正如标题所说，这是我的问题。
我的相机成功进入前置摄像头，但点击第二个按钮后，它不会改变回到后视图并保持前视图。
CameraActivity.java：
package mano.whatever;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Picture;
import android.graphics.RectF;
import android.hardware.Camera;
import android.media.Image;
import android.net.Uri;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.annotation.Nullable;
import android.util.Base64;
import android.util.Log;
import android.view.View;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.Toast;
import android.os.AsyncTask;
import com.google.android.gms.identity.intents.AddressConstants;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
public class CameraActivity extends Activity {
private Camera.Size mSize = null;
private Camera mCamera = null;
private CameraView mCameraView=null;
private SurfaceView mPreview;
private SurfaceHolder mSurfaceHolder;
Camera.PictureCallback jpegCallback;
final int CAMERA_CAPTURE = 1;
private Camera.PictureCallback mPictureCallback;
boolean isFront;
int camBackId = Camera.CameraInfo.CAMERA_FACING_BACK;
int camFrontId = Camera.CameraInfo.CAMERA_FACING_FRONT;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
if (mCamera == null){
initCamera(0);
}
//btn to close the application
ImageView imgClose = (ImageView) findViewById(R.id.left_button);
imgClose.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
toThanksActivity();
}
});
ImageView photo = (ImageView) findViewById(R.id.photo_button);
photo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCamera.autoFocus(new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean b, Camera camera) {
mCamera.takePicture(shutterCall, PictureCallback, mPicture);
}
});
}
});
ImageView rotate = (ImageView) findViewById(R.id.rotate_camera);
rotate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
rotateCamera();
}
});
}
public void rotateCamera() {
boolean isFront = false;
int CamId = 0;
CamId = Camera.getNumberOfCameras();
int cameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
Camera.CameraInfo currentCamInfo = new Camera.CameraInfo();
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
if (currentCamInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK){
initCamera(1);
}
else{
initCamera(0);
}
}
public void initCamera(int potato){
mCamera = Camera.open(potato);//you can use open(int) to use different cameras
FrameLayout camera_view = (FrameLayout) findViewById(R.id.camera_view);
camera_view.removeView(mCameraView);
if (mCamera != null) {
mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
camera_view.addView(mCameraView);//add the SurfaceView to the layout
}
}
public void toThanksActivity() {
mCamera.stopPreview();
mCamera.release();
finish();
}
public void toCaptureImage() {
mCamera.takePicture(shutterCall, PictureCallback, mPicture);
}
Camera.ShutterCallback shutterCall = new Camera.ShutterCallback() {
@Override
public void onShutter() {
}
};
Camera.PictureCallback PictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] bytes, Camera camera) {
}
};
Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
String date = dateFormat.format(new Date());
String photoFile = "Picture_" + date + ".jpg";
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "Camera");
String filename = mediaStorageDir.getPath() + File.separator + photoFile;
File pictureFile = new File(filename);
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.flush();
fos.close();
ByteArrayOutputStream stream = new ByteArrayOutputStream();
Bitmap bm = BitmapFactory.decodeFile(filename);
Matrix matrix = new Matrix();
matrix.postRotate(90);
Bitmap rotatedBitmap = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), matrix, true);
FileOutputStream fos2 = new FileOutputStream(pictureFile);
rotatedBitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
byte[] byteArray = stream.toByteArray();
mCamera.stopPreview();
mCamera.release();
Intent intent = new Intent();
intent.putExtra("image", byteArray);
setResult(250, intent);
finish();
} catch (IOException e) {
}
}
};
Camera.AutoFocusCallback myAutoFocusCallback = new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean b, Camera camera) {
}
};
}
CameraView.java：
package mano.whatever;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.io.IOException;
import java.util.List;
public class CameraView extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
private Camera.Size mSize = null;
public CameraView(Context context, Camera camera) {
super(context);
mCamera = camera;
mCamera.setDisplayOrientation(90);
//get the holder and set this class as the callback, so we can get camera data here
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
//when the surface is created, we can set the camera to draw images in this surfaceholder
Camera.Parameters parameters = mCamera.getParameters();
List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
// You need to choose the most appropriate previewSize for your app
Size optimalSize = getOptimalPreviewSize(previewSizes, getResources().getDisplayMetrics().widthPixels, getResources().getDisplayMetrics().heightPixels);
parameters.setPreviewSize(optimalSize.width, optimalSize.height);
mCamera.setParameters(parameters);
mCamera.startPreview();
}
@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i2, int i3) {
//before changing the application orientation, you need to stop the preview, rotate and then start it again
if (mHolder.getSurface() == null)//check if the surface is ready to receive camera data
return;
try {
mCamera.stopPreview();
} catch (Exception e) {
//this will happen when you are trying the camera if it's not running
}
//now, recreate the camera preview
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (IOException e) {
Log.d("ERROR", "Camera error on surfaceChanged " + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
//our app has only one screen, so we'll destroy the camera in the surface
//if you are unsing with more screens, please move this code your activity
}
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;
}
}
我知道这是一个粗略的代码，但我很乐意听到一些建议。
提前谢谢。:)
修改
我完全重写了我的代码，摆脱了CameraView.java类，并且由于Android camera preview freezes when switching cameras?
它可以流畅地工作答案 0 :(得分：0)
没试过，但尝试这样的事情，希望它有效吗？
public void rotateCamera() {
boolean isFront = false;
int CamId = 0;
CamId = Camera.getNumberOfCameras();
int cameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
Camera.CameraInfo currentCamInfo = new Camera.CameraInfo();
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
if (currentCamInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK){
camera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);
}
else{
camera = Camera.open(Camera.CameraInfo.CAMERA_FACING_FRONT);
}
if (mCamera != null) {
try {
mCamera.setPreviewDisplay(surfaceView.getHolder());
mCamera.startPreview();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}