@ohos.app.ability.UIAbility (UIAbility)

UIAbility is an application component that has the UI. The UIAbility module provides lifecycle callback such as component creation, destruction, and foreground/background switching. It also provides the following capabilities related to component collaboration:

• Caller: an object returned by startAbilityByCall. The CallerAbility (caller) uses this object to communicate with the CalleeAbility (callee).
• Callee: an internal object of UIAbility. The CalleeAbility (callee) uses this object to communicate with the CallerAbility (caller).

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version. The APIs of this module can be used only in the stage model.

Modules to Import

import Ability from '@ohos.app.ability.UIAbility';

Attributes

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

UIAbility.onCreate

onCreate(want: Want, param: AbilityConstant.LaunchParam): void;

Called to initialize the service logic when an ability is created.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Example

class myAbility extends Ability {
    onCreate(want, param) {
        console.log('onCreate, want:' + want.abilityName);
    }
}

UIAbility.onWindowStageCreate

onWindowStageCreate(windowStage: window.WindowStage): void

Called when a WindowStage is created for this UIAbility.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Example

class myAbility extends Ability {
    onWindowStageCreate(windowStage) {
        console.log('onWindowStageCreate');
    }
}

UIAbility.onWindowStageDestroy

onWindowStageDestroy(): void

Called when the WindowStage is destroyed for this UIAbility.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Example

class myAbility extends Ability {
    onWindowStageDestroy() {
        console.log('onWindowStageDestroy');
    }
}

UIAbility.onWindowStageRestore

onWindowStageRestore(windowStage: window.WindowStage): void

Called when the WindowStage is restored during the migration of this UIAbility, which is a multi-instance ability.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Example

class myAbility extends Ability {
    onWindowStageRestore(windowStage) {
        console.log('onWindowStageRestore');
    }
}

UIAbility.onDestroy

onDestroy(): void | Promise<void>;

Called when this ability is destroyed to clear resources.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Example

class myAbility extends Ability {
    onDestroy() {
        console.log('onDestroy');
    }
}

UIAbility.onForeground

onForeground(): void;

Called when this ability is switched from the background to the foreground.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Example

class myAbility extends Ability {
    onForeground() {
        console.log('onForeground');
    }
}

UIAbility.onBackground

onBackground(): void;

Called when this ability is switched from the foreground to the background.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Example

class myAbility extends Ability {
    onBackground() {
        console.log('onBackground');
    }
}

UIAbility.onContinue

onContinue(wantParam: { [key: string]: Object }): AbilityConstant.OnContinueResult;

Called to save data during the ability migration preparation process.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Return value

Example

import AbilityConstant from '@ohos.app.ability.AbilityConstant';
class MyUIAbility extends Ability {
    onContinue(wantParams) {
        console.log('onContinue');
        wantParams['myData'] = 'my1234567';
        return AbilityConstant.OnContinueResult.AGREE;
    }
}

UIAbility.onNewWant

onNewWant(want: Want, launchParams: AbilityConstant.LaunchParam): void;

Called when a new Want is passed in and this UIAbility is started again.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Example

 class MyUIAbility extends Ability {
    onNewWant(want, launchParams) {
        console.log('onNewWant, want:' + want.abilityName);
        console.log('onNewWant, launchParams:' + JSON.stringify(launchParams));
     }
 }

UIAbility.onDump

onDump(params: Array<string>): Array<string>;

Dumps client information.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Example

class myAbility extends Ability {
    onDump(params) {
        console.log('dump, params:' + JSON.stringify(params));
        return ['params'];
    }
}

UIAbility.onSaveState

onSaveState(reason: AbilityConstant.StateType, wantParam : {[key: string]: Object}): AbilityConstant.OnSaveResult;

Called when the framework automatically saves the UIAbility state in the case of an application fault. This API is used together with appRecovery. If automatic state saving is enabled, onSaveState is called to save the state of this ability.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Return value

Example

import AbilityConstant from '@ohos.app.ability.AbilityConstant';

class MyUIAbility extends Ability {
  onSaveState(reason, wantParam) {
      console.log('onSaveState');
      wantParam['myData'] = 'my1234567';
      return AbilityConstant.OnSaveResult.RECOVERY_AGREE;
  }
}

Caller

Implements sending of parcelable data to the target ability when the CallerAbility invokes the target ability (CalleeAbility).

