相机预览在少数 Android 设备上延伸
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【中文标题】相机预览在少数 Android 设备上延伸【英文标题】：Camera Preview Stretched on Few Android Devices 【发布时间】：2015-07-14 23:16:42 【问题描述】：我正在为 android 应用程序制作像“SnapChat”这样的自定义相机，但相机预览在少数设备（如（Moto g 第二代，一加一）上拉伸，但不是（三星 s3，三星 s4）。我使用了以下参考资料Camera display / preview in full screen does not maintain aspect ratio - image is skewed, stretched in order to fit on the screen。但这对我没有 100% 的帮助。我正在共享屏幕。
三星 Moto G 第二代的拉伸图像是。
未拉伸的三星S3图片在上方
private void setPreviewLayout()
if (null == mCamera)
return;
Camera.Parameters parameters = null;
Camera.Size size = null;
try
int screenWidth = (int) getResources().getDisplayMetrics().widthPixels;
int screenHeight = (int) getResources().getDisplayMetrics().heightPixels;
parameters = mCamera.getParameters();
size = getOptimalPreviewSize(mCamera.getParameters().getSupportedPreviewSizes(), screenWidth, screenHeight);
if (size != null)
parameters.setPreviewSize(size.width, size.height);
parameters.setPictureSize(screenHeight, screenWidth);
;
mCamera.setParameters(parameters);
if (on && currentCameraId == Camera.CameraInfo.CAMERA_FACING_BACK)
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
else
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
parameters.setWhiteBalance(Camera.Parameters.WHITE_BALANCE_AUTO);
parameters.setExposureCompensation(0);
parameters.setPictureFormat(ImageFormat.JPEG);
parameters.setJpegQuality(100);
List<String> focusModes = parameters.getSupportedFocusModes();
if (focusModes.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE))
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
else if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO))
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
mCamera.setParameters(parameters);
/*
* camera.setPreviewDisplay(surfaceHolder); camera.startPreview();
*/
catch (Exception e)
e.printStackTrace();
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h)
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) h / w;
if (sizes == null)
return null;
Camera.Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
for (Camera.Size size : sizes)
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
continue;
if (Math.abs(size.height - targetHeight) < minDiff)
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
if (optimalSize == null)
minDiff = Double.MAX_VALUE;
for (Camera.Size size : sizes)
if (Math.abs(size.height - targetHeight) < minDiff)
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
return optimalSize;
【问题讨论】：
谁能帮帮我？ 【参考方案1】：使用getOptimalPreviewSize() 很重要，但它并不能解决所有布局中所有设备上的所有拉伸问题。您必须准备好对预览进行一点裁剪，以便预览填满屏幕而不会失真。
有不同的技术可以强制使表面的大小与实际屏幕大小不同，但我认为这是最简单的一种：
我将CameraView 添加到我的布局中：
public class CameraView extends SurfaceView implements SurfaceHolder.Callback
public CameraView(Context context, AttributeSet attr)
super(context, attr);
// install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
getHolder().addCallback(this);
@Override public void surfaceCreated(SurfaceHolder holder)
openCamera();
bCameraInitialized = false;
@Override public void surfaceDestroyed(SurfaceHolder holder)
camera.release();
@Override public void surfaceChanged(SurfaceHolder holder,
int format, int w, int h)
if (bCameraInitialized)
// we will get here after we have resized the surface, see below
return;
cameraSetup(w, h);
bCameraInitialized = true;
private void cameraSetup(int w, int h)
// set the camera parameters, including the preview size
FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) getLayoutParams();
double cameraAspectRatio = ((double)optimalSize.width)/optimalSize.height;
if (((double)h)/w > cameraAspectRatio)
lp.width = (int)(h/cameraAspectRatio+0.5);
