HarmonyOS 实战—服务卡片初体验
发布于: 1 小时前
最近看到很多博客网站上出现了 HarmonyOS 的征文活动，看到那些精美的奖品让我也安耐不住开了，当然奖品的诱惑当然是抵挡不住我对技术的狂热追求，对于开发者而言技术没有顶峰没有终点。那么今天给大家做一个卡片服务开发的经验分享，如果有什么地方说的不对的请各位开发者进行指正，如果有什么问题也可以发私信或者直接在帖子中留言，我也会及时回复大家。
一、什么是卡片服务
服务卡片（以下简称“卡片”）是FA的一种界面展示形式，将FA的重要信息或操作直接放置到卡片中，用户通过直接操作卡片就可以达到应用的使用体验，这样做大大减少了应用的使用层级性。
卡片常用于嵌入到其他应用中作为其界面的一部分显示（也可以使用原子化服务将应用保存到服务中心中，这种方式不需要安装应用），并支持拉起页面，发送消息等基础的交互功能。
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原子化服务在下个帖子中介绍。
示例如下图所示。
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为了开发者能够便于理解，官方将卡片服务分为三方面：
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卡片使用方
显示卡片内容的宿主应用，控制卡片在宿主中展示的位置。
卡片管理服务
用于管理系统中所添加卡片的常驻代理服务，包括卡片对象的管理与使用，以及卡片周期性刷新等。
卡片提供方
提供卡片显示内容的 HarmonyOS 应用或原子化服务，控制卡片的显示内容、控件布局以及控件点击事件。
卡片使用方和提供方不要求常驻运行，在需要添加/删除/请求更新卡片时，卡片管理服务会拉起卡片提供方获取卡片信息。
二、卡片服务的运作机制
文字描述滞后，先上图。（图片由官网提供，此处借用一下）
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从图中可以清楚的看到卡片服务的整体通信层都是由"RPC"负责，通过通信适配层构成了数据发送接收的通道。
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卡片管理服务
周期性刷新：在卡片添加后，根据卡片的刷新策略启动定时任务周期性触发卡片的刷新。
卡片缓存管理：在卡片添加到卡片管理服务后，对卡片的视图信息进行缓存，以便下次获取卡片时可以直接返回缓存数据，降低时延。
卡片生命周期管理：对于卡片切换到后台或者被遮挡时，暂停卡片的刷新；以及卡片的升级/卸载场景下对卡片数据的更新和清理。
卡片使用方对象管理：对卡片使用方的 RPC 对象进行管理，用于使用方请求进行校验以及对卡片更新后的回调处理。
卡片提供方
创建卡片实例并实现 onCreateForm、onUpdateForm 和 onDeleteForm 处理创建卡片、更新卡片以及删除卡片等请求，提供相应的卡片服务。
三、卡片服务的实现（java）
第一步、下载、安装、配置 DevEco Studio
第二步、运行 DevEco Studio 创建新项目
因为要使用 java 语言编写，所以此处要选择支持 Java 语言的空页面。
选择成功进入新建项目配置界面。
点击 Finish 进入项目。
第三步、添加卡片模板
创建模板：右击“Entry”→“New”→“Server Widget”
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第四步、查看卡片服务配置
项目目录
由图可见：添加卡片模板后在原来项目中增加一个widget文件夹，并在文件夹中出现了三个文件FormControllerManager.java、FormController.java、CardWidgetImpl.java。三个文件对应了卡片服务的运行机制，通过关系的对应可以清楚的了解到代码运行原理。
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FormControllerManager.java（卡片控制器管理【卡片服务管理】）
public class FormControllerManager { private static final HiLogLabel TAG = new HiLogLabel(HiLog.DEBUG, 0x0, FormControllerManager.class.getName()); private static final String PACKAGE\_PATH = "com.example.carddemo.widget"; private static final String SHARED\_SP\_NAME = "form\_info\_sp.xml"; private static final String FORM\_NAME = "formName"; private static final String DIMENSION = "dimension"; private static FormControllerManager managerInstance = null; private final HashMap<Long, FormController> controllerHashMap = new HashMap<>(); private final Context context; private final Preferences preferences; /** * 初始化构造器 * * @param context instance of Context. */ private FormControllerManager(Context context) { this.context = context; DatabaseHelper databaseHelper = new DatabaseHelper(this.context.getApplicationContext()); preferences = databaseHelper.getPreferences(SHARED\_SP\_NAME); } /** * FormControllerManager 实例化 * * @param context instance of Context. * @return FormControllerManager instance. */ public static FormControllerManager getInstance(Context context) { if (managerInstance == null) { synchronized (FormControllerManager.class) { if (managerInstance == null) { managerInstance = new FormControllerManager(context); } } } return managerInstance; } /** * 通过构造器将传入的卡片信息进行封装，返回卡片服务 * * @param formId form id. * @param formName form name. * @param dimension form dimension * @return FormController form controller */ public FormController createFormController(long formId, String formName, int dimension) { synchronized (controllerHashMap) { if (formId < 0 || formName.isEmpty()) { return null; } HiLog.info(TAG, "saveFormId() formId: " + formId + ", formName: " + formName + ", preferences: " + preferences); if (preferences != null) { ZSONObject formObj = new ZSONObject(); formObj.put(FORM_NAME, formName); formObj.put(DIMENSION, dimension); preferences.putString(Long.toString(formId), ZSONObject.toZSONString(formObj)); preferences.flushSync(); } // Create