CameraCaptureCallbacks.java
/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.camera.core.impl;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* Different implementations of {@link CameraCaptureCallback}.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public final class CameraCaptureCallbacks {
private CameraCaptureCallbacks() {
}
/** Returns a camera capture callback which does nothing. */
@NonNull
public static CameraCaptureCallback createNoOpCallback() {
return new NoOpCameraCaptureCallback();
}
/** Returns a camera capture callback which calls a list of other callbacks. */
@NonNull
static CameraCaptureCallback createComboCallback(
@NonNull List<CameraCaptureCallback> callbacks) {
if (callbacks.isEmpty()) {
return createNoOpCallback();
} else if (callbacks.size() == 1) {
return callbacks.get(0);
}
return new ComboCameraCaptureCallback(callbacks);
}
/** Returns a camera capture callback which calls a list of other callbacks. */
@NonNull
public static CameraCaptureCallback createComboCallback(
@NonNull CameraCaptureCallback... callbacks) {
return createComboCallback(Arrays.asList(callbacks));
}
static final class NoOpCameraCaptureCallback extends CameraCaptureCallback {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureResult cameraCaptureResult) {
}
@Override
public void onCaptureFailed(@NonNull CameraCaptureFailure failure) {
}
}
/**
* A CameraCaptureCallback which contains a list of CameraCaptureCallback and will propagate
* received callback to the list.
*/
public static final class ComboCameraCaptureCallback extends CameraCaptureCallback {
private final List<CameraCaptureCallback> mCallbacks = new ArrayList<>();
ComboCameraCaptureCallback(@NonNull List<CameraCaptureCallback> callbacks) {
for (CameraCaptureCallback callback : callbacks) {
// A no-op callback doesn't do anything, so avoid adding it to the final list.
if (!(callback instanceof NoOpCameraCaptureCallback)) {
mCallbacks.add(callback);
}
}
}
@Override
public void onCaptureCompleted(@NonNull CameraCaptureResult cameraCaptureResult) {
for (CameraCaptureCallback callback : mCallbacks) {
callback.onCaptureCompleted(cameraCaptureResult);
}
}
@Override
public void onCaptureFailed(@NonNull CameraCaptureFailure failure) {
for (CameraCaptureCallback callback : mCallbacks) {
callback.onCaptureFailed(failure);
}
}
@Override
public void onCaptureCancelled() {
for (CameraCaptureCallback callback : mCallbacks) {
callback.onCaptureCancelled();
}
}
@NonNull
public List<CameraCaptureCallback> getCallbacks() {
return mCallbacks;
}
}
}