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Hongmeng application file space statistics and management: unleashing storage potential 💾

Hongmeng Next provides accurate file space management capabilities to help developers monitor storage usage in real time.This article analyzes core interfaces, statistical methods and optimization strategies~

1. Core capabilities: "Digital Dashboard" for space management📊

Hongmeng realizes fine storage management through two major modules:

  • @ohos.file.statvfs: Get file system-level data (total space/remaining space/number of nodes)
  • @ohos.file.storageStatistics: Get application-level data (installation package/cache/user data size)

2. Key interface quick lookup table🚀

Functions Interface/Methods Return Value Type Sample Uses
Get application storage statistics storageStatistics.getCurrentBundleStats() BundleStats Statistics installation package (appSize), cache (cacheSize)
Get file system space statvfs.getFreeSize(path) number (bytes) Detect the remaining space of filesDir
Traversal directory size File.traverseDir(dirPath, callback) - Recursively calculate all file sizes in the directory

3. Practical combat: Spatial statistics code example 📈

1. Application storage details statistics 

import { storageStatistics } from '@ohos.file.storageStatistics';  

// Get application installation package, cache, data size
storageStatistics.getCurrentBundleStats((err, stats) => {  
  if (!err) {  
console.log(`install package size: ${stats.appSize / 1024 / 1024} MB`);
console.log(`Cache Size: ${stats.cacheSize / 1024 / 1024} MB`);
console.log(`User data size: ${stats.dataSize / 1024 / 1024} MB`);
  }  
});
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2. File system space detection 

import { statvfs } from '@ohos.file.statvfs';  
import { getContext } from '@ohos.app.ability';  

const checkStorage = () => {  
  const context = getContext() as common.UIAbilityContext;  
const filesPath = context.filesDir; // Application private file directory
const cachePath = context.cacheDir; // Cache directory

// Detect the total and remaining space of the file system
  statvfs.getTotalSize(filesPath, (err, total) => {  
    statvfs.getFreeSize(filesPath, (err, free) => {  
console.log(`Total file system space: ${total / 1024 / 1024} MB`);
console.log(`Remaining space: ${free / 1024 / 1024} MB`);
    });  
  });  
};
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3. Large file scanning (recursively traverse directory) 

import { File } from '@ohos.file';  

async function scanLargeFiles(dir: string, threshold = 10 * 1024 * 1024) {  
  const files = await File.list(dir);  
  for (const file of files) {  
    const filePath = `${dir}/${file}`;  
    const stats = await File.stat(filePath);  
    if (stats.isDirectory) {  
await scanLargeFiles(filePath, threshold); // Recursive subdirectory
    } else {  
      if (stats.size > threshold) {  
console.log(`Large file discovery: ${filePath}, size: ${stats.size / 1024 / 1024} MB`);
      }  
    }  
  }  
}
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4. Optimization strategy: "combination punch" to free up storage space🎯

1. Three principles of cache management

Strategy Implementation Sample Scenario
Regular Clean Set a timer or listen for low memory events to trigger cleaning Automatically clean up unused cache images every week
Level storage Hot data (high frequency) memory, cold data storage disk Chat emoticon package cache rating
Clean by type Preferential deletion of reconstructable temporary files (such as logs/temp pictures) Clean all files in the temp/ directory

2. Data compression scheme 

// Image compression example (using Tinify library)
import { Tinify } from '@ohos.compression';  

async function compressImage(srcPath, destPath) {  
  const compressedData = await Tinify.compressFile(srcPath, {  
    format: 'webp',  
    quality: 80  
  });  
  await File.writeFile(destPath, compressedData);  
await File.delete(srcPath); // Delete the original image
}
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3. Database optimization 

// SQLite database compression (clean up idle pages)
import { Database } from '@ohos.sqlite';  

const db = Database.open('app.db');  
db.execSQL('VACUUM;'); // Compress database file
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5. Monitoring and early warning: "alarm" that stores health 🚨

1. Threshold warning mechanism 

// Cleanup is triggered when the remaining space is less than 10%
statvfs.getFreeSize(filesPath, (err, free) => {  
  const threshold = total * 0.1;  
  if (free < threshold) {  
cleanCache(); // Call the cleaning function
showToast('Insufficient storage space, cache has been automatically cleaned');
  }  
});
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2. User Boot Policy

  • Show storage usage details on the settings page
  • Provide the "One-click cleaning" button to trigger File.deleteAllCache()
  • Display of large file lists and support manual deletion

Summary: "Three-step method" of space management

  1. Statistical Analysis: Use storageStatistics to locate large users
  2. Strategic optimization: Optimize by "cache grading + data compression + database slimming" combination
  3. Dynamic monitoring: Set threshold warning, automatically/manually free space

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