1# Mission Management Scenarios 2 3 4Before getting started with the development of mission management, be familiar with the following concepts related to mission management: 5 6 7- AbilityRecord: minimum unit for the system service to manage a UIAbility instance. It corresponds to a UIAbility component instance of an application. A maximum of 512 UIAbility instances can be managed on the system service side. 8 9- MissionRecord: minimum unit for mission management. One MissionRecord has only one AbilityRecord. In other words, a UIAbility component instance corresponds to a mission. 10 11- MissionList: a list of missions started from the home screen. It records the startup relationship between missions. In a MissionList, an above mission is started by the mission under it, and the mission at the bottom is started by the home screen. 12 13- MissionListManager: system mission management module that maintains all the MissionLists and is consistent with the list in **Recents**. 14 15 **Figure 1** Mission management 16  17 18 19Missions are managed by system applications (such as home screen), rather than third-party applications. Users interact with missions through **Recents**. After creating a mission, users can perform the following operations on **Recents**: 20 21 22- Delete a mission. 23 24- Lock or unlock a mission. (Locked missions are not cleared when users attempt to clear all missions in **Recents**.) 25 26- Clear all missions in **Recents**. 27 28- Switch a mission to the foreground. 29 30 31A UIAbility instance corresponds to an independent mission. Therefore, when an application calls [startAbility()](../reference/apis/js-apis-inner-application-uiAbilityContext.md#uiabilitycontextstartability) to start a UIAbility, a mission is created. 32 331. To call [missionManager](../reference/apis/js-apis-application-missionManager.md) to manage missions, the home screen application must request the **ohos.permission.MANAGE_MISSIONS** permission. For details about the configuration, see [Declaring Permissions in the Configuration File](../security/accesstoken-guidelines.md#declaring-permissions-in-the-configuration-file). 34 352. You can use **missionManager** to manage missions, for example, listening for mission changes, obtaining mission information or snapshots, and clearing, locking, or unlocking missions. 36 37 ```ts 38 import missionManager from '@ohos.app.ability.missionManager' 39 import { BusinessError } from '@ohos.base'; 40 41 let listener: missionManager.MissionListener = { 42 // Listen for mission creation. 43 onMissionCreated: (mission) => { 44 console.info("--------onMissionCreated-------") 45 }, 46 // Listen for mission destruction. 47 onMissionDestroyed: (mission) => { 48 console.info("--------onMissionDestroyed-------") 49 }, 50 // Listen for mission snapshot changes. 51 onMissionSnapshotChanged: (mission) => { 52 console.info("--------onMissionSnapshotChanged-------") 53 }, 54 // Listen for switching the mission to the foreground. 55 onMissionMovedToFront: (mission) => { 56 console.info("--------onMissionMovedToFront-------") 57 }, 58 // Listen for mission icon changes. 59 onMissionIconUpdated: (mission, icon) => { 60 console.info("--------onMissionIconUpdated-------") 61 }, 62 // Listen for mission name changes. 63 onMissionLabelUpdated: (mission) => { 64 console.info("--------onMissionLabelUpdated-------") 65 }, 66 // Listen for mission closure events. 67 onMissionClosed: (mission) => { 68 console.info("--------onMissionClosed-------") 69 } 70 }; 71 72 // 1. Register a mission change listener. 73 let listenerId = missionManager.on('mission', listener); 74 75 // 2. Obtain the latest 20 missions in the system. 76 missionManager.getMissionInfos("", 20, (error, missions) => { 77 console.info("getMissionInfos is called, error.code = " + error.code); 78 console.info("size = " + missions.length); 79 console.info("missions = " + JSON.stringify(missions)); 80 }); 81 82 // 3. Obtain the detailed information about a mission. 83 let missionId = 11; // The mission ID 11 is only an example. 84 let mission = missionManager.getMissionInfo("", missionId).catch((err: BusinessError) => { 85 console.info('${err.code}'); 86 }); 87 88 // 4. Obtain the mission snapshot. 89 missionManager.getMissionSnapShot("", missionId, (error, snapshot) => { 90 console.info("getMissionSnapShot is called, error.code = " + error.code); 91 console.info("bundleName = " + snapshot.ability.bundleName); 92 }) 93 94 // 5. Obtain the low-resolution mission snapshot. 95 missionManager.getLowResolutionMissionSnapShot("", missionId, (error, snapshot) => { 96 console.info("getLowResolutionMissionSnapShot is called, error.code = " + error.code); 97 console.info("bundleName = " + snapshot.ability.bundleName); 98 }) 99 100 // 6. Lock or unlock the mission. 101 missionManager.lockMission(missionId).then(() => { 102 console.info("lockMission is called "); 103 }); 104 105 missionManager.unlockMission(missionId).then(() => { 106 console.info("unlockMission is called "); 107 }); 108 109 // 7. Switch the mission to the foreground. 110 missionManager.moveMissionToFront(missionId).then(() => { 111 console.info("moveMissionToFront is called "); 112 }); 113 114 // 8. Clear a single mission. 115 missionManager.clearMission(missionId).then(() => { 116 console.info("clearMission is called "); 117 }); 118 119 // 9. Clear all missions. 120 missionManager.clearAllMissions().catch((err: BusinessError) => { 121 console.info('${err.code}'); 122 }); 123 124 // 10. Deregister the mission change listener. 125 missionManager.off('mission', listenerId, (error) => { 126 console.info("unregisterMissionListener"); 127 }) 128 ``` 129 130 131