controller instance. FormController controller = newInstance(formName, dimension, context); // Cache the controller. if (controller != null) { if (!controllerHashMap.containsKey(formId)) { controllerHashMap.put(formId, controller); } } return controller; } } /** * 获取卡片控制器实例 * * @param formId form id. * @return the instance of form controller. */ public FormController getController(long formId) { synchronized (controllerHashMap) { if (controllerHashMap.containsKey(formId)) { return controllerHashMap.get(formId); } Map<String, ?> forms = preferences.getAll(); String formIdString = Long.toString(formId); if (forms.containsKey(formIdString)) { ZSONObject formObj = ZSONObject.stringToZSON((String) forms.get(formIdString)); String formName = formObj.getString(FORM_NAME); int dimension = formObj.getIntValue(DIMENSION); FormController controller = newInstance(formName, dimension, context); controllerHashMap.put(formId, controller); } return controllerHashMap.get(formId); } } private FormController newInstance(String formName, int dimension, Context context) { FormController ctrInstance = null; if (formName == null || formName.isEmpty()) { HiLog.error(TAG, "newInstance() get empty form name"); return ctrInstance; } try { String className = PACKAGE_PATH + "." + formName.toLowerCase(Locale.ROOT) + "." + getClassNameByFormName(formName); Class<?> clazz = Class.forName(className); if (clazz != null) { Object controllerInstance = clazz.getConstructor(Context.class, String.class, Integer.class) .newInstance(context, formName, dimension); if (controllerInstance instanceof FormController) { ctrInstance = (FormController) controllerInstance; } } } catch (NoSuchMethodException | InstantiationException | IllegalArgumentException | InvocationTargetException | IllegalAccessException | ClassNotFoundException | SecurityException exception) { HiLog.error(TAG, "newInstance() get exception: " + exception.getMessage()); } return ctrInstance; } /** * 从数组中获取所有卡片id * * @return form id list */ public List<Long> getAllFormIdFromSharePreference() { List<Long> result = new ArrayList<>(); Map<String, ?> forms = preferences.getAll(); for (String formId : forms.keySet()) { result.add(Long.parseLong(formId)); } return result; } /** * 删除卡片服务 * * @param formId form id */ public void deleteFormController(long formId) { synchronized (controllerHashMap) { preferences.delete(Long.toString(formId)); preferences.flushSync(); controllerHashMap.remove(formId); } } private String getClassNameByFormName(String formName) { String\[\] strings = formName.split("_"); StringBuilder result = new StringBuilder(); for (String string : strings) { result.append(string); } char\[\] charResult = result.toString().toCharArray(); charResult\[0\] = (charResult\[0\] >= 'a' && charResult\[0\] <= 'z') ? (char) (charResult\[0\] - 32) : charResult\[0\]; return String.copyValueOf(charResult) + "Impl"; }}
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FormController.java（卡片控制器【卡片提供方】）
public abstract class FormController { protected final Context context; protected final String formName; protected final int dimension; public FormController(Context context, String formName, Integer dimension) { this.context = context; this.formName = formName; this.dimension = dimension; } /** * 创建卡片信息提供者 */ public abstract ProviderFormInfo bindFormData(); /** * 更新卡片信息 */ public abstract void updateFormData(long formId, Object... vars); /** * 在接收服务小部件消息事件时调用 */ public abstract void onTriggerFormEvent(long formId, String message); /** * 获取路由的目标界面 */ public abstract Class<? extends AbilitySlice> getRoutePageSlice(Intent intent);}
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CardWidgetImpl.java（卡片应用【卡片使用方】）
