我使用以下课程在Android上拍照，我想用前置相机拍照。我已将所需权限添加到清单文件中：
public class CameraController extends AsyncTask{
final Context context;
private boolean hasCamera;
private Camera camera;
private int cameraId;
public CameraController(Context c){
context = c.getApplicationContext();
if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
cameraId = getFrontCameraId();
if(cameraId != -1){
hasCamera = true;
}else{
hasCamera = false;
}
}else{
hasCamera = false;
}
}
public void getCameraInstance(){
camera = null;
if(hasCamera){
try{
camera = Camera.open(cameraId);
prepareCamera();
}
catch(Exception e){
hasCamera = false;
}
}
}
public void takePicture(){
if(hasCamera){
camera.takePicture(null,null,mPicture);
}
}
public void releaseCamera(){
if(camera != null){
camera.stopPreview();
camera.release();
camera = null;
}
}
private int getFrontCameraId(){
int camId = -1;
int numberOfCameras = Camera.getNumberOfCameras();
CameraInfo ci = new CameraInfo();
for(int i = 0;i < numberOfCameras;i++){
Camera.getCameraInfo(i,ci);
if(ci.facing == CameraInfo.CAMERA_FACING_FRONT){
camId = i;
}
}
return camId;
}
private void prepareCamera(){
SurfaceView view = new SurfaceView(context);
try{
camera.setPreviewDisplay(view.getHolder());
}catch(IOException e){
throw new RuntimeException(e);
}
camera.startPreview();
Camera.Parameters params = camera.getParameters();
params.setJpegQuality(100);
camera.setParameters(params);
}
private Camera.PictureCallback mPicture = new Camera.PictureCallback(){
@Override
public void onPictureTaken(byte[] data, Camera camera){
File pictureFile = getOutputMediaFile();
if(pictureFile == null){
Log.d("TEST", "Error creating media file, check storage permissions");
return;
}
try{
Log.d("TEST","File created");
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
}catch(FileNotFoundException e){
Log.d("TEST","File not found: "+e.getMessage());
} catch (IOException e){
Log.d("TEST","Error accessing file: "+e.getMessage());
}
}
};
private File getOutputMediaFile(){
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"MyCameraApp");
if(!mediaStorageDir.exists()){
if(!mediaStorageDir.mkdirs()){
return null;
}
}
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir.getPath()+File.separator+"IMG_"+timeStamp+".jpg");
return mediaFile;
}
@Override
protected Object doInBackground(Object[] params) {
try{
takePicture();
return "1";
}catch(Exception e){
return "-1";
}
}
@Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
releaseCamera();
}
}
并在我的mainActivity中调用它：
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
context = this;
CameraController cc = new CameraController(context);
cc.getCameraInstance();
cc.execute();
}
以上代码无效，无法拍摄任何照片。我调试了代码，发现没有调用 onPictureTaken 。
答案 0 :(得分：0)
尝试此代码：这是主要活动
public class AndroidCameraExample extends Activity implements SensorEventListener,FaceDetectionListener{
private Camera mCamera;
private CameraPreview mPreview;
private PictureCallback mPicture;
private Button capture, switchCamera;
private Context myContext;
private LinearLayout cameraPreview;
private boolean cameraFront = false,hasaccel,changed=false;
SensorManager sm;
List<Sensor> s;
Sensor sensor;
String photopath;
int ax=100,ay;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams layout = getWindow().getAttributes();
layout.screenBrightness = 1F;
getWindow().setAttributes(layout);
myContext = this;
initialize();
hasaccel = checkaccelerometer();
}
private int findFrontFacingCamera() {
int cameraId = -1;
// Search for the front facing camera
int numberOfCameras = Camera.getNumberOfCameras();
for (int i = 0; i < numberOfCameras; i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
cameraId = i;
cameraFront = true;
break;
}
}
return cameraId;
}
private int findBackFacingCamera() {
int cameraId = -1;
//Search for the back facing camera
//get the number of cameras
int numberOfCameras = Camera.getNumberOfCameras();
//for every camera check
for (int i = 0; i < numberOfCameras; i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
if (info.facing == CameraInfo.CAMERA_FACING_BACK) {
cameraId = i;
cameraFront = false;
break;
}
}
return cameraId;
}
public void onResume() {
super.onResume();
if (!hasCamera(myContext)) {
Toast toast = Toast.makeText(myContext, "Sorry, your phone does not have a camera!", Toast.LENGTH_LONG);
