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A small collection of Android utility classes, written in Kotlin and callable from Java. Version 2.0.0 is a rewrite: classes that the Android framework, AndroidX or the Kotlin standard library already cover were removed, the rest were rewritten for current Android and covered with unit tests.

Download the sample APK

Contents

All sources live in common/src/main/kotlin/com/wx/android/common.

Area	Classes
App and device	AppUtils, DeviceUtils, DisplayUtils, MemoryUtils, NetworkUtils, TelephonyUtils
System features	ClipboardUtils, InputMethodUtils, IntentUtils, NotificationUtils, ShortcutUtils, ToastUtils, VibratorUtils, WindowUtils
Images and views	BitmapUtils, BitmapFilters, AnimatorUtils, ClickUtils, ViewUtils, PictureView, CommonEditText, Colors
Data and text	CalendarUtils, DigestUtils, FileUtils, ResourceUtils, ThreadUtils, UrlUtils, VerifyUtils

The sample app has a home page (device and app info) and five demo pages: bitmap filters, verification and digests, system features, views and animation, and a calendar.

ScreenShot

Home	Dark mode	Bitmap filters	Verify & digests

System features	Views & animation	PictureView	Calendar

Usage

Gradle:

1. Add the JitPack repository to settings.gradle:

dependencyResolutionManagement {
    repositories {
        google()
        mavenCentral()
        maven { url = 'https://jitpack.io' }
    }
}

2. Add the dependency to your module's build.gradle:

implementation 'com.github.venshine:AndroidCommon:2.0.0'

Gradle Kotlin DSL:

// settings.gradle.kts
dependencyResolutionManagement {
    repositories {
        google()
        mavenCentral()
        maven("https://jitpack.io")
    }
}

// build.gradle.kts
implementation("com.github.venshine:AndroidCommon:2.0.0")

The old coordinate com.wx.android.common:common:1.0.1 can no longer be downloaded. The package name com.wx.android.common is unchanged. The library is written in Kotlin, so it adds kotlin-stdlib to your project. It has no other runtime dependency (no AndroidX, no Gson). minSdk is 21.

Demo

Every utility is an object with @JvmStatic methods, so the call looks the same in Kotlin and Java.

Kotlin:

import com.wx.android.common.util.*

val md5 = DigestUtils.md5("hello")                     // 5d41402abc4b2a76b9719d911017c592
val ok = VerifyUtils.isIdCard("11010519491231002X")    // true
val size = FileUtils.formatSize(1536)                  // "1.50KB"
val dp = DisplayUtils.dip2px(context, 16f)
ClipboardUtils.copy(context, "text")
ThreadUtils.execute { /* work in the background */ }

Java:

import com.wx.android.common.util.DigestUtils;
import com.wx.android.common.util.VerifyUtils;

String md5 = DigestUtils.md5("hello");
boolean ok = VerifyUtils.isIdCard("11010519491231002X");

Permissions

The library manifest declares no permission. Declare the ones your app needs for the classes you call:

Permission	Needed by
ACCESS_NETWORK_STATE	NetworkUtils.isNetworkAvailable, NetworkUtils.getDNS*
VIBRATE	VibratorUtils
CALL_PHONE	IntentUtils.call (without it the method returns false)
SYSTEM_ALERT_WINDOW and the user's "display over other apps" grant	WindowUtils.addView (without it the method returns false)
WRITE_SETTINGS and the user's grant in system settings	DeviceUtils.setScreenBrightness, setScreenBrightnessMode, setScreenDormantTime (without it they return false)
POST_NOTIFICATIONS (runtime permission on newer Android versions)	NotificationUtils.create (without it the method returns false)
REQUEST_DELETE_PACKAGES	AppUtils.uninstall on newer Android versions
<queries> or QUERY_ALL_PACKAGES	AppUtils methods that look at other apps: newer Android versions only show a limited set of installed apps