Caller.call

call(method: string, data: rpc.Parcelable): Promise<void>;

Sends parcelable data to the target ability.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

class MyMessageAble{ // Custom parcelable data structure.
  name:''
  str:''
  num: 1
  constructor(name, str) {
    this.name = name;
    this.str = str;
  }
  marshalling(messageSequence) {
    messageSequence.writeInt(this.num);
    messageSequence.writeString(this.str);
    console.log('MyMessageAble marshalling num[' + this.num + '] str[' + this.str + ']');
    return true;
  }
  unmarshalling(messageSequence) {
    this.num = messageSequence.readInt();
    this.str = messageSequence.readString();
    console.log('MyMessageAble unmarshalling num[' + this.num + '] str[' + this.str + ']');
    return true;
  }
};
let method = 'call_Function'; // Notification message string negotiated by the two abilities.
let caller;
export default class MainAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainAbility',
      deviceId: ''
    }).then((obj) => {
      caller = obj;
      let msg = new MyMessageAble('msg', 'world'); // See the definition of Parcelable.
      caller.call(method, msg)
        .then(() => {
          console.log('Caller call() called');
        })
        .catch((callErr) => {
          console.log('Caller.call catch error, error.code: ' + JSON.stringify(callErr.code) +
            ' error.message: ' + JSON.stringify(callErr.message));
        });
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.callWithResult

callWithResult(method: string, data: rpc.Parcelable): Promise<rpc.MessageSequence>;

Sends parcelable data to the target ability and obtains the parcelable data returned by the target ability.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

class MyMessageAble{
  name:''
  str:''
  num: 1
  constructor(name, str) {
    this.name = name;
    this.str = str;
  }
  marshalling(messageSequence) {
    messageSequence.writeInt(this.num);
    messageSequence.writeString(this.str);
    console.log('MyMessageAble marshalling num[' + this.num + '] str[' + this.str + ']');
    return true;
  }
  unmarshalling(messageSequence) {
    this.num = messageSequence.readInt();
    this.str = messageSequence.readString();
    console.log('MyMessageAble unmarshalling num[' + this.num + '] str[' + this.str + ']');
    return true;
  }
};
let method = 'call_Function';
let caller;
export default class MainAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainAbility',
      deviceId: ''
    }).then((obj) => {
      caller = obj;
      let msg = new MyMessageAble(1, 'world');
      caller.callWithResult(method, msg)
        .then((data) => {
          console.log('Caller callWithResult() called');
          let retmsg = new MyMessageAble(0, '');
          data.readParcelable(retmsg);
        })
        .catch((callErr) => {
          console.log('Caller.callWithResult catch error, error.code: ' + JSON.stringify(callErr.code) +
            ' error.message: ' + JSON.stringify(callErr.message));
        });
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.release

release(): void;

Releases the caller interface of the target ability.

System capability: SystemCapability.UIAbility.UIAbilityRuntime.UIAbilityCore

Error codes

For details about the error codes, see Ability Error Codes.

Example

let caller;
export default class MainAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainAbility',
      deviceId: ''
    }).then((obj) => {
      caller = obj;
      try {
        caller.release();
      } catch (releaseErr) {
        console.log('Caller.release catch error, error.code: ' + JSON.stringify(releaseErr.code) +
          ' error.message: ' + JSON.stringify(releaseErr.message));
      }
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.onRelease

onRelease(callback: OnReleaseCallback): void;

Registers a callback that is invoked when the stub on the target ability is disconnected.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Error codes

For details about the error codes, see Ability Error Codes.

