以下课程将使用前置摄像头拍摄照片并将其存储在Android画廊中：
public class TakePicture extends Activity implements SurfaceHolder.Callback {
// a variable to store a reference to the Image View at the main.xml file
// private ImageView iv_image;
// a variable to store a reference to the Surface View at the main.xml file
private SurfaceView sv;
// a bitmap to display the captured image
private Bitmap bmp;
FileOutputStream fo;
// Camera variables
// a surface holder
private SurfaceHolder sHolder;
// a variable to control the camera
private Camera mCamera;
// the camera parameters
private Camera.Parameters parameters;
private String FLASH_MODE;
private boolean isFrontCamRequest = false;
private Camera.Size pictureSize;
/** Called when the activity is first created. */
@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.background);
// check if this device has a camera
// get the Image View at the main.xml file
// iv_image = (ImageView) findViewById(R.id.imageView);
// get the Surface View at the main.xml file
Bundle extras = getIntent().getExtras();
FLASH_MODE = "FLASH_MODE_OFF";
boolean front_cam_req = true;
isFrontCamRequest = front_cam_req;
sv = (SurfaceView) findViewById(R.id.camera_preview);
// Get a surface
sHolder = sv.getHolder();
// add the callback interface methods defined below as the Surface
// View
// callbacks
sHolder.addCallback(this);
// tells Android that this surface will have its data constantly
// replaced
if (Build.VERSION.SDK_INT < 11)
sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/** Check if this device has front camera */
private boolean checkFrontCamera(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA_FRONT)) {
// this device has front camera
return true;
} else {
// no front camera on this device
return false;
}
}
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
// get camera parameters
if (mCamera != null) {
parameters = mCamera.getParameters();
if (FLASH_MODE == null || FLASH_MODE.isEmpty()) {
FLASH_MODE = "auto";
}
parameters.setFlashMode(FLASH_MODE);
pictureSize = getBiggesttPictureSize(parameters);
if (pictureSize != null)
parameters
.setPictureSize(pictureSize.width, pictureSize.height);
// set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
// sets what code should be executed after the picture is taken
Camera.PictureCallback mCall = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// decode the data obtained by the camera into a Bitmap
Log.d("ImageTakin", "Done");
bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
if (bmp != null)
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
//FOR GALLERY STORAGE ---- TEST
File androidVidGalleryPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File imagesFolder = new File(androidVidGalleryPath+"/Guardian");
if (!imagesFolder.exists())
imagesFolder.mkdirs(); // <----
SharedPreferences pref = getSharedPreferences("MyPref", Context.MODE_PRIVATE);
final SharedPreferences.Editor editor = pref.edit();
Integer guardianCount = pref.getInt("guardianCountimg",0);
File image = new File(androidVidGalleryPath+"/Guardian/img_"+String.valueOf(guardianCount)+".jpg");
editor.putInt("guardianCountimg",guardianCount+1).commit();
// write the bytes in file
try {
fo = new FileOutputStream(image);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
}
try {
fo.write(bytes.toByteArray());
} catch (IOException e) {
// TODO Auto-generated catch block
}
// remember close de FileOutput
try {
fo.close();
//sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://"
// + Environment
// .getExternalStorageDirectory())));
sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(image)));
} catch (IOException e) {
// TODO Auto-generated catch block
}
if (mCamera != null) {
mCamera.stopPreview();
// release the camera
mCamera.release();
}
Toast.makeText(getApplicationContext(),
"Invalid login\n\nRegistered owner will be notified!", Toast.LENGTH_LONG)
.show();
if (bmp != null) {
bmp.recycle();
bmp = null;
System.gc();
}
TakePicture.this.finish();
}
};
mCamera.takePicture(null, null, mCall);
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw the preview.
if (isFrontCamRequest) {
// set flash 0ff
FLASH_MODE = "off";
// only for gingerbread and newer versions
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD) {
mCamera = openFrontFacingCameraGingerbread();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera = null;
Toast.makeText(getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
TakePicture.this.finish();
}
} else {
if (checkFrontCamera(getApplicationContext())) {
mCamera = openFrontFacingCameraGingerbread();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera = null;
Toast.makeText(getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
TakePicture.this.finish();
}
}/*
* else { // API dosen't support front camera or no front camera
* Log.d("Camera",
* "API dosen't support front camera or no front camera");
* Toast.makeText( getApplicationContext(),
* "API dosen't support front camera or no front camera",
* Toast.LENGTH_LONG).show();
*
* finish(); }
*/
}
} else {
mCamera = getCameraInstance();
try {
mCamera.setPreviewDisplay(holder);
} catch (Exception exception) {
mCamera = null;
}
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// stop the preview
/*
* mCamera.stopPreview(); // release the camera mCamera.release();
*/
// unbind the camera from this object
mCamera = null;
}
private Camera openFrontFacingCameraGingerbread() {
int cameraCount = 0;
Camera cam = null;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();
for (int camIdx = 0; camIdx < cameraCount; camIdx++) {
Camera.getCameraInfo(camIdx, cameraInfo);
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
try {
cam = Camera.open(camIdx);
} catch (RuntimeException e) {
Log.e("Camera",
"Camera failed to open: " + e.getLocalizedMessage());
Toast.makeText(getApplicationContext(),
"Front Camera failed to open", Toast.LENGTH_LONG)
.show();
}
}
}
return cam;
}
@Override
protected void onDestroy() {
Intent intent = new Intent("custom-event-name");
// You can also include some extra data.