Behavior you should know about

• Methods that can fail because of a missing app, permission or system support return false / null instead of throwing.
• ToastUtils needs one ToastUtils.init(context) call, for example in Application.onCreate. On newer Android versions text toasts ignore custom gravity and offsets.
• ClipboardUtils: newer Android versions restrict clipboard reads (background reads are refused, foreground reads may show a system notice), so getText can return null even when the clipboard has content.
• VerifyUtils.isMobileNumber only checks the format ^1[3-9]\d{9}$. It does not check whether the number segment is actually assigned.
• VerifyUtils.isIdCard validates an 18-digit Chinese resident ID number: digits, a real birth date that is not in the future, and the check code per GB 11643-1999. It does not check the region code and does not support 15-digit numbers.
• DigestUtils.md5 and sha1 are for checksums and cache keys only. They are broken for security purposes; use sha256 or a password hashing function.
• BitmapFilters works pixel by pixel on the CPU. Run it off the main thread for large images.

Migrating from 1.x

2.0.0 is not source compatible with 1.x. Everything below was removed or changed.

Removed: use the replacement

1.x	2.0.0 replacement
ArrayUtils, CollectionUtils, MapUtils, ObjectUtils	Kotlin standard library: isNullOrEmpty(), joinToString(), toList() / toSet() / toTypedArray(), entries.firstOrNull { ... }, ==
StringUtils.isEmpty / equals / isNumeric / toLowerCase / toUpperCase	isNullOrEmpty(), ==, all(Char::isDigit), lowercase() / uppercase()
StringUtils.encodeString / decodeString	UrlUtils.encode / decode
BASE64Utils	android.util.Base64
MD5Utils.encodeMD5 / encodeMD52	DigestUtils.md5 (checksums only)
SHA1Utils.SHA1 / toHexString	DigestUtils.sha1, DigestUtils.toHex; prefer DigestUtils.sha256
ByteUtils, SerializableUtils	Parcelable, kotlinx.serialization or JSON. Java object serialization on untrusted data is unsafe
JsonUtils	kotlinx.serialization, Moshi or Gson, added by your app (Gson is no longer a transitive dependency)
AssetsUtils.getTextFromAssets / getTextFromAssets2	ResourceUtils.getTextFromAssets
AssetsUtils.getFileFromAssets, AssetsUtils.parseJsonTo*	context.assets.open(name) and your JSON library
IOUtils.close	Closeable.use { }
PropertyUtils.getPropertyValue	java.util.Properties().apply { load(stream) }.getProperty(key)
NumberUtils.*	String.format(Locale, ...), BigDecimal.setScale, DecimalFormat
RandomUtils.*	kotlin.random.Random, List.shuffled(), java.security.SecureRandom
CommonUtils.generateId	View.generateViewId() or an AtomicInteger
LogUtils.d / e	android.util.Log or Timber
ReflectUtils.*	Removed. Newer Android versions restrict reflection on hidden APIs, so the helper is not offered any more
ShellUtils.*	Removed. Use a dedicated root library if you need it
SystemUtils.*	Build.BRAND, Build.MODEL, Build.VERSION.SDK_INT, Build.SUPPORTED_ABIS, ...
CpuUtils.*	Runtime.getRuntime().availableProcessors(), Build.SUPPORTED_ABIS
ServiceUtils.isServiceRunning / stopRunningService	Removed. ActivityManager.getRunningServices only returns your own services since Android 8.0
SharedPreferencesUtils.*	Jetpack DataStore, or SharedPreferences.edit { } (androidx.core)
HandlerUtils.runOnUiThread / runOnUiThreadDelay / removeRunable	ThreadUtils.runOnUiThread / runOnUiThreadDelayed / removeCallbacks
FragmentUtils.*	FragmentManager.commit { } (androidx.fragment)
CameraUtils.openCamera, IntentUtils.takeCamera	ActivityResultContracts.TakePicture (or IntentUtils.openCamera to just open the camera app)
ImageUtils.openPicture, IntentUtils.choosePhoto	ActivityResultContracts.PickVisualMedia / GetContent
BlurUtils.fastBlur	RenderEffect.createBlurEffect on Android 12+, or an image library
ScrollListView, ScrollGridView, ViewUtils.get/setListViewHeight, get/setGridViewHeight	RecyclerView inside NestedScrollView
WebActivity	Custom Tabs (androidx.browser) or your own WebView screen
CommonCfg	Removed (it was an empty class)
TimeUtils.getCurrentTime / getCurrentTimeMillis and its %Y-style constants	CalendarUtils.getTime(millis, pattern) with SimpleDateFormat patterns, System.currentTimeMillis()

