應(yīng)用組件間的信息傳遞

導(dǎo)入模塊

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

屬性

系統(tǒng)能力：以下各項對應(yīng)的系統(tǒng)能力均為SystemCapability.Ability.AbilityBase

示例：

• 基礎(chǔ)用法

    let want = {
        'deviceId': '', // deviceId為空表示本設(shè)備
        'bundleName': 'com.extreme.test',
        'abilityName': 'MainAbility',
        'moduleName': 'entry' // moduleName非必選
    };
    this.context.startAbility(want, (error) => {
        // 顯式拉起Ability，通過bundleName、abilityName和moduleName可以唯一確定一個Ability
        console.log('error.code = ' + error.code);
    })

• 通過自定字段傳遞數(shù)據(jù)，以下為當(dāng)前支持類型。

  • 字符串（String）

    let want = {
        bundleName: 'com.example.demo',
        abilityName: 'com.example.demo.MainAbility',
        parameters: {
            keyForString: 'str',
        },
    };

  • 數(shù)字（Number）

    let want = {
        bundleName: 'com.example.demo',
        abilityName: 'com.example.demo.MainAbility',
        parameters: {
            keyForInt: 100,
            keyForDouble: 99.99,
        },
    };

  • 布爾（Boolean）

    let want = {
        bundleName: 'com.example.demo',
        abilityName: 'com.example.demo.MainAbility',
        parameters: {
            keyForBool: true,
        },
    };

  • 對象（Object）

    let want = {
        bundleName: 'com.example.demo',
        abilityName: 'com.example.demo.MainAbility',
        parameters: {
            keyForObject: {
                keyForObjectString: 'str',
                keyForObjectInt: -200,
                keyForObjectDouble: 35.5,
                keyForObjectBool: false,
            },
        },
    };

  • 數(shù)組（Array）

    let want = {
        bundleName: 'com.example.demo',
        abilityName: 'com.example.demo.MainAbility',
        parameters: {
            keyForArrayString: ['str1', 'str2', 'str3'],
            keyForArrayInt: [100, 200, 300, 400],
            keyForArrayDouble: [0.1, 0.2],
            keyForArrayObject: [{obj1: 'aaa'}, {obj2: 100}],
        },
    };

  • 文件描述符（FD）

        import fileio from '@ohos.fileio';
        let fd;
        try {
            fd = fileio.openSync('/data/storage/el2/base/haps/pic.png');
        } catch(e) {
            console.log('openSync fail:' + JSON.stringify(e));
        }
        let want = {
            'deviceId': '', // deviceId為空表示本設(shè)備
            'bundleName': 'com.extreme.test',
            'abilityName': 'MainAbility',
            'moduleName': 'entry', // moduleName非必選
            'parameters': {
                'keyFd':{'type':'FD', 'value':fd} // {'type':'FD', 'value':fd}是固定用法，用于表示該數(shù)據(jù)是FD
            }
        };
        this.context.startAbility(want, (error) => {
            // 顯式拉起Ability，通過bundleName、abilityName和moduleName可以唯一確定一個Ability
            console.log('error.code = ' + error.code);
        });

  • parameter參數(shù)用法：以ability.params.backToOtherMissionStack為例，ServiceExtension在拉起UIAbility的時候，可以支持跨任務(wù)鏈返回。

        // (1) UIAbility1啟動一個ServiceExtension
        let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext
        let want = {
          bundleName: 'com.example.myapplication1',
          abilityName: 'ServiceExtensionAbility',
        };
    
        context.startAbility(want, (err) => {
          console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`);
        });
    
        // (2) 該ServiceExtension去啟動另一個UIAbility2，并在啟動的時候攜帶參數(shù)ability.params.backToOtherMissionStack為true
        let context = ...; // ServiceExtensionContext
        let want = {
          bundleName: 'com.example.myapplication2',
          abilityName: 'MainAbility',
          parameters: {
            "ability.params.backToOtherMissionStack": true,
          },
        };
    
        context.startAbility(want, (err) => {
          console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`);
        });
    
    

    在上述例子中：

    • 如果ServiceExtension啟動UIAbility2時，不攜帶ability.params.backToOtherMissionStack參數(shù)，或者攜帶的ability.params.backToOtherMissionStack參數(shù)為false，則UIAbility1和UIAbility2不在同一個任務(wù)棧里面，在UIAbility2的界面點back鍵，不會回到UIAbility1的界面。
    • 如果攜帶的ability.params.backToOtherMissionStack參數(shù)為true，則表示支持跨任務(wù)鏈返回，此時在UIAbility2的界面點back鍵，會回到UIAbility1的界面。