用户首选项使用分享,通过@ohos.data.preferences相关接口，完成用户首选项的简单使用。

import dataPreferences from '@ohos.data.preferences'; 
import { BusinessError } from '@ohos.base'; 
​ 
​ 
import { GlobalThis } from '../utils/GlobalThis'; 
​ 
let preferences: dataPreferences.Preferences | null = null; 
​ 
let context = GlobalThis.getInstance().getContext("context")  // 获取context 
try { 
 let options: dataPreferences.Options = { name: 'myStore' }; 
 preferences = dataPreferences.getPreferencesSync(context, options); 
 console.log("testtag success to get preferences"); 
} catch (err) { 
 let code = (err as BusinessError).code; 
 let message = (err as BusinessError).message; 
​ 
 console.error(`testtag Failed to get preferences. Code:${code},message:${message}`); 
}

@Entry 
@Component 
struct Index { 
 @State message: string = 'Hello World'; 
​ 
 build() { 
   Row() { 
     Column() { 
       Button("写入数据") 
        .fontSize(50) 
        .fontWeight(FontWeight.Bold) 
        .onClick(()=>{ 
           try { 
             if (preferences!=null && preferences.hasSync('startup')) { 
               console.info("The key 'startup' is contained."); 
            } else { 
               console.info("The key 'startup' does not contain."); 
               // 此处以此键值对不存在时写入数据为例 
               if (preferences!=null) { 
                 preferences.putSync('startup', 'auto'); 
                 preferences.putSync('startup1', 'auto1'); 
                 preferences.putSync('startup2', 'auto2'); 
                 preferences.putSync('startup3', 'auto3'); 
              } 
            } 
          } catch (err) { 
             let code = (err as BusinessError).code; 
             let message = (err as BusinessError).message; 
             console.error(`testtag Failed to check the key 'startup'. Code:${code}, message:${message}`); 
          } 
        }) 
       Button("读取数据") 
        .fontSize(50) 
        .fontWeight(FontWeight.Bold) 
        .onClick(()=>{ 
           if (preferences != null) { 
             try { 
               let val = preferences.getSync('startup', 'default'); 
               console.info(`testtag Succeeded in getting value of 'startup'. val: ${val}.`); 
            } catch (err) { 
               let code = (err as BusinessError).code; 
               let message = (err as BusinessError).message; 
               console.error(`testtag Failed to get value of 'startup'. Code:${code}, message:${message}`); 
            } 
          } 
        }) 
       Button("删除数据") 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
          .onClick(()=>{ 
            if (preferences != null) { 
              try { 
                preferences.deleteSync('startup1'); 
                console.log("删除数据成功"); 
              } catch (err) { 
                let code = (err as BusinessError).code; 
                let message = (err as BusinessError).message; 
                console.error(`Failed to delete the key 'startup'. Code:${code}, message:${message}`); 
              } 
            } 
          }) 
       Button("数据持久化") 
        .fontSize(50) 
        .fontWeight(FontWeight.Bold) 
        .onClick(()=>{ 
           if (context != null) { 
             console.log("testtag"+context.preferencesDir); 
          } 
           if (preferences != null) { 
             try { 
               preferences.flush((err: BusinessError) => { 
                 if (err) { 
                   console.error(`Failed to flush. Code:${err.code}, message:${err.message}`); 
                   return; 
                } 
                 console.info('Succeeded in flushing.'); 
              }) 
            } catch (err) { 
               let code = (err as BusinessError).code; 
               let message = (err as BusinessError).message; 
               console.error(`Failed to flush. Code:${code}, message:${message}`); 
            } 
          } 
        }) 
    } 
    .width('100%') 
  } 
  .height('100%') 
} 
}