Android闪关灯打开与关闭问题

在项目中需要做个类似手电筒的功能。但是测试时出现了多款手机打不开闪光灯的情况，很奇怪。后来就发现是在Android5.0以后和5.0之前是不一样的。这里有一个 工具 类，可以直接拿到项目中使用。

public class LightManager {
 private static final String TAG = LightManager.class.getName();
 
 /**
 * 上下文对象
 */
 private Context context;
 
 /**
 * 是否已经开启闪光灯
 */
 private boolean isOpenFlash = false;
 
 /**
 * Camera相机硬件操作类
 */
 private Camera camera = null;
 
 /**
 * Camera2相机硬件操作类
 */
 private CameraManager manager = null;
 private CameraDevice cameraDevice;
 private CameraCaptureSession captureSession = null;
 private CaptureRequest request = null;
 private SurfaceTexture surfaceTexture;
 private Surface surface;
 private String cameraId = null;
 private boolean isSupportFlashCamera2 = false;
 
 private LightManager() {
 }
 
 public LightManager(Context context) {
 this.context = context;
 }
 
 /**
 * 初始化相机
 */
 public void init() {
 this.manager = (CameraManager) context.getSystemService(Context.CAMERA_SERVICE);
 if (isLOLLIPOP()) {
 initCamera2();
 } else {
 if (camera == null) {
 camera = Camera.open();
 }
 }
 }
 
 /**
 * 开启闪光灯
 */
 public void turnOn() {
 if (!isSupportFlash()) {
 showToast("设备不支持闪光灯！");
 return;
 }
 if (ActivityCompat.checkSelfPermission(context, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
 showToast("应用未开启访问相机权限！");
 return;
 }
 if (isOpenFlash) {
 return;
 }
 
 if (isLOLLIPOP()) {
 turnLightOnCamera2();
 } else {
 turnLightOnCamera(camera);
 }
 }
 
 /**
 * 关闭闪光灯
 */
 public void turnOff() {
 if (!isSupportFlash()) {
 showToast("设备不支持闪光灯！");
 return;
 }
 if (ActivityCompat.checkSelfPermission(context, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
 showToast("应用未开启访问相机权限！");
 return;
 }
 if (!isOpenFlash) {
 return;
 }
 if (isLOLLIPOP()) {
 turnLightOffCamera2();
 } else {
 turnLightOffCamera(camera);
 }
 isOpenFlash = false;
 }
 
 /**
 * 开启Camera2闪光灯
 */
 private void turnLightOnCamera2() {
 new Object() {
 private void _turnLightOnCamera2() {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 if (ActivityCompat.checkSelfPermission(context, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
 showToast("应用未开启访问相机权限！");
 return;
 }
 try {
 manager.openCamera(cameraId, new CameraDevice.StateCallback() {
 
 @Override
 public void onOpened(CameraDevice camera) {
 cameraDevice = camera;
 createCaptureSession();
 }
 
 @Override
 public void onError(CameraDevice camera, int error) {
 }
 
 @Override
 public void onDisconnected(CameraDevice camera) {
 }
 }, null);
 } catch (Exception e) {
 showToast("开启失败：" + e.getMessage());
 }
 }
 }
 }._turnLightOnCamera2();
 }
 
 /**
 * 关闭Camera2闪光灯
 */
 private void turnLightOffCamera2() {
 new Object() {
 private void _turnLightOffCamera2() {
 if (cameraDevice != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 cameraDevice.close();
 }
 }
 }._turnLightOffCamera2();
 }
 
 /**
 * 判断设备是否支持闪光灯
 */
 public boolean isSupportFlash() {
 if (isLOLLIPOP()) {
 return isSupportFlashCamera2;
 } else {
 PackageManager pm = context.getPackageManager();
 FeatureInfo[] features = pm.getSystemAvailableFeatures();
 for (FeatureInfo f : features) {
 // 判断设备是否支持闪光灯
 if (PackageManager.FEATURE_CAMERA_FLASH.equals(f.name)) {
 return true;
 }
 }
  