Removed because Android no longer allows it

1.x	Why
TelephonyUtils.getIMEI / getIMSI / getSimSerialNumber / getLine1Number	IMEI and serial number need the privileged READ_PRIVILEGED_PHONE_STATE permission since Android 10, which third-party apps cannot get (Android 10 privacy changes); getDeviceId has been deprecated since API 26 (TelephonyManager). Use an app-generated UUID if you need an installation id
TelephonyUtils.getCallState / getDataActivity / getDataState / getNetworkType	Need READ_PHONE_STATE and are restricted on newer Android versions; use TelephonyCallback in your app
DeviceUtils.getUUID	Built from IMEI and SIM serial (see above); generate and store your own UUID
DeviceUtils.getAirplaneMode / setAirplaneMode / isAirplaneModeOpen	Third-party apps cannot change the airplane mode setting on current Android versions
DeviceUtils.getBluetoothState / setBluetooth / isBluetoothOpen	BluetoothAdapter.enable() is deprecated since API 33 and always fails for apps targeting it (BluetoothAdapter)
NetworkUtils.getWlanMacAddress / getEthernetMacAddress	WifiInfo.getMacAddress() returns the constant 02:00:00:00:00:00 since Android 6.0 (Android 6.0 changes); Android 10 randomizes MAC addresses by default
NetworkUtils.getWlanGateway / getWlanMask / getEthernetGateway / getEthernetMask	Read system properties through getprop, which is not a supported interface; use ConnectivityManager.getLinkProperties
AppUtils.isAppInBackground	Used getRunningTasks, which is no longer available to third-party apps since API 21 (ActivityManager). Use ProcessLifecycleOwner (androidx.lifecycle)
PackageUtils.install, PackageUtils.getAllApps	Installing needs a FileProvider URI and REQUEST_INSTALL_PACKAGES, which the library cannot configure for you; listing other apps is limited by package visibility on newer Android versions