public class CardWidgetImpl extends FormController { public static final int DIMENSION\_1X2 = 1; public static final int DIMENSION\_2X4 = 3; private static final HiLogLabel TAG = new HiLogLabel(HiLog.DEBUG, 0x0, CardWidgetImpl.class.getName()); private static final int DEFAULT\_DIMENSION\_2X2 = 2; private static final Map<Integer, Integer> RESOURCE\_ID\_MAP = new HashMap<>(); static { RESOURCE\_ID\_MAP.put(DIMENSION\_1X2, ResourceTable.Layout\_form\_grid\_pattern\_cardwidget\_1_2); RESOURCE\_ID\_MAP.put(DEFAULT\_DIMENSION\_2X2, ResourceTable.Layout\_form\_grid\_pattern\_cardwidget\_2\_2); RESOURCE\_ID\_MAP.put(DIMENSION\_2X4, ResourceTable.Layout\_form\_grid\_pattern\_cardwidget\_2_4); } public CardWidgetImpl(Context context, String formName, Integer dimension) { super(context, formName, dimension); } //创建好卡片服务后，在界面展示卡片 @Override public ProviderFormInfo bindFormData() { HiLog.info(TAG, "bind form data when create form"); return new ProviderFormInfo(RESOURCE\_ID\_MAP.get(dimension), context); } //更新卡片信息 @Override public void updateFormData(long formId, Object... vars) { HiLog.info(TAG, "update form data timing, default 30 minutes"); } //卡片中内容手势触发方法 @Override public void onTriggerFormEvent(long formId, String message) { HiLog.info(TAG, "handle card click event."); } @Override public Class<? extends AbilitySlice> getRoutePageSlice(Intent intent) { HiLog.info(TAG, "get the default page to route when you click card."); return null; }}
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MainAbility 的变化，新增了一些方法。
public class MainAbility extends Ability { public static final int DEFAULT\_DIMENSION\_2X2 = 2; public static final int DIMENSION\_1X2 = 1; public static final int DIMENSION\_2X4 = 3; public static final int DIMENSION\_4X4 = 4; private static final int INVALID\_FORM_ID = -1; private static final HiLogLabel TAG = new HiLogLabel(HiLog.DEBUG, 0x0, MainAbility.class.getName()); private String topWidgetSlice; @Override public void onStart(Intent intent) { super.onStart(intent); super.setMainRoute(MainAbilitySlice.class.getName()); if (intentFromWidget(intent)) { topWidgetSlice = getRoutePageSlice(intent); if (topWidgetSlice != null) { setMainRoute(topWidgetSlice); } } stopAbility(intent); } //创建卡片信息并返回卡片内容 @Override protected ProviderFormInfo onCreateForm(Intent intent) { HiLog.info(TAG, "onCreateForm"); long formId = intent.getLongParam(AbilitySlice.PARAM\_FORM\_IDENTITY\_KEY, INVALID\_FORM_ID); String formName = intent.getStringParam(AbilitySlice.PARAM\_FORM\_NAME\_KEY); int dimension = intent.getIntParam(AbilitySlice.PARAM\_FORM\_DIMENSION\_KEY, DEFAULT\_DIMENSION\_2X2); HiLog.info(TAG, "onCreateForm: formId=" + formId + ",formName=" + formName); FormControllerManager formControllerManager = FormControllerManager.getInstance(this); FormController formController = formControllerManager.getController(formId); //通过调用布局Id将卡片布局与卡片信息进行绑定 formController = (formController == null) ? formControllerManager.createFormController(formId, formName, dimension) : formController; if (formController == null) { HiLog.error(TAG, "Get null controller. formId: " + formId + ", formName: " + formName); return null; } return formController.bindFormData(); } //更新卡片信息 @Override protected void onUpdateForm(long formId) { HiLog.info(TAG, "onUpdateForm"); super.onUpdateForm(formId); FormControllerManager formControllerManager = FormControllerManager.getInstance(this); FormController formController = formControllerManager.getController(formId); formController.updateFormData(formId); } //删除卡片 @Override protected void onDeleteForm(long formId) { HiLog.info(TAG, "onDeleteForm: formId=" + formId); super.onDeleteForm(formId); FormControllerManager formControllerManager = FormControllerManager.getInstance(this); formControllerManager.deleteFormController(formId); } //卡片手势触发 @Override protected void onTriggerFormEvent(long formId, String message) { HiLog.info(TAG, "onTriggerFormEvent: " + message); super.onTriggerFormEvent(formId, message); FormControllerManager formControllerManager = FormControllerManager.getInstance(this); FormController formController = formControllerManager.getController(formId); formController.onTriggerFormEvent(formId, message); } @Override public void onNewIntent(Intent intent) { if (intentFromWidget(intent)) { // Only response to it when starting from a service widget. String newWidgetSlice = getRoutePageSlice(intent); if (topWidgetSlice == null || !topWidgetSlice.equals(newWidgetSlice)) { topWidgetSlice = newWidgetSlice; restart(); } } } private boolean intentFromWidget(Intent intent) { long formId = intent.getLongParam(AbilitySlice.PARAM\_FORM\_IDENTITY\_KEY, INVALID\_FORM\_ID); return formId != INVALID\_FORM_ID; } //跳转至对应的卡片界面 private String getRoutePageSlice(Intent intent) { long formId = intent.getLongParam(AbilitySlice.PARAM\_FORM\_IDENTITY\_KEY, INVALID\_FORM\_ID); if (formId == INVALID\_FORM_ID) { return null; } FormControllerManager formControllerManager = FormControllerManager.getInstance(this); FormController formController = formControllerManager.getController(formId); if (formController == null) { return null; } Class<? extends AbilitySlice> clazz = formController.getRoutePageSlice(intent); if (clazz == null) { return null; } return clazz.getName(); }}
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配置文件
第五步、编写卡片界面
分别修改 form_grid_pattern_cardwidget_1_2、form_grid_pattern_cardwidget_2_2.xml 和 form_grid_pattern_cardwidget_2_4.xml 文件。
form_grid_pattern_cardwidget_1_2.xml
<?xml version="1.0" encoding="utf-8"?><DependentLayout xmlns:ohos="http://schemas.huawei.com/res/ohos" ohos:height="match_parent" ohos:width="match_parent" ohos:remote="true"> <Image ohos:height="match_parent" ohos:width="match_parent" ohos:background_element="#1281f0" ohos:scale\_mode="clip\_center"/> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:alignment="center" ohos:orientation="horizontal"> <Text ohos:id="$+id:tv_name" ohos:height="match_content" ohos:width="match_content" ohos:text="$string:cardwidget_title" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="1200"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="3350" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="1200"/> </DirectionalLayout></DependentLayout>
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form_grid_pattern_cardwidget_2_2.xml
<?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos" ohos:height="match_parent" ohos:width="match_parent" ohos:background_element="#FFFFFFFF" ohos:remote="true" ohos:orientation="vertical"> <DirectionalLayout ohos:id="$+id:tv_top" ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="horizontal"> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="vertical" ohos:alignment="center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="消耗热量" ohos:top_margin="5vp" ohos:text_size="10fp" ohos:text_weight="500"> </Text> <Text ohos:height="60vp" ohos:width="60vp" ohos:text="2.1 Kcal" ohos:text_alignment="center" ohos:text_color="#1281f0" ohos:background\_element="$media:aa\_1" ohos:text_size="10fp" ohos:text_weight="500"/> </DirectionalLayout> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="vertical" ohos:alignment="center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="实时心率" ohos:top_margin="5vp" ohos:text_size="10fp" ohos:text_weight="500"> </Text> <Text ohos:height="60vp" ohos:width="60vp" ohos:text="99/min" ohos:text_alignment="center" ohos:text_color="#1281f0" ohos:background\_element="$media:aa\_1" ohos:text_size="10fp" ohos:text_weight="500"/> </DirectionalLayout> </DirectionalLayout> <DirectionalLayout