docs modify

Signed-off-by: Nzhangxin_T <zhangxin312@huawei.com>

zh-cn/application-dev/task-management/background-task-dev-guide.md

@@ -195,7 +195,7 @@ import featureAbility from '@ohos.ability.featureAbility';
 import wantAgent from '@ohos.wantAgent';
 import rpc from "@ohos.rpc";
 
-function startBackgroundRunning() {
+function startContinuousTask() {
     let wantAgentInfo = {
         // 点击通知后，将要执行的动作列表
         wants: [
@@ -223,7 +223,7 @@ function startBackgroundRunning() {
     });
 }
 
-function stopBackgroundRunning() {
+function stopContinuousTask() {
     backgroundTaskManager.stopBackgroundRunning(featureAbility.getContext()).then(() => {
         console.info("Operation stopBackgroundRunning succeeded");
     }).catch((err) => {
@@ -231,6 +231,13 @@ function stopBackgroundRunning() {
     });
 }
 
+async function processAsyncJobs() {
+    // 此处执行具体的长时任务。
+
+    // 长时任务执行完，调用取消接口，释放资源。
+    stopContinuousTask();
+}
+
 let mMyStub;
 
 class MyStub extends rpc.RemoteObject {
@@ -262,9 +269,9 @@ export default {
     onStart(want) {
         console.info('ServiceAbility onStart');
         mMyStub = new MyStub("ServiceAbility-test");
-        startBackgroundRunning();
-        // 此处执行后台具体的长时任务。
-        stopBackgroundRunning();
+        // 在执行后台长时任前，调用申请接口。
+        startContinuousTask();
+        processAsyncJobs();
     },
     onStop() {
         console.info('ServiceAbility onStop');