以前不知道有个系统属性可以做，后面的代码我几乎都用系统属性来写，比写个额外的广播接口方便多了。

实现一个相机的开关接口给上层调用，也就是打开后，上层无法再调用相机，关闭后可以正常打开，无需重启，直接贴代码

diff --git a/core/java/android/hardware/Camera.java b/core/java/android/hardware/Camera.java
index f6697134bfa6..eee994271221 100644
--- a/core/java/android/hardware/Camera.java
+++ b/core/java/android/hardware/Camera.java
@@ -51,6 +51,7 @@ import android.util.Log;import android.view.Surface;import android.view.SurfaceHolder;+import android.os.SystemProperties;//add LQXimport com.android.internal.R;import com.android.internal.annotations.GuardedBy;import com.android.internal.app.IAppOpsCallback;
@@ -396,6 +397,13 @@ public class Camera {* @see android.app.admin.DevicePolicyManager#getCameraDisabled(android.content.ComponentName)*/public static Camera open(int cameraId) {
+
+        // LQX
+        if(SystemProperties.get("persist.sys.disablecamera").equals("true")){
+            Log.d(TAG, "camera sensor is close" + "LQX");
+            return null;
+        }
+        // LQXreturn new Camera(cameraId);}@@ -409,6 +417,12 @@ public class Camera {* @see #open(int)*/public static Camera open() {
+        //add
+        if(SystemProperties.get("persist.sys.disablecamera").equals("true")){
+            Log.d(TAG, "camera sensor is close" + "LQX");
+            return null;
+        }
+        // endint numberOfCameras = getNumberOfCameras();CameraInfo cameraInfo = new CameraInfo();for (int i = 0; i < numberOfCameras; i++) {
@@ -463,7 +477,12 @@ public class Camera {if (halVersion < CAMERA_HAL_API_VERSION_3_0) {throw new IllegalArgumentException("Unsupported HAL version " + halVersion);}
-
+        // add
+        if(SystemProperties.get("persist.sys.disablecamera").equals("true")){
+            Log.d(TAG, "camera sensor is close" + "LQX");
+            return null;
+        }
+        // endreturn new Camera(cameraId);}@@ -532,6 +551,12 @@ public class Camera {* @hide*/public static Camera openUninitialized() {
+        // add
+        if(SystemProperties.get("persist.sys.disablecamera").equals("true")){
+            Log.d(TAG, "camera sensor is close" + "LQX");
+            return null;
+        }
+        //endreturn new Camera();}diff --git a/core/java/android/hardware/camera2/CameraManager.java b/core/java/android/hardware/camera2/CameraManager.java
index 56592ab43143..d885894dd106 100644
--- a/core/java/android/hardware/camera2/CameraManager.java
+++ b/core/java/android/hardware/camera2/CameraManager.java
@@ -720,6 +720,13 @@ public final class CameraManager {final int oomScoreOffset) throws CameraAccessException {CameraCharacteristics characteristics = getCameraCharacteristics(cameraId);CameraDevice device = null;
+        //add
+        if(SystemProperties.get("persist.sys.disablecamera").equals("true")){
+            Log.d(TAG, "camera2 sensor is close" + "LQX");
+
+            return null;
+        }
+        // endMap<String, CameraCharacteristics> physicalIdsToChars =getPhysicalIdToCharsMap(characteristics);synchronized (mLock) {