Java tutorial
/* * Copyright (C) 2013 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 android.hardware.camera2; import android.annotation.IntDef; import android.util.AndroidException; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; /** * <p><code>CameraAccessException</code> is thrown if a camera device could not * be queried or opened by the {@link CameraManager}, or if the connection to an * opened {@link CameraDevice} is no longer valid.</p> * * @see CameraManager * @see CameraDevice */ public class CameraAccessException extends AndroidException { /** * The camera device is in use already. */ public static final int CAMERA_IN_USE = 4; /** * The system-wide limit for number of open cameras or camera resources has * been reached, and more camera devices cannot be opened or torch mode * cannot be turned on until previous instances are closed. */ public static final int MAX_CAMERAS_IN_USE = 5; /** * The camera is disabled due to a device policy, and cannot be opened. * * @see android.app.admin.DevicePolicyManager#setCameraDisabled(android.content.ComponentName, boolean) */ public static final int CAMERA_DISABLED = 1; /** * The camera device is removable and has been disconnected from the Android * device, or the camera id used with {@link android.hardware.camera2.CameraManager#openCamera} * is no longer valid, or the camera service has shut down the connection due to a * higher-priority access request for the camera device. */ public static final int CAMERA_DISCONNECTED = 2; /** * The camera device is currently in the error state. * * <p>The camera has failed to open or has failed at a later time * as a result of some non-user interaction. Refer to * {@link CameraDevice.StateCallback#onError} for the exact * nature of the error.</p> * * <p>No further calls to the camera will succeed. Clean up * the camera with {@link CameraDevice#close} and try * handling the error in order to successfully re-open the camera. * </p> * */ public static final int CAMERA_ERROR = 3; /** * A deprecated HAL version is in use. * @hide */ public static final int CAMERA_DEPRECATED_HAL = 1000; /** @hide */ @Retention(RetentionPolicy.SOURCE) @IntDef(prefix = { "CAMERA_", "MAX_CAMERAS_IN_USE" }, value = { CAMERA_IN_USE, MAX_CAMERAS_IN_USE, CAMERA_DISABLED, CAMERA_DISCONNECTED, CAMERA_ERROR }) public @interface AccessError { } // Make the eclipse warning about serializable exceptions go away private static final long serialVersionUID = 5630338637471475675L; // randomly generated private final int mReason; /** * The reason for the failure to access the camera. * * @see #CAMERA_DISABLED * @see #CAMERA_DISCONNECTED * @see #CAMERA_ERROR */ @AccessError public final int getReason() { return mReason; } public CameraAccessException(@AccessError int problem) { super(getDefaultMessage(problem)); mReason = problem; } public CameraAccessException(@AccessError int problem, String message) { super(getCombinedMessage(problem, message)); mReason = problem; } public CameraAccessException(@AccessError int problem, String message, Throwable cause) { super(getCombinedMessage(problem, message), cause); mReason = problem; } public CameraAccessException(@AccessError int problem, Throwable cause) { super(getDefaultMessage(problem), cause); mReason = problem; } /** * @hide */ public static String getDefaultMessage(@AccessError int problem) { switch (problem) { case CAMERA_IN_USE: return "The camera device is in use already"; case MAX_CAMERAS_IN_USE: return "The system-wide limit for number of open cameras has been reached, " + "and more camera devices cannot be opened until previous instances " + "are closed."; case CAMERA_DISCONNECTED: return "The camera device is removable and has been disconnected from the " + "Android device, or the camera service has shut down the connection due " + "to a higher-priority access request for the camera device."; case CAMERA_DISABLED: return "The camera is disabled due to a device policy, and cannot be opened."; case CAMERA_ERROR: return "The camera device is currently in the error state; " + "no further calls to it will succeed."; } return null; } private static String getCombinedMessage(@AccessError int problem, String message) { String problemString = getProblemString(problem); return String.format("%s (%d): %s", problemString, problem, message); } private static String getProblemString(int problem) { String problemString; switch (problem) { case CAMERA_IN_USE: problemString = "CAMERA_IN_USE"; break; case MAX_CAMERAS_IN_USE: problemString = "MAX_CAMERAS_IN_USE"; break; case CAMERA_DISCONNECTED: problemString = "CAMERA_DISCONNECTED"; break; case CAMERA_DISABLED: problemString = "CAMERA_DISABLED"; break; case CAMERA_ERROR: problemString = "CAMERA_ERROR"; break; case CAMERA_DEPRECATED_HAL: problemString = "CAMERA_DEPRECATED_HAL"; break; default: problemString = "<UNKNOWN ERROR>"; } return problemString; } }