未验证 提交 2fa1f90c 编写于 作者: L liyan 提交者: Gitee

同步master的3861创建helloworld章节

Signed-off-by: Nli-yan339 <liyan339@h-partners.com>
上级 b1ec20e0
# 新建应用程序<a name="ZH-CN_TOPIC_0000001216535387"></a>
下方将通过修改源码的方式展示如何编写简单程序,输出“Hello world.”。请在[获取源码](quickstart-lite-sourcecode-acquire.md)章节下载的源码目录中进行下述操作。
下方将通过修改源码的方式展示如何编写简单程序,输出“Hello world”。请在下载的源码目录中进行下述操作。
1. <a name="li5479332115116"></a>确定目录结构。
开发者编写业务时,务必先在./applications/sample/wifi-iot/app路径下新建一个目录(或一套目录结构),用于存放业务源码文件。
例如:在app下新增业务my\_first\_app,其中hello\_world.c为业务代码,BUILD.gn为编译脚本,具体规划目录结构如下:
例如:在app下新增业务my_first_app,其中hello_world.c为业务代码,BUILD.gn为编译脚本,具体规划目录结构如下:
```
.
......@@ -14,16 +14,16 @@
└── sample
└── wifi-iot
└── app
│── my_first_app
│ │── hello_world.c
│ └── BUILD.gn
└── BUILD.gn
```
└── my_first_app
│── hello_world.c
└── BUILD.gn
```
2. 编写业务代码。
新建./applications/sample/wifi-iot/app/my\_first\_app下的hello\_world.c文件,在hello\_world.c中新建业务入口函数HelloWorld,并实现业务逻辑。并在代码最下方,使用OpenHarmony启动恢复模块接口SYS\_RUN\(\)启动业务。(SYS\_RUN定义在ohos\_init.h文件中)
```
#include <stdio.h>
#include "ohos_init.h"
......@@ -57,21 +57,82 @@
- sources中指定静态库.a所依赖的.c文件及其路径,若路径中包含"//"则表示绝对路径(此处为代码根路径),若不包含"//"则表示相对路径。
- include\_dirs中指定source所需要依赖的.h文件路径。
4. 编写模块BUILD.gn文件,指定需参与构建的特性模块。
配置./applications/sample/wifi-iot/app/BUILD.gn文件,在features字段中增加索引,使目标模块参与编译。features字段指定业务模块的路径和目标,以my\_first\_app举例,features字段配置如下。
4. 添加新组件。
修改文件build/lite/components/applications.json,添加组件hello\_world\_app的配置,如下所示为applications.json文件片段,“##start##”和“##end##”之间为新增配置(“##start##”和“##end##”仅用来标识位置,添加完配置后删除这两行):
```
import("//build/lite/config/component/lite_component.gni")
lite_component("app") {
features = [
"my_first_app:myapp",
]
}
{
"components": [
{
"component": "camera_sample_communication",
"description": "Communication related samples.",
"optional": "true",
"dirs": [
"applications/sample/camera/communication"
],
"targets": [
"//applications/sample/camera/communication:sample"
],
"rom": "",
"ram": "",
"output": [],
"adapted_kernel": [ "liteos_a" ],
"features": [],
"deps": {
"components": [],
"third_party": []
}
},
##start##
{
"component": "hello_world_app",
"description": "hello world samples.",
"optional": "true",
"dirs": [
"applications/sample/wifi-iot/app/my_first_app"
],
"targets": [
"//applications/sample/wifi-iot/app/my_first_app:myapp"
],
"rom": "",
"ram": "",
"output": [],
"adapted_kernel": [ "liteos_m" ],
"features": [],
"deps": {
"components": [],
"third_party": []
}
},
##end##
{
"component": "camera_sample_app",
"description": "Camera related samples.",
"optional": "true",
"dirs": [
"applications/sample/camera/launcher",
"applications/sample/camera/cameraApp",
"applications/sample/camera/setting",
"applications/sample/camera/gallery",
"applications/sample/camera/media"
],
```
- my\_first\_app是相对路径,指向./applications/sample/wifi-iot/app/my\_first\_app/BUILD.gn。
- myapp是目标,指向./applications/sample/wifi-iot/app/my\_first\_app/BUILD.gn中的static\_library\("myapp"\)。
5. 修改单板配置文件。
修改文件vendor/hisilicon/hispark_pegasus/config.json,新增hello\_world\_app组件的条目,如下所示代码片段为applications子系统配置,“##start##”和“##end##”之间为新增条目(“##start##”和“##end##”仅用来标识位置,添加完配置后删除这两行):
```
{
"subsystem": "applications",
"components": [
##start##
{ "component": "hello_world_app", "features":[] },
##end##
{ "component": "wifi_iot_sample_app", "features":[] }
]
},
```
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