 }
 return false;
 }
 
 /**
 * 是否已经开启闪光灯
 */
 public boolean isTurnOnFlash() {
 return isOpenFlash;
 }
 
 /**
 * 判断Android系统版本是否 >= LOLLIPOP(API21)
 */
 private boolean isLOLLIPOP() {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 return true;
 } else {
 return false;
 }
 }
 
 /**
 * 通过设置Camera打开闪光灯
 */
 public void turnLightOnCamera(Camera mCamera) {
 mCamera.startPreview();
 Camera.Parameters parameters = mCamera.getParameters();
 List<String> flashModes = parameters.getSupportedFlashModes();
 String flashMode = parameters.getFlashMode();
 if (!Camera.Parameters.FLASH_MODE_TORCH.equals(flashMode)) {
 // 开启闪光灯
 if (flashModes.contains(Camera.Parameters.FLASH_MODE_TORCH)) {
 parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
 mCamera.setParameters(parameters);
 }
 }
 isOpenFlash = true;
 }
 
 /**
 * 通过设置Camera关闭闪光灯
 */
 public void turnLightOffCamera(Camera mCamera) {
 mCamera.stopPreview();
 Camera.Parameters parameters = mCamera.getParameters();
 List<String> flashModes = parameters.getSupportedFlashModes();
 String flashMode = parameters.getFlashMode();
 if (!Camera.Parameters.FLASH_MODE_OFF.equals(flashMode)) {
 // 关闭闪光灯
 if (flashModes.contains(Camera.Parameters.FLASH_MODE_OFF)) {
 parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
 mCamera.setParameters(parameters);
 }
 }
 isOpenFlash = false;
 camera.release();
 camera = null;
 }
 
 /**
 * 初始化Camera2
 */
 private void initCamera2() {
 new Object() {
 private void _initCamera2() {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 try {
 for (String _cameraId : manager.getCameraIdList()) {
 CameraCharacteristics characteristics = manager.getCameraCharacteristics(_cameraId);
 // 过滤掉前置摄像头
 Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
 if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
 continue;
 }
 StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
 if (map == null) {
 continue;
 }
 cameraId = _cameraId;
 // 判断设备是否支持闪光灯
 isSupportFlashCamera2 = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
 }
 } catch (Exception e) {
 showToast("初始化失败：" + e.getMessage());
 }
 }
 }
 }._initCamera2();
 }
 
 /**
 * createCaptureSession
 */
 private void createCaptureSession() {
 new Object() {
 private void createCaptureSession() {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 final CameraCaptureSession.StateCallback stateCallback = new CameraCaptureSession.StateCallback() {
 
 public void onConfigured(CameraCaptureSession arg0) {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
 captureSession = arg0;
 CaptureRequest.Builder builder;
 try {
 builder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
 builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_TORCH);
 builder.addTarget(surface);
 request = builder.build();
 captureSession.capture(request, null, null);
 isOpenFlash = true;
 } catch (Exception e) {
 showToast("开启失败：" + e.getMessage());
 }
 }
 }
 
 public void onConfigureFailed(CameraCaptureSession arg0) {
 }
 };
 
 surfaceTexture = new SurfaceTexture(0, false);
 surfaceTexture.setDefaultBufferSize(1280, 720);
 surface = new Surface(surfaceTexture);
 ArrayList localArrayList = new ArrayList(1);
 localArrayList.add(surface);
 try {
 cameraDevice.createCaptureSession(localArrayList, stateCallback, null);
 } catch (Exception e) {
 showToast("开启失败：" + e.getMessage());
 }
 }
 }
 }._createCaptureSession();
 }
 
 private void showToast(String content) {
 Toast.makeText(context, content, Toast.LENGTH_LONG).show();
 }
 
}

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