intent.putExtra("message", "This is my message!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
super.onDestroy();
}
private Camera.Size getBiggesttPictureSize(Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
return (result);
}
}
问题是我想这样做而不必使用以下方式开始新活动：
Intent intent = new Intent(MainActivity.this,TakePicture.class);
startActivity(intent);
相反，我已经在on create部分将此活动的代码添加到名为takePic（）的方法中，并移动了所需的方法，如下所示：
public void takePic(){
FLASH_MODE = "FLASH_MODE_OFF";
boolean front_cam_req = true;
isFrontCamRequest = front_cam_req;
sv = (SurfaceView) findViewById(R.id.camera_preview);
sHolder = sv.getHolder();
sHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw the preview.
if (isFrontCamRequest) {
// set flash 0ff
FLASH_MODE = "off";
// only for gingerbread and newer versions
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD) {
mCamera = openFrontFacingCameraGingerbread();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera = null;
Toast.makeText(getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
//TakePicture.this.finish();
}
} else {
if (checkFrontCamera(getApplicationContext())) {
mCamera = openFrontFacingCameraGingerbread();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera = null;
Toast.makeText(getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
//TakePicture.this.finish();
}
}/*
* else { // API dosen't support front camera or no front camera
* Log.d("Camera",
* "API dosen't support front camera or no front camera");
* Toast.makeText( getApplicationContext(),
* "API dosen't support front camera or no front camera",
* Toast.LENGTH_LONG).show();
*
* finish(); }
*/
}
} else {
mCamera = getCameraInstance();
try {
mCamera.setPreviewDisplay(holder);
} catch (Exception exception) {
mCamera = null;
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// get camera parameters
if (mCamera != null) {
parameters = mCamera.getParameters();
if (FLASH_MODE == null || FLASH_MODE.isEmpty()) {
FLASH_MODE = "auto";
}
parameters.setFlashMode(FLASH_MODE);
pictureSize = getBiggesttPictureSize(parameters);
if (pictureSize != null)
parameters
.setPictureSize(pictureSize.width, pictureSize.height);
// set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
// sets what code should be executed after the picture is taken
Camera.PictureCallback mCall = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// decode the data obtained by the camera into a Bitmap
Log.d("ImageTakin", "Done");
bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
if (bmp != null)
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
//FOR GALLERY STORAGE ---- TEST
File androidVidGalleryPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File imagesFolder = new File(androidVidGalleryPath+"/Guardian");
if (!imagesFolder.exists())
imagesFolder.mkdirs(); // <----
SharedPreferences pref = getSharedPreferences("MyPref", Context.MODE_PRIVATE);
final SharedPreferences.Editor editor = pref.edit();
Integer guardianCount = pref.getInt("guardianCountimg",0);
File image = new File(androidVidGalleryPath+"/Guardian/img_"+String.valueOf(guardianCount)+".jpg");
editor.putInt("guardianCountimg",guardianCount+1).commit();
// write the bytes in file
try {
fo = new FileOutputStream(image);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
}
try {
fo.write(bytes.toByteArray());
} catch (IOException e) {
// TODO Auto-generated catch block
}
// remember close de FileOutput
try {
fo.close();
//sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://"
// + Environment
// .getExternalStorageDirectory())));
sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(image)));
} catch (IOException e) {
// TODO Auto-generated catch block
}
if (mCamera != null) {
mCamera.stopPreview();
// release the camera
mCamera.release();
}
Toast.makeText(getApplicationContext(),
"Invalid login\n\nRegistered owner will be notified!", Toast.LENGTH_LONG)
.show();
if (bmp != null) {
bmp.recycle();
bmp = null;
System.gc();
}
//TakePicture.this.finish();
}
};
mCamera.takePicture(null, null, mCall);
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
mCamera = null;
}
});
// tells Android that this surface will have its data constantly
// replaced
if (Build.VERSION.SDK_INT < 11)
sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/** Check if this device has front camera */
private boolean checkFrontCamera(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA_FRONT)) {
// this device has front camera
return true;
} else {
// no front camera on this device
return false;
}
}
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
private Camera openFrontFacingCameraGingerbread() {
int cameraCount = 0;
Camera cam = null;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();
for (int camIdx = 0; camIdx < cameraCount; camIdx++) {
Camera.getCameraInfo(camIdx, cameraInfo);
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
try {
cam = Camera.open(camIdx);
} catch (RuntimeException e) {
Log.e("Camera",
"Camera failed to open: " + e.getLocalizedMessage());
Toast.makeText(getApplicationContext(),
"Front Camera failed to open", Toast.LENGTH_LONG)
.show();
}
}
}
return cam;
}
@Override
protected void onDestroy() {
Intent intent = new Intent("custom-event-name");
// You can also include some extra data.
intent.putExtra("message", "This is my message!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
super.onDestroy();
}
private Camera.Size getBiggesttPictureSize(Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
return (result);
}
使用takePic（）方法时，在我返回主屏幕并重新打开应用程序之前不会拍照。
为什么我打电话给takePic（）时没有拍到照片？
答案 0 :(得分：0)
SurfaceView的Surface是在onCreate()完成后的某个时间异步创建的。您的takePic()方法正在建立回调，但如果在创建Surface之后这样做，那么回调将不会被调用，直到下次创建Surface时（例如旋转设备时） ）。
将捕获绑定到预览表面创建回调似乎有点落后，特别是在SurfaceView的quirky nature时。