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
CODE
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`);
}
});
2. File system space detection
CODE
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: ${free / 1024 / 1024} MB`);
});
});
};
3. Large file scanning (recursively traverse directory)
CODE
import { File } from '@ohos.file';
async function scanLargeFiles(dir: string, threshold = 10 * 1024 * 1024) {
const files = await File.list(dir);
for (const file of files) {
const filePath = `${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`);
}
}
}
}
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
CODE
// 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
}
3. Database optimization
CODE
// SQLite database compression (clean up idle pages)
import { Database } from '@ohos.sqlite';
const db = Database.open('app.db');
db.execSQL('VACUUM;'); // Compress database file
5. Monitoring and early warning: "alarm" that stores health 🚨
1. Threshold warning mechanism
CODE
// 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');
}
});
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
Statistical Analysis: UsestorageStatisticsto locate large users
Strategic optimization: Optimize by "cache grading + data compression + database slimming" combination
Dynamic monitoring: Set threshold warning, automatically/manually free space
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