camera.cameraInfo)
// Attach the surfaceProvider to the preview use case to start preview
preview.setSurfaceProvider(surfaceProvider)
<androidx.camera.view.PreviewView
android:layout_
android:layout_
app:scaleType="fitEnd" />
https://medium.com/androiddevelopers/display-a-camera-preview-with-previewview-86562433d86c
【讨论】：
问题要求在 SurfaceView 上渲染，而不是 PreviewView。以上是关于如何在 SurfaceView 上显示相机预览？的主要内容，如果未能解决你的问题，请参考以下文章
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