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Improved the CameraThread state machine, and fixed a bug where preview would not continue after capture.

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git-svn-id: https://zxing.googlecode.com/svn/trunk@353 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
dswitkin 2008-04-08 16:06:13 +00:00
parent e9ed806d30
commit d9fc77b9e2
1 changed files with 33 additions and 23 deletions
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56
android-m3/src/com/google/zxing/client/android/CameraThread.java
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@ -34,8 +34,14 @@ final class CameraThread extends Thread {
private final CameraSurfaceView surfaceView;
private final Handler activityHandler;
private final DecodeThread decodeThread;
private boolean requestDecode;
private boolean suspendPreview;
private State state;
private enum State {
PREVIEW,
DECODE,
SAVE,
DONE
}
CameraThread(BarcodeReaderCaptureActivity activity, CameraSurfaceView surfaceView,
CameraManager cameraManager, Handler activityHandler) {
@ -44,8 +50,7 @@ final class CameraThread extends Thread {
decodeThread = new DecodeThread(activity, cameraManager);
decodeThread.start();
requestDecode = true;
suspendPreview = false;
state = State.DONE;
}
@Override
@ -55,37 +60,38 @@ final class CameraThread extends Thread {
public void handleMessage(Message message) {
switch (message.what) {
case R.id.preview:
if (!suspendPreview) {
if (state == State.PREVIEW) {
surfaceView.capturePreviewAndDraw();
}
break;
case R.id.save:
suspendPreview = true;
state = State.SAVE;
Message save = Message.obtain(decodeThread.handler, R.id.save);
save.sendToTarget();
break;
case R.id.restart_preview:
restartPreviewAndDecode();
return;
break;
case R.id.quit:
state = State.DONE;
Message quit = Message.obtain(decodeThread.handler, R.id.quit);
quit.sendToTarget();
Looper.myLooper().quit();
break;
case R.id.decode_started:
// Since the decoder is done with the camera, continue fetching preview frames.
suspendPreview = false;
state = State.PREVIEW;
break;
case R.id.decode_succeeded:
state = State.DONE;
// Message.copyFrom() did not work as expected, hence this workaround.
Message success = Message.obtain(activityHandler, R.id.decode_succeeded, message.obj);
success.arg1 = message.arg1;
success.sendToTarget();
suspendPreview = true;
break;
case R.id.decode_failed:
// We're decoding as fast as possible, so when one fails, start another.
requestDecode = true;
startDecode();
break;
case R.id.save_succeeded:
// TODO: Put up a non-blocking status message
@ -94,15 +100,10 @@ final class CameraThread extends Thread {
case R.id.save_failed:
// TODO: Put up a blocking error message
restartPreviewAndDecode();
return;
break;
}
if (requestDecode) {
requestDecode = false;
suspendPreview = true;
Message decode = Message.obtain(decodeThread.handler, R.id.decode);
decode.sendToTarget();
} else if (!suspendPreview) {
if (state == State.PREVIEW) {
Message preview = Message.obtain(handler, R.id.preview);
preview.sendToTarget();
}
@ -111,8 +112,7 @@ final class CameraThread extends Thread {
decodeThread.setCameraThreadHandler(handler);
// Start ourselves capturing previews
Message preview = Message.obtain(handler, R.id.preview);
preview.sendToTarget();
restartPreviewAndDecode();
Looper.loop();
}
@ -131,14 +131,24 @@ final class CameraThread extends Thread {
message.sendToTarget();
}
/**
* Start a decode if possible, but not now if the DecodeThread is in the middle of saving.
*/
private void startDecode() {
if (state != State.SAVE) {
state = State.DECODE;
Message decode = Message.obtain(decodeThread.handler, R.id.decode);
decode.sendToTarget();
}
}
/**
* Take one preview to update the screen, then do a decode and continue previews.
*/
private void restartPreviewAndDecode() {
requestDecode = true;
suspendPreview = false;
Message preview = Message.obtain(handler, R.id.preview);
preview.sendToTarget();
state = State.PREVIEW;
surfaceView.capturePreviewAndDraw();
startDecode();
}
}