问题：-相机预览不同于使用 Camera2 API 拍摄的图像。并且该问题仅在横向模式下发生。
要求：-我的要求是使用camera2 api以横向模式捕获图像。相机预览应全屏显示。
我遵循了以下 github 示例：- https://github.com/googlesamples/android-Camera2Basic
此示例在纵向模式下工作正常，如果在保持纵横比时wrap_content纹理视图，则在横向模式下工作正常。
但是为了全屏显示相机预览，我将TextureView更改为match_parent。通过这样做，输出发生了变化。现在相机的预览与捕获的图像不同。
请查看此处随附的图片。
1.相机预览：-相机预览截图
2.图像捕获：-点击图片按钮
以下是我的代码片段：-
fragment_camera2_basic.xml
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.android.camera2basic.AutoFitTextureView
android:id="@+id/texture"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true" />
<FrameLayout
android:id="@+id/control"
android:layout_width="match_parent"
android:layout_height="112dp"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:background="@color/control_background">
<Button
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/picture" />
<ImageButton
android:id="@+id/info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|right"
android:padding="20dp"
android:src="@drawable/ic_action_info" />
</FrameLayout>
</RelativeLayout>
以下是捕获图像的代码：-
/**
* Initiate a still image capture.
*/
private void takePicture() {
lockFocus();
}
/**
* Lock the focus as the first step for a still image capture.
*/
private void lockFocus() {
try {
// This is how to tell the camera to lock focus.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
CameraMetadata.CONTROL_AF_TRIGGER_START);
// Tell #mCaptureCallback to wait for the lock.
mState = STATE_WAITING_LOCK;
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* Run the precapture sequence for capturing a still image. This method should be called when
* we get a response in {@link #mCaptureCallback} from {@link #lockFocus()}.
*/
private void runPrecaptureSequence() {
try {
// This is how to tell the camera to trigger.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
// Tell #mCaptureCallback to wait for the precapture sequence to be set.
mState = STATE_WAITING_PRECAPTURE;
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* Capture a still picture. This method should be called when we get a response in
* {@link #mCaptureCallback} from both {@link #lockFocus()}.
*/
private void captureStillPicture() {
try {
final Activity activity = getActivity();
if (null == activity || null == mCameraDevice) {
return;
}
// This is the CaptureRequest.Builder that we use to take a picture.
final CaptureRequest.Builder captureBuilder =
mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(mImageReader.getSurface());
// Use the same AE and AF modes as the preview.
captureBuilder.set(CaptureRequest.CONTROL_AF_MODE,
CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
setAutoFlash(captureBuilder);
// Orientation
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getOrientation(rotation));
CameraCaptureSession.CaptureCallback CaptureCallback
= new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request,
@NonNull TotalCaptureResult result) {
showToast("Saved: " + mFile);
Log.d(TAG, mFile.toString());
unlockFocus();
}
};
mCaptureSession.stopRepeating();
mCaptureSession.abortCaptures();
mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* Retrieves the JPEG orientation from the specified screen rotation.
*
* @param rotation The screen rotation.
* @return The JPEG orientation (one of 0, 90, 270, and 360)
*/
private int getOrientation(int rotation) {
// Sensor orientation is 90 for most devices, or 270 for some devices (eg. Nexus 5X)
// We have to take that into account and rotate JPEG properly.
// For devices with orientation of 90, we simply return our mapping from ORIENTATIONS.
// For devices with orientation of 270, we need to rotate the JPEG 180 degrees.
return (ORIENTATIONS.get(rotation) + mSensorOrientation + 270) % 360;
}
/**
* Unlock the focus. This method should be called when still image capture sequence is
* finished.
*/
private void unlockFocus() {
try {
// Reset the auto-focus trigger
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
setAutoFlash(mPreviewRequestBuilder);
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
// After this, the camera will go back to the normal state of preview.
mState = STATE_PREVIEW;
mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
我也尝试在相机预览生成器和图像阅读器中设置CaptureRequest.SCALER_CROP_REGION，但它没有按预期工作。
就布局而言，TextureView可能部分位于显示器之外。
所以它被切断了。
您可能需要使用Android Studio的布局工具进行确认。
通常，除非您匹配纵横比，否则您无法获得相同的图像，因此，如果要全屏预览，则必须选择与屏幕匹配的 JPEG 纵横比。
这可能无法直接从相机获得，因此您可能需要自己裁剪 JPEG。但最有可能的是，您至少可以获得 16：9 预览并且仍然相对容易地捕获，与 4：3 的最大静止捕获大小相比，黑条相对较小。