原文鏈接：https://www.zybuluo.com/Tyhj/note/1144961
當設備儲存有限的時候，定時清理APP數據就很重要了

文件清理

文件清理有幾種方式，一種是判斷文件夾的大小，如果太大了就刪除一部分數據，獲取文件夾的大小，需要遍歷文件夾下面的所有文件來獲取大小，文件多了可能比較耗時

//獲取文件大小
 public static long getFolderSize(File file) throws Exception {   
        long size = 0;   
        try {   
            File[] fileList = file.listFiles();   
            for (int i = 0; i < fileList.length; i++) {   
                // 如果下面還有文件   
                if (fileList[i].isDirectory()) {   
                    size = size + getFolderSize(fileList[i]);   
                } else {   
                    size = size + fileList[i].length();   
                }   
            }   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
        return size;   
    }   

可以根據剩余大小空間來清理文件，比較快

String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            File sdcardDir = Environment.getExternalStorageDirectory();
            StatFs sf = new StatFs(sdcardDir.getPath());
            long blockSize = sf.getBlockSize();
            long availCount = sf.getAvailableBlocks();
            long size = availCount * blockSize / (1024 * 1024);
            LogUtils.e(剩余空間:", size + "MB");
}

當然也可以根據文件的數量來刪除文件

//刪除文件
 private static boolean deleteDir(File dir) {
        if (dir != null && dir.isDirectory()) {  
            String[] children = dir.list();  
            for (int i = 0; i < children.length; i++) {  
                boolean success = deleteDir(new File(dir, children[i]));  
                if (!success) {  
                    return false;  
                }  
            }  
        }  
        return dir.delete();  
    }  

清除數據庫的數據

  public static void cleanDatabases(Context context) {
        deleteFilesByDirectory(new File("/data/data/"
                + context.getPackageName() + "/databases"));
    }

清除SharedPreference數據

public static void cleanSharedPreference(Context context) {
        deleteFilesByDirectory(new File("/data/data/"
                + context.getPackageName() + "/shared_prefs"));
    }

緩存清理

獲取緩存大小

 public static String getTotalCacheSize(Context context) {
  
        //Context.getExternalCacheDir() --> SDCard/Android/data/你的應用包名/cache/目錄，一般存放臨時緩存數據   
        long cacheSize = 0;
        try {
            cacheSize = getFolderSize(context.getCacheDir());
            //Context.getExternalFilesDir() --> SDCard/Android/data/你的應用的包名/files/ 目錄，一般放一些長時間保存的數據
            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                cacheSize += getFolderSize(context.getExternalCacheDir());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return getFormatSize(cacheSize);  
    }  

清除緩存

 public static void clearAllCache(Context context) {  
        deleteDir(context.getCacheDir());  
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {   
            deleteDir(context.getExternalCacheDir());  
            //下面兩句清理webview網頁緩存.但是每次執行都報false,我用的是魅藍5.1的系統，后來發現且/data/data/應用package目錄下找不到database文///件夾 不知道是不是個別手機的問題，  
            context.deleteDatabase("webview.db");      
            context.deleteDatabase("webviewCache.db");  
        }   
    }  

格式化單位

/** 
     * 格式化單位 
     * @param size 
     */  
    public static String getFormatSize(double size) {   
        double kiloByte = size / 1024;   
        if (kiloByte < 1) {   
            return size + "Byte";   
        }   
  
        double megaByte = kiloByte / 1024;   
        if (megaByte < 1) {   
            BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));
            return result1.setScale(2, BigDecimal.ROUND_HALF_UP)   
                    .toPlainString() + "KB";   
        }   
  
        double gigaByte = megaByte / 1024;   
        if (gigaByte < 1) {   
            BigDecimal result2 = new BigDecimal(Double.toString(megaByte));   
            return result2.setScale(2, BigDecimal.ROUND_HALF_UP)   
                    .toPlainString() + "MB";   
        }   
  
        double teraBytes = gigaByte / 1024;   
        if (teraBytes < 1) {   
            BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));   
            return result3.setScale(2, BigDecimal.ROUND_HALF_UP)   
                    .toPlainString() + "GB";   
        }   
        BigDecimal result4 = new BigDecimal(teraBytes);   
        return result4.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString()   
                + "TB";   
    }