toast.show();
finish();
}
if (mCamera == null) {
//if the front facing camera does not exist
if (findFrontFacingCamera() < 0) {
Toast.makeText(this, "No front facing camera found.", Toast.LENGTH_LONG).show();
switchCamera.setVisibility(View.GONE);
}
int cameraId = findFrontFacingCamera();
//Mayur
mCamera = Camera.open((cameraId));
// mCamera.setFaceDetectionListener(this);
// mCamera.startFaceDetection();
setCameraDisplayOrientation(this, cameraId, mCamera);
mPicture = getPictureCallback();
mPreview.refreshCamera(mCamera);
}
}
public void initialize() {
cameraPreview = (LinearLayout) findViewById(R.id.camera_preview);
mPreview = new CameraPreview(myContext, mCamera);
cameraPreview.addView(mPreview);
capture = (Button) findViewById(R.id.button_capture);
capture.setOnClickListener(captrureListener);
switchCamera = (Button) findViewById(R.id.button_ChangeCamera);
switchCamera.setOnClickListener(switchCameraListener);
}
OnClickListener switchCameraListener = new OnClickListener() {
@Override
public void onClick(View v) {
//get the number of cameras
int camerasNumber = Camera.getNumberOfCameras();
if (camerasNumber > 1) {
//release the old camera instance
//switch camera, from the front and the back and vice versa
releaseCamera();
chooseCamera();
} else {
Toast toast = Toast.makeText(myContext, "Sorry, your phone has only one camera!", Toast.LENGTH_LONG);
toast.show();
}
}
};
public void chooseCamera() {
//if the camera preview is the front
if (cameraFront) {
int cameraId = findBackFacingCamera();
if (cameraId >= 0) {
//open the backFacingCamera
//set a picture callback
//refresh the preview
mCamera = Camera.open(cameraId);
mPicture = getPictureCallback();
mPreview.refreshCamera(mCamera);
}
} else {
int cameraId = findFrontFacingCamera();
if (cameraId >= 0) {
//open the backFacingCamera
//set a picture callback
//refresh the preview
mCamera = Camera.open(cameraId);
mPicture = getPictureCallback();
mPreview.refreshCamera(mCamera);
}
}
}
@Override
protected void onPause() {
super.onPause();
//when on Pause, release camera in order to be used from other applications
releaseCamera();
}
private boolean hasCamera(Context context) {
//check if the device has camera
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
return true;
} else {
return false;
}
}
private PictureCallback getPictureCallback() {
PictureCallback picture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
//make a new picture file
File pictureFile = getOutputMediaFile();
// Location of stored image
Log.d("Mayur", "Picture: "+pictureFile);
Log.d("Mayur","Data: "+data);
if (pictureFile == null) {
return;
}
try {
//check orientation and rotate if necessary
//write the file
while(!changed)
{
Log.d("Parth", "X: "+ax);
}
int rotate=-90;
/* if((ax<=5 && ax>=-1) && (ay>=6 && ay<=9))
{
rotate=-90;
}
else if((ax<=9 && ax>=6) && (ay>=-1 && ay<=5))
{
rotate=-90;
}
else if((ax<=-6 && ax>=-9) && (ay>=-1 && ay<=5))
{
rotate = -180;
}
else if((ax<=5 && ax>=-1) && (ay>=-9 && ay<=-6))
{
rotate = 90;
}
*/
Log.d("Parth", "X: "+ax+" Y:"+ay);
Matrix matrix = new Matrix();
if(android.os.Build.VERSION.SDK_INT>13 )
{
float[] mirrorY = { -1, 0, 0, 0, 1, 0, 0, 0, 1};
Matrix matrixMirrorY = new Matrix();
matrixMirrorY.setValues(mirrorY);
matrix.postConcat(matrixMirrorY);
matrix.preRotate(rotate);
}
Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
int i = ExifInterface.ORIENTATION_FLIP_HORIZONTAL;
bmp = Bitmap.createBitmap(bmp,0,0,bmp.getWidth(),bmp.getHeight(),matrix,true);
FileOutputStream fos = new FileOutputStream(pictureFile);
bmp.compress(Bitmap.CompressFormat.JPEG, 85, fos);
photopath = pictureFile.getAbsolutePath();
fos.flush();
fos.close();
bmp.recycle();
//Toast toast = Toast.makeText(myContext, "Picture saved: " + pictureFile.getName(), Toast.LENGTH_LONG);
//toast.show();
sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(pictureFile)));
Intent intent = new Intent(myContext, LayoutTest1Activity.class);
intent.putExtra("path", photopath);
startActivity(intent);
finish();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
//refresh camera to continue preview
mPreview.refreshCamera(mCamera);
}
};
return picture;
}
protected void checkorientation() {
// TODO Auto-generated method stub
