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 40 let listener = { 41 // Listen for mission creation. 42 onMissionCreated: function (mission) { 43 console.info("--------onMissionCreated-------") 44 }, 45 // Listen for mission destruction. 46 onMissionDestroyed: function (mission) { 47 console.info("--------onMissionDestroyed-------") 48 }, 49 // Listen for mission snapshot changes. 50 onMissionSnapshotChanged: function (mission) { 51 console.info("--------onMissionSnapshotChanged-------") 52 }, 53 // Listen for switching the mission to the foreground. 54 onMissionMovedToFront: function (mission) { 55 console.info("--------onMissionMovedToFront-------") 56 }, 57 // Listen for mission icon changes. 58 onMissionIconUpdated: function (mission, icon) { 59 console.info("--------onMissionIconUpdated-------") 60 }, 61 // Listen for mission name changes. 62 onMissionLabelUpdated: function (mission) { 63 console.info("--------onMissionLabelUpdated-------") 64 }, 65 // Listen for mission closure events. 66 onMissionClosed: function (mission) { 67 console.info("--------onMissionClosed-------") 68 } 69 }; 70 71 // 1. Register a mission change listener. 72 let listenerId = missionManager.on('mission', listener); 73 74 // 2. Obtain the latest 20 missions in the system. 75 missionManager.getMissionInfos("", 20, (error, missions) => { 76 console.info("getMissionInfos is called, error.code = " + error.code); 77 console.info("size = " + missions.length); 78 console.info("missions = " + JSON.stringify(missions)); 79 }); 80 81 // 3. Obtain the detailed information about a mission. 82 let missionId = 11; // The mission ID 11 is only an example. 83 let mission = missionManager.getMissionInfo("", missionId).catch(function (err) { 84 console.info(err); 85 }); 86 87 // 4. Obtain the mission snapshot. 88 missionManager.getMissionSnapShot("", missionId, (error, snapshot) => { 89 console.info("getMissionSnapShot is called, error.code = " + error.code); 90 console.info("bundleName = " + snapshot.ability.bundleName); 91 }) 92 93 // 5. Obtain the low-resolution mission snapshot. 94 missionManager.getLowResolutionMissionSnapShot("", missionId, (error, snapshot) => { 95 console.info("getLowResolutionMissionSnapShot is called, error.code = " + error.code); 96 console.info("bundleName = " + snapshot.ability.bundleName); 97 }) 98 99 // 6. Lock or unlock the mission. 100 missionManager.lockMission(missionId).then(() => { 101 console.info("lockMission is called "); 102 }); 103 104 missionManager.unlockMission(missionId).then(() => { 105 console.info("unlockMission is called "); 106 }); 107 108 // 7. Switch the mission to the foreground. 109 missionManager.moveMissionToFront(missionId).then(() => { 110 console.info("moveMissionToFront is called "); 111 }); 112 113 // 8. Clear a single mission. 114 missionManager.clearMission(missionId).then(() => { 115 console.info("clearMission is called "); 116 }); 117 118 // 9. Clear all missions. 119 missionManager.clearAllMissions().catch(function (err) { 120 console.info(err); 121 }); 122 123 // 10. Deregister the mission change listener. 124 missionManager.off('mission', listenerId, (error) => { 125 console.info("unregisterMissionListener"); 126 }) 127 ``` 128 129 130
