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Rewrite auto-focus loop to be more robust, like continuing even if camera driver errors

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This commit is contained in:
Sean Owen 2014-02-09 11:10:01 -05:00
parent 091e614c20
commit b8fc4ebf16
1 changed files with 40 additions and 20 deletions
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48
android/src/com/google/zxing/client/android/camera/AutoFocusManager.java
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@ -25,6 +25,7 @@ import android.util.Log;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.Collection; import java.util.Collection;
import java.util.concurrent.RejectedExecutionException;
import com.google.zxing.client.android.PreferencesActivity; import com.google.zxing.client.android.PreferencesActivity;
@ -40,7 +41,8 @@ final class AutoFocusManager implements Camera.AutoFocusCallback {
FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO); FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO);
} }
private boolean active; private boolean stopped;
private boolean focusing;
private final boolean useAutoFocus; private final boolean useAutoFocus;
private final Camera camera; private final Camera camera;
private AsyncTask<?,?,?> outstandingTask; private AsyncTask<?,?,?> outstandingTask;
@ -58,26 +60,53 @@ final class AutoFocusManager implements Camera.AutoFocusCallback {
@Override @Override
public synchronized void onAutoFocus(boolean success, Camera theCamera) { public synchronized void onAutoFocus(boolean success, Camera theCamera) {
if (active) { focusing = false;
outstandingTask = new AutoFocusTask(); autoFocusAgainLater();
outstandingTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR); }
private void autoFocusAgainLater() {
if (!stopped && outstandingTask == null) {
AutoFocusTask newTask = new AutoFocusTask();
try {
newTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
outstandingTask = newTask;
} catch (RejectedExecutionException ree) {
Log.w(TAG, "Could not request auto focus", ree);
}
} }
} }
synchronized void start() { synchronized void start() {
if (useAutoFocus) { if (useAutoFocus) {
active = true; cancelOutstandingTask();
if (!stopped && !focusing) {
try { try {
camera.autoFocus(this); camera.autoFocus(this);
focusing = true;
} catch (RuntimeException re) { } catch (RuntimeException re) {
// Have heard RuntimeException reported in Android 4.0.x+; continue? // Have heard RuntimeException reported in Android 4.0.x+; continue?
Log.w(TAG, "Unexpected exception while focusing", re); Log.w(TAG, "Unexpected exception while focusing", re);
// Try again later to keep cycle going
autoFocusAgainLater();
}
} }
} }
} }
private void cancelOutstandingTask() {
if (outstandingTask != null) {
if (outstandingTask.getStatus() != AsyncTask.Status.FINISHED) {
outstandingTask.cancel(true);
}
outstandingTask = null;
}
}
synchronized void stop() { synchronized void stop() {
stopped = true;
if (useAutoFocus) { if (useAutoFocus) {
cancelOutstandingTask();
// Doesn't hurt to call this even if not focusing
try { try {
camera.cancelAutoFocus(); camera.cancelAutoFocus();
} catch (RuntimeException re) { } catch (RuntimeException re) {
@ -85,11 +114,6 @@ final class AutoFocusManager implements Camera.AutoFocusCallback {
Log.w(TAG, "Unexpected exception while cancelling focusing", re); Log.w(TAG, "Unexpected exception while cancelling focusing", re);
} }
} }
if (outstandingTask != null) {
outstandingTask.cancel(true);
outstandingTask = null;
}
active = false;
} }
private final class AutoFocusTask extends AsyncTask<Object,Object,Object> { private final class AutoFocusTask extends AsyncTask<Object,Object,Object> {
@ -100,11 +124,7 @@ final class AutoFocusManager implements Camera.AutoFocusCallback {
} catch (InterruptedException e) { } catch (InterruptedException e) {
// continue // continue
} }
synchronized (AutoFocusManager.this) {
if (active) {
start(); start();
}
}
return null; return null;
} }
} }