ohos:id="$+id:tv_blow" ohos:height="60vp" ohos:width="match_parent" ohos:align\_parent\_bottom="true" ohos:background_element="#1281f0" ohos:alignment="center" ohos:orientation="vertical"> <DirectionalLayout ohos:height="match_content" ohos:width="match_parent" ohos:alignment="center" ohos:orientation="horizontal"> <Text ohos:id="$+id:tv_name" ohos:height="match_content" ohos:width="match_content" ohos:text="$string:cardwidget_title" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="600"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="3350" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="1000"/> </DirectionalLayout> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="$string:cardwidget_introduction" ohos:text_color="#ffffff" ohos:text_size="14fp" ohos:text_weight="800" ohos:top_margin="7vp"/> </DirectionalLayout></DirectionalLayout>
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form_grid_pattern_cardwidget_2_4.xml
<?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos" ohos:height="match_parent" ohos:width="match_parent" ohos:background_element="#FFFFFFFF" ohos:orientation="horizontal" ohos:remote="true"> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="vertical"> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="horizontal"> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="vertical" ohos:alignment="center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="消耗热量" ohos:top_margin="5vp" ohos:text_size="10fp" ohos:text_weight="500"> </Text> <Text ohos:height="60vp" ohos:width="60vp" ohos:text="2.1 Kcal" ohos:text_alignment="center" ohos:text_color="#1281f0" ohos:background\_element="$media:aa\_1" ohos:text_size="10fp" ohos:text_weight="500"/> </DirectionalLayout> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1" ohos:orientation="vertical" ohos:alignment="center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="实时心率" ohos:top_margin="5vp" ohos:text_size="10fp" ohos:text_weight="500"> </Text> <Text ohos:height="60vp" ohos:width="60vp" ohos:text="99/min" ohos:text_alignment="center" ohos:text_color="#1281f0" ohos:background\_element="$media:aa\_1" ohos:text_size="10fp" ohos:text_weight="500"/> </DirectionalLayout> </DirectionalLayout> <DirectionalLayout ohos:height="60vp" ohos:width="match_parent" ohos:align\_parent\_bottom="true" ohos:background_element="#1281f0" ohos:alignment="center" ohos:orientation="vertical"> <DirectionalLayout ohos:height="match_content" ohos:width="match_parent" ohos:alignment="center" ohos:orientation="horizontal"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="$string:cardwidget_title" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="600"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="3350" ohos:text_color="#E5FFFFFF" ohos:text_size="16fp" ohos:text_weight="1000"/> </DirectionalLayout> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="$string:cardwidget_introduction" ohos:text_color="#ffffff" ohos:text_size="14fp" ohos:text_weight="800" ohos:top_margin="7vp"/> </DirectionalLayout> </DirectionalLayout> <DirectionalLayout ohos:height="match_parent" ohos:width="match_parent" ohos:weight="1"> </DirectionalLayout></DirectionalLayout>
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第六步、运行程序、查看效果
点击图标上划，出现卡片。
点击右上角图钉按钮，将卡片放在屏幕中。
长按应用，出现服务卡片。
点击服务卡片选择界面，上下滑动可选择卡片内容。
点击添加到桌面，则将卡片添加到桌面中。
至此，卡片服务应用就以全部开发完成，后续会对卡片内部进行相关编写。使其进行动态的刷新及动态的获取数据。
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版权声明: 本文为 InfoQ 作者【爱吃土豆丝的打工人】的原创文章。
原文链接:【http://xie.infoq.cn/article/7320dd1165d9a0c2cff550ae4】。文章转载请联系作者。
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精通移动开发、Android开发； 熟练应用java/JavaScript进行HarmonyOS开发； 熟练使用HTML/CSS语言进行网页开发。
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