nostra13/Android-Universal-Image-Loader · error · IllegalArgumentException

maxFileCount must be a positive number

Error message

maxFileCount must be a positive number

What it means

ImageLoaderConfiguration.Builder.diskCacheFileCount(int) validates that the maximum number of files kept in the LruDiskCache is strictly positive; a zero or negative file count would prevent any caching and is treated as a configuration bug. Like diskCacheSize, this selects LruDiskCache and warns if a custom diskCache() was already set.

Source

Thrown at library/src/main/java/com/nostra13/universalimageloader/core/ImageLoaderConfiguration.java:451

			return this;
		}

		/** @deprecated Use {@link #diskCacheFileCount(int)} instead */
		@Deprecated
		public Builder discCacheFileCount(int maxFileCount) {
			return diskCacheFileCount(maxFileCount);
		}

		/**
		 * Sets maximum file count in disk cache directory.<br />
		 * By default: disk cache is unlimited.<br />
		 * <b>NOTE:</b> If you use this method then
		 * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiskCache LruDiskCache}
		 * will be used as disk cache. You can use {@link #diskCache(DiskCache)} method for introduction your own
		 * implementation of {@link DiskCache}
		 */
		public Builder diskCacheFileCount(int maxFileCount) {
			if (maxFileCount <= 0) throw new IllegalArgumentException("maxFileCount must be a positive number");

			if (diskCache != null) {
				L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS);
			}

			this.diskCacheFileCount = maxFileCount;
			return this;
		}

		/** @deprecated Use {@link #diskCacheFileNameGenerator(com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator)} */
		@Deprecated
		public Builder discCacheFileNameGenerator(FileNameGenerator fileNameGenerator) {
			return diskCacheFileNameGenerator(fileNameGenerator);
		}

		/**
		 * Sets name generator for files cached in disk cache.<br />
		 * Default value -

View on GitHub (pinned to ba33ec64d0)

Solutions

1. Pass a positive count: diskCacheFileCount(200)
2. Clamp dynamic values: Math.max(1, count)
3. If file-count limiting is unwanted, omit the call entirely (unlimited by default)

Example fix

// before
builder.diskCacheFileCount(prefs.getInt("cache_files", 0)); // throws

// after
builder.diskCacheFileCount(Math.max(1, prefs.getInt("cache_files", 200)));

int count = Math.max(1, configuredFileCount);
builder.diskCacheFileCount(count);

static boolean isValidFileCount(int n) {
    return n > 0;
}

When it happens

Trigger: diskCacheFileCount(0) or negative; a count read from preferences/remote config that was never set and defaults to 0.

Common situations: Settings screen 'max cached files' field left at 0; deserialized config objects with unset int fields defaulting to 0; tests exercising builder validation with edge values.

Related errors

• maxSize <= 0
• maxFileCount <= 0
• valueCount <= 0
• cacheMaxSize argument must be positive number
• cacheMaxFileCount argument must be positive number

AI-assisted analysis of nostra13/Android-Universal-Image-Loader@ba33ec64d0 (2026-08-14). Data as JSON: /api/errors/e9ab3c0eed8cec2e. Report an issue: GitHub.