lp.height = h;
else
lp.height = (int)(w*cameraAspectRatio + 0.5);
lp.width = w;
lp.topMargin = (h - lp.height)/2;
lp.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
setLayoutParams(lp);
requestLayout();
为了强调主旨，我没有包括错误处理，这里也没有展示相机is actually started with a secondary Looper是怎么做的。
【讨论】：
我使用了您的代码，但这并不能解决我的问题。我正在使用 TextureView.SurfaceTextureListener 而不是 Surface 视图。你可以在Skype sachin.auxiliumit 上加我或给我你的Skype id。我真的会非常感谢你。 直到明天我才能在 Skype 上使用。我相信即使使用 TextureView 你仍然有相同的布局事件。您可以使用onMeasure() 如上所述，或OnLayoutListener - 无论是什么类型，您都需要为您的视图设置固定的宽度和高度 - 并可能在其容器中居中。
@SandeepVishwakarma 我面临同样的问题。我正在使用camera2和TextureView。您找到解决方案了吗？【参考方案2】：
需要重写SurfaceView类的onMeasure方法来获取surfaceview的宽高
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null)
mPreviewSize = getOptimalPreviewSize(mCamera.getParameters().getSupportedPreviewSizes(), width, height);
然后将你得到的预览尺寸设置为相机参数预览尺寸。
cameraParameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
mCamera.setParameters(cameraParameters);
getSuggestedMinimumHeight()、getSuggestedMinimumWidth()是View类的方法
希望对你有帮助！！！
【讨论】：
嗨 Lakshay，我使用的是 TextureView.SurfaceTextureListener 而不是表面视图。它没有方法 onMeasure 。你能告诉我我该怎么做吗？ 你能详细说明一下你的代码吗？将不得不看到，因为我从未使用过讨论的 TextureView 侦听器【参考方案3】：试试这个，它正在工作......
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback
private static final String TAG = "Camera Preview";
private static final double PREVIEW_SIZE_FACTOR = 3.00;
private SurfaceHolder mHolder = null;
private Camera mCamera = null;
Camera.Parameters _parameters=null;
@SuppressWarnings("deprecation")
public CameraPreview(Context context, Camera camera)
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
public void surfaceCreated(SurfaceHolder holder)
// The Surface has been created, now tell the camera where to draw the preview.
try
Camera.Parameters parameters = mCamera.getParameters();
final Size mPreviewSize = getOptimalSize();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
//startContinuousAutoFocus();
catch (Exception e)
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
public void surfaceDestroyed(SurfaceHolder holder)
@SuppressLint("NewApi")
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h)
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null)
// preview surface does not exist
return;
// stop preview before making changes
try
mCamera.stopPreview();
catch (Exception e)
// ignore: tried to stop a non-existent preview
// set preview size and make any resize, rotate or
// reformatting changes here
// set Camera parameters
// start preview with new settings
try
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
catch (Exception e)
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
public void startPreview()
try
mCamera.startPreview();
catch (Exception e)
private Size getOptimalSize()
Camera.Size result = null;
final Camera.Parameters parameters = mCamera.getParameters();
Log.i(CameraPreview.class.getSimpleName(), "window width: " + getWidth() + ", height: " + getHeight());
for (final Camera.Size size : parameters.getSupportedPreviewSizes())
if (size.width <= getWidth() * PREVIEW_SIZE_FACTOR && size.height <= getHeight() * PREVIEW_SIZE_FACTOR)
if (result == null)
result = size;
else
final int resultArea = result.width * result.height;
final int newArea = size.width * size.height;
if (newArea > resultArea)
result = size;
if (result == null)
result = parameters.getSupportedPreviewSizes().get(0);
Log.i(CameraPreview.class.getSimpleName(), "Using PreviewSize: " + result.width + " x " + result.height);
return result;
【讨论】：
这不起作用。我正在使用 TextureView.SurfaceTextureListener 而不是表面视图，你能告诉我我该怎么做。以上是关于相机预览在少数 Android 设备上延伸的主要内容，如果未能解决你的问题，请参考以下文章