Android OnPictureTaken（）定时/保存问题
我正在创建一个自定义相机应用程序（将包含在一个更大的主应用程序中），该应用程序加载带有相机的视图-预览和图片库预览-以便用户可以拍摄一张照片或选择一张先前存在的照片。如果用户确实拍了一张照片，我只想显示一个确认对话框，如果确认了，将控制权传递回主活动。我无法存储照片：需要快速将其用作附件，一旦通过主活动发送，请将其处理掉 当我拍摄一张照片并调用onPictureTaken（）时，问题就出现了：它要么不工作，要么保存一张照片需要花费相当长的时间。此外，我似乎不知道如何在不将照片保存到目录的情况下当场提取照片；我计划立即删除目录，但必须有一种更干净的方法（本质上，我只想访问原始字节数组，而不必保存它） 我希望它是模块化的（在我接下来的项目中会大量使用相机），我认为这是增加整体滞后的原因 我遵循了谷歌的开发者Android，我的大部分代码都是从这里的示例中派生出来的 我也在用ActionBarSherlock 我目前有三门课： CameraManagerAndroid OnPictureTaken（）定时/保存问题,android,camera,Android,Camera,我正在创建一个自定义相机应用程序（将包含在一个更大的主应用程序中），该应用程序加载带有相机的视图-预览和图片库预览-以便用户可以拍摄一张照片或选择一张先前存在的照片。如果用户确实拍了一张照片，我只想显示一个确认对话框，如果确认了，将控制权传递回主活动。我无法存储照片：需要快速将其用作附件，一旦通过主活动发送，请将其处理掉 当我拍摄一张照片并调用onPictureTaken（）时，问题就出现了：它要么不工作，要么保存一张照片需要花费相当长的时间。此外，我似乎不知道如何在不将照片保存到目录的情况下当
public class CameraManager {
private static Camera CAMERA;
/** Check if this device has a camera */
public static boolean doesDeviceHaveCamera(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
return true;
}
else {
return false;
}
}
public static Camera getCameraInstance(){
CAMERA = null;
try {
CAMERA = Camera.open();
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return CAMERA;
}
}
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "CameraPreview";
private SurfaceHolder surfaceHolder;
private Camera camera;
public CameraPreview(Context context, Camera camera) {
super(context);
this.camera = camera;
surfaceHolder = getHolder();
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); // deprecated setting, but required on Android versions prior to 3.0
}
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
}
catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
camera.stopPreview();
camera.release();
}
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 (surfaceHolder.getSurface() == null){
return;
}
try {
camera.stopPreview();
}
catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
camera.setDisplayOrientation(90);
// start preview with new settings
try {
camera.setPreviewDisplay(surfaceHolder);
camera.startPreview();
}
catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
public class CameraActivity extends SherlockActivity {
private static final String TAG = "CameraActivity";
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
private Camera camera;
private CameraPreview preview;
private PictureCallback picture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: media file is null.");
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
}
catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
}
catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().hide();
setContentView(R.layout.camera_view);
/**Get a camera instance**/
if(CameraManager.doesDeviceHaveCamera(this)){
camera = CameraManager.getCameraInstance();
}
else{
return;
}
/**Create a SurfaceView preview (holds the camera feed) and set it to the corresponding XML layout**/
preview = new CameraPreview(this, camera);
FrameLayout previewContainer = (FrameLayout) findViewById(R.id.camera_preview);
previewContainer.addView(preview);
/**Set up a capture button, which takes the picture**/
Button captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
camera.takePicture(null, null, picture);
}
});
}
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyDirectory");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("MyDirectory", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
}
else if(type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
}
else {
return null;
}
return mediaFile;
}
}
nullpictureTaken（）onClick（）camera.takePicture（）这仍然不是一个灵丹妙药：您可能希望将写入文件卸载到另一个工作线程，以便让相机拍摄下一张照片。如上所述，如果您只需要实时访问原始字节数组，请不要写入文件。因此我应该在主活动（调用CameraActivity的活动）中的异步任务上启动CameraActivity。@yoaquim:我不知道“调用CameraActivity”是什么意思。如果您的意思是
startActivity（）startActivity（）