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PreferencesUtil, Preferences Tool Class

#harmonyos #harmony #arkts

Introduction and description of harmony-utils

harmony-utils A HarmonyOS tool library with rich features and extremely easy to use, with the help of many practical tools, is committed to helping developers quickly build Hongmeng applications. Its encapsulated tools cover APP, device, screen, authorization, notification, inter-thread communication, pop-up frames, toast, biometric authentication, user preferences, taking photos, albums, scanning codes, files, logs, exception capture, characters, strings, numbers, collections, dates, random, base64, encryption, decryption, JSON and other functions, which can meet various development needs.

picker_utils It is a sub-store split by harmony-utils, including PickerUtil, PhotoHelper, and ScanUtil.

Download and install

ohpm i @pura/harmony-utils

ohpm i @pura/picker_utils

  //Global initialization method, initialized in the onCreate method of UIAbility AppUtil.init()
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    AppUtil.init(this.context);
  }
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API methods and usage

init initialization 
 PreferencesUtil.init("my_app_preferences");
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put caches data 
PreferencesUtil.put("id", 10000018);
PreferencesUtil.putSync("name", "张三叁");
PreferencesUtil.putSync("bl_nuv", false);
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get get cached value 
 let id = await PreferencesUtil.get("id", "");
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getString Gets the cached value of type string 
let name1 = await PreferencesUtil.getString("name");
let name2 = PreferencesUtil.getStringSync('name');
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getNumber Gets the cached value of type number 
let id1 = await PreferencesUtil.getNumber("id");
let id2 = PreferencesUtil.getNumberSync('id');
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getBoolean Gets the cached value of boolean type 
let bl1 = await PreferencesUtil.getBoolean("bl_nut");
let bl2 = PreferencesUtil.getBooleanSync('bl_nuv');
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has Check whether the cache instance contains the stored key-value pair of the given key 
let bl1 = await PreferencesUtil.has("id");
let bl2 = PreferencesUtil.hasSync('name');
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delete delete cached value 
PreferencesUtil.delete("id");
PreferencesUtil.deleteSync("name");
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clear clear cache 
PreferencesUtil.clear();
PreferencesUtil.clearSync();
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deletePreferences Removes the specified Preferences instance from the cache. If the Preferences instance has a corresponding persistent file, its persistent file will be deleted at the same time. 
 PreferencesUtil.deletePreferences(getContext(), "SP_PREFERENCES_MSG");
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onChange Subscribe to data change. After the value of the subscribed Key is changed, the callback callback is triggered after the flush method is executed. 
  private callback: Callback<string> = (value) => {
    LogUtil.error("onChange: " + value);
  }

 PreferencesUtil.onChange(callback);
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offChange Unsubscribe to data changes 
 PreferencesUtil.offChange(callback);
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onDataChange precisely subscribes to data changes. Only after the subscribed key value changes, the callback callback is triggered after the flush method is executed. 
  private dataCallback = (data: Record<string, preferences.ValueType>) => {
    for (const keyValue of Object.entries(data)) {
      LogUtil.error("onDataChange: " + keyValue);
    }
  }

  PreferencesUtil.onDataChange(["id", "name"], dataCallback);
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offDataChange Cancel the exact subscription data change 
PreferencesUtil.offDataChange(["id", "name"], dataCallback);
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