sensor = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sm.registerListener(this, sensor,SensorManager.SENSOR_DELAY_FASTEST);
}
OnClickListener captrureListener = new OnClickListener() {
@Override
public void onClick(View v) {
//Mayur
checkorientation();
Camera.Parameters params=mCamera.getParameters();
List<Size> sizes =params.getSupportedPictureSizes();
Size mSize=null;
int temp=0;
// for(Size size:sizes)
// {
// mSize=size;
// Log.d("Mayur", "H: "+mSize.height+" W: "+mSize.width);
// }
mSize=sizes.get(0); //taking largest resolution
Log.d("Mayur", "Loaded with H: "+mSize.height+"W: "+mSize.width);
params.setPictureSize(mSize.width, mSize.height);
mCamera.setParameters(params);
//
mCamera.takePicture(null, null, mPicture);
}
};
private boolean checkaccelerometer() {
sm = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
s = new ArrayList<Sensor>();
s = sm.getSensorList(Sensor.TYPE_ACCELEROMETER);
if(s.size()>0)
{
Toast.makeText(myContext, "has accelerometer", Toast.LENGTH_SHORT).show();
return true;
}
return false;
// TODO Auto-generated method stub
}
//make picture and save to a folder
private static File getOutputMediaFile() {
//make a new file directory inside the "sdcard" folder
File mediaStorageDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/Creaa");
mediaStorageDir.mkdirs();
//if this "Creaa Camera folder does not exist
if (!mediaStorageDir.exists()) {
//if you cannot make this folder return
if (!mediaStorageDir.mkdirs()) {
return null;
}
}
//take the current timeStamp
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
//and make a media file:
mediaFile = new File(mediaStorageDir.getPath() + File.separator + "mypic_" + timeStamp + ".jpg");
return mediaFile;
}
private void releaseCamera() {
// stop and release camera
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
@Override
public void onSensorChanged(SensorEvent event) {
// TODO Auto-generated method stub
ax = (int) event.values[0];
ay = (int) event.values[1];
sm.unregisterListener(this);
Toast.makeText(myContext, "X : "+ax+" Y: "+ay, Toast.LENGTH_SHORT).show();
changed=true;
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
public static void setCameraDisplayOrientation(Activity activity,
int cameraId, android.hardware.Camera camera) {
android.hardware.Camera.CameraInfo info =
new android.hardware.Camera.CameraInfo();
android.hardware.Camera.getCameraInfo(cameraId, info);
int rotation = activity.getWindowManager().getDefaultDisplay()
.getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0: degrees = 0; break;
case Surface.ROTATION_90: degrees = 90; break;
case Surface.ROTATION_180: degrees = 180; break;
case Surface.ROTATION_270: degrees = 270; break;
}
int result;
if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
result = (info.orientation + degrees) % 360;
result = (360 - result) % 360; // compensate the mirror
} else { // back-facing
result = (info.orientation - degrees + 360) % 360;
}
Log.d("Parth", "Result : "+result);
camera.setDisplayOrientation(result);
}
@Override
public void onFaceDetection(Face[] faces, Camera camera) {
// TODO Auto-generated method stub
Toast.makeText(this, "facedeteted", Toast.LENGTH_SHORT).show();
if(faces.length>0)
Log.d("Parth", "mouth:"+faces[0].mouth.x+"\nrect :"+faces[0].rect.bottom);
}
}
和第二类：这是用于相机预览的，因为您需要从意图开始的前置摄像头逆视摄像头的surfaceview。
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
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) {
try {
// create the surface and start camera preview
if (mCamera == null) {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
}
} catch (IOException e) {
Log.d(VIEW_LOG_TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void refreshCamera(Camera camera) {
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
// start preview with new settings
setCamera(camera);
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e) {
Log.d(VIEW_LOG_TAG, "Error starting camera preview: " + e.getMessage());
}
}
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.
refreshCamera(mCamera);
}
public void setCamera(Camera camera) {
//method to set a camera instance
mCamera = camera;
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
// mCamera.release();
}
}
此代码用于直接启动前置摄像头。使用上面的两个类