Parameters

Example

let caller;
export default class MainAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainAbility',
      deviceId: ''
    }).then((obj) => {
        caller = obj;
        try {
          caller.onRelease((str) => {
              console.log(' Caller OnRelease CallBack is called ' + str);
          });
        } catch (error) {
          console.log('Caller.onRelease catch error, error.code: ' + JSON.stringify(error.code) +
            ' error.message: ' + JSON.stringify(error.message));
        }
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.on

on(type: 'release', callback: OnReleaseCallback): void;

Registers a callback that is invoked when the stub on the target ability is disconnected.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let caller;
export default class MainAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainAbility',
      deviceId: ''
    }).then((obj) => {
        caller = obj;
        try {
          caller.on('release', (str) => {
              console.log(' Caller OnRelease CallBack is called ' + str);
          });
        } catch (error) {
          console.log('Caller.on catch error, error.code: ' + JSON.stringify(error.code) +
            ' error.message: ' + JSON.stringify(error.message));
        }
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.off

off(type: 'release', callback: OnReleaseCallback): void;

Deregisters a callback that is invoked when the stub on the target ability is disconnected. This capability is reserved.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let caller;
export default class MainUIAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainUIAbility',
      deviceId: ''
    }).then((obj) => {
        caller = obj;
        try {
          let onReleaseCallBack = (str) => {
              console.log(' Caller OnRelease CallBack is called ' + str);
          };
          caller.on('release', onReleaseCallBack);
          caller.off('release', onReleaseCallBack);
        } catch (error) {
          console.log('Caller.on or Caller.off catch error, error.code: ' + JSON.stringify(error.code) +
            ' error.message: ' + JSON.stringify(error.message));
        }
    }).catch((err) => {
      console.log('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Caller.off

off(type: 'release'): void;

Deregisters a callback that is invoked when the stub on the target ability is disconnected. This capability is reserved.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let caller;
export default class MainUIAbility extends Ability {
  onWindowStageCreate(windowStage) {
    this.context.startAbilityByCall({
      bundleName: 'com.example.myservice',
      abilityName: 'MainUIAbility',
      deviceId: ''
    }).then((obj) => {
        caller = obj;
        try {
          let onReleaseCallBack = (str) => {
              console.log(' Caller OnRelease CallBack is called ' + str);
          };
          caller.on('release', onReleaseCallBack);
          caller.off('release');
        } catch (error) {  
          console.error('Caller.on or Caller.off catch error, error.code: ' + JSON.stringify(error.code) +
            ' error.message: ' + JSON.stringify(error.message));
        }
    }).catch((err) => {
      console.error('Caller GetCaller error, error.code: ' + JSON.stringify(err.code) +
        ' error.message: ' + JSON.stringify(err.message));
    });
  }
}

Callee

Implements callbacks for caller notification registration and deregistration.

Callee.on

on(method: string, callback: CalleeCallback): void;

Registers a caller notification callback, which is invoked when the target ability registers a function.

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

class MyMessageAble{
    name:''
    str:''
    num: 1
    constructor(name, str) {
      this.name = name;
      this.str = str;
    }
    marshalling(messageSequence) {
        messageSequence.writeInt(this.num);
        messageSequence.writeString(this.str);
        console.log('MyMessageAble marshalling num[' + this.num + '] str[' + this.str + ']');
        return true;
    }
    unmarshalling(messageSequence) {
        this.num = messageSequence.readInt();
        this.str = messageSequence.readString();
        console.log('MyMessageAble unmarshalling num[' + this.num + '] str[' + this.str + ']');
        return true;
    }
};
let method = 'call_Function';
function funcCallBack(pdata) {
    console.log('Callee funcCallBack is called ' + pdata);
    let msg = new MyMessageAble('test', '');
    pdata.readParcelable(msg);
    return new MyMessageAble('test1', 'Callee test');
}
export default class MainAbility extends Ability {
  onCreate(want, launchParam) {
    console.log('Callee onCreate is called');
    try {
      this.callee.on(method, funcCallBack);
    } catch (error) {
      console.log('Callee.on catch error, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    }
  }
}

Callee.off

off(method: string): void;

Deregisters a caller notification callback, which is invoked when the target ability registers a function.

System capability: SystemCapability.UIAbility.UIAbilityRuntime.UIAbilityCore

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let method = 'call_Function';
export default class MainAbility extends Ability {
  onCreate(want, launchParam) {
    console.log('Callee onCreate is called');
    try {
      this.callee.off(method);
    } catch (error) {
      console.log('Callee.off catch error, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    }
  }
}

OnReleaseCallback

(msg: string): void;

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore

CalleeCallback

(indata: rpc.MessageSequence): rpc.Parcelable;

System capability: SystemCapability.Ability.AbilityRuntime.AbilityCore