Android：HTC EVO上的相机预览定位（Android 2.1或2.2）(Android: Camera Preview Orientation on HTC EVO (Android 2.1 or 2.2))

 我正在开发一个依赖于相机API的Android应用程序，使用HTC EVO作为我的测试设备。 无论我到目前为止尝试过什么，相机预览看起来正确的唯一时间是横向模式（旋转90度，具体而言）。 在纵向模式（0度旋转）下，似乎无法正确定位预览。 
 
 设备上的默认摄像头应用程序（用于HTC Sense）允许任何类型的旋转而没有任何问题，因此我知道没有硬件限制。 我甚至从HTC的开发者网站上下载了一些源代码，但显然它都是C内核的东西。 
 
 任何人都可以指出我正确的方向来解决这个问题吗？ 有没有办法在Android 2.1或2.2中正确旋转预览？ 
 
 谢谢。 
 
 PS这是我正在使用的代码，如果它有帮助...... 
 
package spikes.cameraSpike03;

import java.util.List;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;

public class MainActivity extends Activity implements SurfaceHolder.Callback {
 private static final String LOG_TAG = "spikes.cameraSpike03 - MainActivity";

 private Camera _camera;
 private boolean _previewIsRunning = false;

 private SurfaceView _svCameraView;
 private SurfaceHolder _surfaceHolder;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.main);

        _svCameraView = (SurfaceView)findViewById(R.id.svCameraView);

        _surfaceHolder = _svCameraView.getHolder();
        _surfaceHolder.addCallback(this);
        _surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
  if(_previewIsRunning){
   _camera.stopPreview();
  }

  try{
   Camera.Parameters parameters = _camera.getParameters();

   //Get the optimal preview size so we don't get an exception when setting the parameters 
   List<Size> supportedPreviewSizes = parameters.getSupportedPreviewSizes();
   Size optimalPreviewSize = getOptimalPreviewSize(supportedPreviewSizes, width, height);
   parameters.setPreviewSize(optimalPreviewSize.width, optimalPreviewSize.height);

   _camera.setParameters(parameters);

   _camera.setPreviewDisplay(holder);
  }
  catch(Exception ex){
   ex.printStackTrace();
   Log.e(LOG_TAG, ex.toString());
  }

  _camera.startPreview();
  _previewIsRunning = true;
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  _camera = Camera.open();
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  _camera.stopPreview();
  _previewIsRunning = false;
  _camera.release();
 }

 private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.05;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (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);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }

}

I am developing an Android application that relies on the camera API, using an HTC EVO as my testing device. No matter what I've tried so far, the only time the camera preview looks right is in landscape mode (90 degrees rotation, to be specific). It seems as though there is no way to orient the preview correctly when in portrait mode (0 degrees rotation).
 
The default camera application on the device (for HTC Sense) allows for any kind of rotation without any problem, so I know that there is no hardware limitation. I even downloaded some source code from HTC's developer site, but it's all in C - kernel stuff, apparently.
 
Can anyone point me in the right direction for solving this problem? Is there a way to rotate the preview correctly in Android 2.1 or 2.2?
 
Thank you.
 
P.S. Here is the code I'm using, in case it helps...
 
package spikes.cameraSpike03;

import java.util.List;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;

public class MainActivity extends Activity implements SurfaceHolder.Callback {
 private static final String LOG_TAG = "spikes.cameraSpike03 - MainActivity";

 private Camera _camera;
 private boolean _previewIsRunning = false;

 private SurfaceView _svCameraView;
 private SurfaceHolder _surfaceHolder;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.main);

        _svCameraView = (SurfaceView)findViewById(R.id.svCameraView);

        _surfaceHolder = _svCameraView.getHolder();
        _surfaceHolder.addCallback(this);
        _surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
  if(_previewIsRunning){
   _camera.stopPreview();
  }

  try{
   Camera.Parameters parameters = _camera.getParameters();

   //Get the optimal preview size so we don't get an exception when setting the parameters 
   List<Size> supportedPreviewSizes = parameters.getSupportedPreviewSizes();
   Size optimalPreviewSize = getOptimalPreviewSize(supportedPreviewSizes, width, height);
   parameters.setPreviewSize(optimalPreviewSize.width, optimalPreviewSize.height);

   _camera.setParameters(parameters);

   _camera.setPreviewDisplay(holder);
  }
  catch(Exception ex){
   ex.printStackTrace();
   Log.e(LOG_TAG, ex.toString());
  }

  _camera.startPreview();
  _previewIsRunning = true;
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  _camera = Camera.open();
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  _camera.stopPreview();
  _previewIsRunning = false;
  _camera.release();
 }

 private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.05;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (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);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }

}

原文：https://stackoverflow.com/questions/4727957