1# 设备输入(C/C++)
2
3在开发相机应用时，需要先参考开发准备[申请相关权限](camera-preparation.md)。
4
5相机应用通过调用和控制相机设备，完成预览、拍照和录像等基础操作。
6
7## 开发步骤
8
9详细的API说明请参考[Camera API参考](../../reference/apis-camera-kit/_o_h___camera.md)。
10
111. 导入NDK接口。选择系统提供的NDK接口能力，导入NDK接口的方法如下。
12
13   ```c++
14    // 导入NDK接口头文件
15    #include "hilog/log.h"
16    #include "ohcamera/camera.h"
17    #include "ohcamera/camera_input.h"
18    #include "ohcamera/capture_session.h"
19    #include "ohcamera/photo_output.h"
20    #include "ohcamera/preview_output.h"
21    #include "ohcamera/video_output.h"
22    #include "ohcamera/camera_manager.h"
23   ```
24
252. 在CMake脚本中链接相关动态库。
26
27   ```txt
28    target_link_libraries(entry PUBLIC libohcamera.so libhilog_ndk.z.so)
29   ```
30
313. 通过[OH_CameraManager_CreateCameraInput()](../../reference/apis-camera-kit/_o_h___camera.md#oh_cameramanager_createcamerainput)方法，获取cameraInput对象。
32
33   ```c++
34   Camera_Manager *cameraManager = nullptr;
35   Camera_Input* cameraInput = nullptr;
36   Camera_Device* cameras = nullptr;
37   Camera_OutputCapability* cameraOutputCapability = nullptr;
38   const Camera_Profile* previewProfile = nullptr;
39   const Camera_Profile* photoProfile = nullptr;
40   uint32_t size = 0;
41   uint32_t cameraDeviceIndex = 0;
42   // 创建CameraManager对象
43   Camera_ErrorCode ret = OH_Camera_GetCameraManager(&cameraManager);
44   if (cameraManager == nullptr || ret != CAMERA_OK) {
45      OH_LOG_ERROR(LOG_APP, "OH_Camera_GetCameraMananger failed.");
46   }
47   // 监听相机状态变化
48   ret = OH_CameraManager_RegisterCallback(cameraManager, GetCameraManagerListener());
49   if (ret != CAMERA_OK) {
50      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_RegisterCallback failed.");
51   }
52   // 获取相机列表
53    ret = OH_CameraManager_GetSupportedCameras(cameraManager, &cameras, &size);
54    if (cameras == nullptr || size < 0 || ret != CAMERA_OK) {
55      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameras failed.");
56    }
57   // 创建相机输入流
58   ret = OH_CameraManager_CreateCameraInput(cameraManager, &cameras[cameraDeviceIndex], &cameraInput);
59   if (cameraInput == nullptr || ret != CAMERA_OK) {
60      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCameraInput failed.");
61   }
62   ret == OH_CameraInput_RegisterCallback(cameraInput, GetCameraInputListener());
63   if (ret != CAMERA_OK) {
64      OH_LOG_ERROR(LOG_APP, "OH_CameraInput_RegisterCallback failed.");
65   }
66   // 打开相机
67   ret = OH_CameraInput_Open(cameraInput);
68   if (ret != CAMERA_OK) {
69      OH_LOG_ERROR(LOG_APP, "OH_CameraInput_open failed.");
70   }
71   ```
72   ```c++
73   // 监听cameraInput错误信息
74   void OnCameraInputError(const Camera_Input* cameraInput, Camera_ErrorCode errorCode)
75   {
76      OH_LOG_INFO(LOG_APP, "OnCameraInput errorCode: %{public}d", errorCode);
77   }
78
79   CameraInput_Callbacks* GetCameraInputListener(void)
80   {
81      static CameraInput_Callbacks cameraInputCallbacks = {
82         .onError = OnCameraInputError
83      };
84      return &cameraInputCallbacks;
85   }
86   ```
87
88   > **说明：**
89   >
90   > 在相机设备输入之前需要先完成相机管理，详细开发步骤请参考[相机管理](native-camera-device-management.md)
91
924. 通过[OH_CameraManager_GetSupportedSceneModes()](../../reference/apis-camera-kit/_o_h___camera.md#oh_cameramanager_getsupportedscenemodes)方法，获获取当前相机设备支持的模式列表，列表中存储了相机设备支持的所有模式[Camera_SceneMode](../../reference/apis-camera-kit/_o_h___camera.md#camera_scenemode)。
93
94   ```c++
95   Camera_SceneMode* sceneModes = nullptr;
96   uint32_t length = 0;
97   uint32_t sceneModeIndex = 0;
98   ret = OH_CameraManager_GetSupportedSceneModes(&cameras[cameraDeviceIndex], &sceneModes, &length);
99   if (sceneModes == nullptr || ret != CAMERA_OK) {
100      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedSceneModes failed.");
101   }
102   for (int index = 0; index < length; index++) {
103      OH_LOG_INFO(LOG_APP, "scene mode = %{public}s ", sceneModes[index]);    // 获取相机指定模式
104   }
105   ```
106
1075. 通过[OH_CameraManager_GetSupportedCameraOutputCapabilityWithSceneMode()](../../reference/apis-camera-kit/_o_h___camera.md#oh_cameramanager_getsupportedcameraoutputcapabilitywithscenemode)方法，获取当前设备支持的所有输出流，如预览流、拍照流等。输出流在CameraOutputCapability中的各个profile字段中。根据相机设备指定模式[Camera_SceneMode](../../reference/apis-camera-kit/_o_h___camera.md#camera_scenemode)的不同，需要添加不同类型的输出流。
108
109
110   ```c++
111   // 获取相机设备支持的输出流能力
112   Camera_OutputCapability* cameraOutputCapability = nullptr;
113   const Camera_Profile* previewProfile = nullptr;
114   const Camera_Profile* photoProfile = nullptr;
115   ret = OH_CameraManager_GetSupportedCameraOutputCapabilityWithSceneMode(cameraManager, &cameras[cameraDeviceIndex], sceneModes[sceneModeIndex]
116                                                                  &cameraOutputCapability);
117   if (cameraOutputCapability == nullptr || ret != CAMERA_OK) {
118      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameraOutputCapability failed.");
119   }
120   // 以NORMAL_PHOTO模式为例，需要添加预览流、拍照流
121   if (cameraOutputCapability->previewProfilesSize < 0) {
122      OH_LOG_ERROR(LOG_APP, "previewProfilesSize == null");
123   }
124   previewProfile = cameraOutputCapability->previewProfiles[0];
125
126   if (cameraOutputCapability->photoProfilesSize < 0) {
127      OH_LOG_ERROR(LOG_APP, "photoProfilesSize == null");
128   }
129   photoProfile = cameraOutputCapability->photoProfiles[0];
130   ```