首选项

用户首选项

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1key 1MB, value 16MB
2存储系统变量，如主题、字体、用户个性化设置
3系统一次性读取全部存储值，默认操作内存，数据都在内存中
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5异步存储，需要调用flush存到硬盘

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 1import { preferences } from '@kit.ArkData'
 2import { BusinessError } from '@kit.BasicServicesKit'
 3
 4export class PreferencesUtil {
 5  private dataPreferences: preferences.Preferences | null = null
 6
 7  /**
 8   * 初始化
 9   * @param context
10   */
11  init(context: Context, storageName: string) {
12    let options: preferences.Options = { name: storageName }
13    this.dataPreferences = preferences.getPreferencesSync(context, options)
14
15    // on就是给数据设置监听效果
16    let observer = (key: string) => {
17      console.log('key:' + key + ', changed')
18      // this.dataPreferences as preferences.Preferences
19      this.dataPreferences?.flush((err: BusinessError) => {
20        if (err) {
21          console.log(`failed to flush, ${err.name}-${err.message}`)
22        } else {
23          console.log('flush success')
24        }
25      })
26    }
27    this.dataPreferences.on('change', observer)
28
29  }
30
31  insertData(key: string, value: string) {
32    if (this.dataPreferences?.hasSync(key)) {
33      console.log('this preferences key is contained')
34    } else {
35      this.dataPreferences?.putSync(key, value)
36      console.log('this preferences add success')
37    }
38  }
39
40  async readData(key: string, value?: string) {
41    let val = await this.dataPreferences?.getSync(key, value ? value : 'default')
42    console.log('this preferences get value is:' + val)
43    return val
44  }
45
46  deleteData(key: string) {
47    this.dataPreferences?.delete(key, (err: BusinessError, rows) => {
48      if (err) {
49        console.log(`failed to delete, ${err.name}-${err.message}`)
50      } else {
51        console.log('delete success')
52      }
53    })
54  }
55}
56
57const preferencesUtil = new PreferencesUtil()
58
59export default preferencesUtil

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 1Button('设置主题').onClick((event: ClickEvent) => {
 2  preferencesUtil.insertData('theme', 'orange')
 3})
 4
 5Button('获取主题').onClick(async (event: ClickEvent) => {
 6  const theme = await preferencesUtil.readData('theme', 'blue')
 7  console.log('get theme:' + theme)
 8})
 9
10Button('删除主题').onClick(async (event: ClickEvent) => {
11  const theme = await preferencesUtil.deleteData('theme')
12  console.log('detele theme:' + theme)
13})

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1this preferences key is contained
2this preferences get value is:pink

初始化

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 1import { AbilityConstant, ConfigurationConstant, UIAbility, Want } from '@kit.AbilityKit';
 2import { hilog } from '@kit.PerformanceAnalysisKit';
 3import { window } from '@kit.ArkUI';
 4import { cardDBUtils } from '../utils/CardDBUtils';
 5import preferencesUtil from '../utils/PreferencesUtils';
 6import kvStore from '../utils/KVStore';
 7
 8const DOMAIN = 0x0000;
 9
10export default class EntryAbility extends UIAbility {
11  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
12    this.context.getApplicationContext().setColorMode(ConfigurationConstant.ColorMode.COLOR_MODE_NOT_SET);
13    hilog.info(DOMAIN, 'testTag', '%{public}s', 'Ability onCreate');
14  }
15
16  onDestroy(): void {
17    hilog.info(DOMAIN, 'testTag', '%{public}s', 'Ability onDestroy');
18  }
19
20  onWindowStageCreate(windowStage: window.WindowStage): void {
21    // 加载数据库
22    cardDBUtils.initCardDB(this.context, 'goodcard')
23    preferencesUtil.init(this.context, 'goodMail')
24    // preferencesUtil.insertData('theme', 'pink')
25    kvStore.init(this.context)
26....

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