Moved or changed

1.x	2.0.0
PackageUtils.*	Merged into AppUtils: isInstalled (was isInsatalled), isSystemApp (was isSystemApplication), startApp, checkPermission, uninstall, getInstalledPackages (was getInsatalledPackageInfos)
AppUtils.getVersionCode, getAppVersionCode	Return Long (the long version code), -1 for a missing package
AppUtils.getAppSignature	AppUtils.getAppSignatures (list of certificates) and getAppSignatureSha256
AppUtils.isApkDebugable	AppUtils.isApkDebuggable(context, packageName)
CleanUtils.*	FileUtils.cleanInternalCache / cleanExternalCache / cleanFiles / cleanDatabases / cleanSharedPreferences / cleanCustomCache / cleanApplicationDatas. The old cleanDatabases / cleanSharedPreferences pointed to a wrong directory and did nothing
FileUtils.getFolderSize	Same name, no longer throws a checked exception
FileUtils copy / move / delete / read / write / name helpers	Kotlin File extensions (copyTo, readText, deleteRecursively, extension, ...). FileUtils.moveFile(src, dest) stays
MemoryUtils.getFormatSize	FileUtils.formatSize(Long)
MemoryUtils.getTotalMemory / getAvailableMemory / getAllMemory	getTotalMemory(context) / getAvailableMemory(context) return bytes as Long (they returned formatted strings)
MemoryUtils.*ExternalMemorySize()	Take a Context, measure the app-specific external directory, return -1 when unavailable. isExternalMemoryFull is removed
ShortcutUtils.addShortCut / deleteShortCut / hasShortCut	ShortcutUtils.requestPin(...), API 26+ only (returns false below). The INSTALL_SHORTCUT broadcast has had no effect since Android 8.0 (Android 8.0 changes)
NotificationUtils.create(...)	New signature create(context, id, title, content, smallIcon, pendingIntent?, ongoing, autoCancel, largeIcon, channelId); creates a notification channel automatically and returns false without POST_NOTIFICATIONS
NotificationUtils.getPendingIntentFor*	Parameters reordered (context, intent, flags, requestCode); FLAG_IMMUTABLE is added by default
IntentUtils.*	Same names (except the camera / photo ones above); all return Boolean, the missing-app and permission cases no longer throw
InputMethodUtils.toggleSoftInput	Removed (deprecated by the platform); use showSoftInput / hideSoftInput
ToastUtils.showToast(String, ...)	showToast(CharSequence, ...); showToastAlways and hideToast are removed (they relied on private Toast fields), cancel() replaces hideToast
ThreadUtils.execute / submit / shutdown / getUIThreadId	Same names. The pool queues tasks instead of silently dropping them when it is full
VibratorUtils.*	Same names; uses VibrationEffect / VibratorManager on newer systems
WindowUtils.addView	Returns false without the overlay permission; uses TYPE_APPLICATION_OVERLAY
ResourceUtils	Only getResourceByName, getTextFromAssets, getRawText remain. Use Context.getString, getColor, getDrawable, ... for the rest
DeviceUtils setters	Return false when WRITE_SETTINGS is not granted instead of throwing
DisplayUtils.getStatusBarHeight2, getTitleBarHeight	Removed; getStatusBarHeight reads the window insets and falls back to the system resource
URLParse	UrlUtils.parse(url), returns a ParsedUrl data class
UrlUtils.encode / decode	Same names, no checked exception; decode returns the input if it is malformed
VerifyUtils.isChineseCard	VerifyUtils.isIdCard (full check, see above). 15-digit numbers are no longer accepted
VerifyUtils.isMobileNumber	Pattern is now ^1[3-9]\d{9}$ (the old one rejected most current number segments)
VerifyUtils.isEmail / isEmail2 / isUrl	android.util.Patterns.EMAIL_ADDRESS / Patterns.WEB_URL
VerifyUtils.isNumber / isLetter / isNumberAndLetter / isPostCode	Removed (all(Char::isDigit), ...)
CalendarUtils	isToday / isYesterday now check both ends of the day (before, any later time counted as today); TIME_FORMAT ends with milliseconds (SSS)
BitmapUtils filters (convertGreyImg, adjustTone, nostalgic, soften, sunshine, film, sharpen, emboss, saturation, lum, hue, lumAndHueAndSaturation)	Moved to BitmapFilters. They now return ARGB_8888 bitmaps and keep alpha; film also inverts the border pixels, hue is a real hue rotation, lumAndHueAndSaturation applies all three adjustments, sharpen keeps flat areas unchanged
BitmapUtils.convertToBlackWhite	Same code as convertGreyImg; use BitmapFilters.convertGreyImg
BitmapUtils.resToDrawable, bitmapToByte, byteToBitmap, bitmapToDrawable, drawableToByte, byteToDrawable	Context.getDrawable, Bitmap.compress, BitmapFactory.decodeByteArray, BitmapDrawable
BitmapUtils.screenshot, decodeBitmap(Bitmap, format, quality), compressBitmap(Bitmap, double), scale(Bitmap, double, double)	Removed (screenshot used the deprecated drawing cache; compressBitmap(Bitmap, double) never changed anything; use zoom for an exact size)
BitmapUtils.compressBitmap(Bitmap)	compressBitmap(Bitmap, maxKb = 100), stops at quality 10 instead of crashing
BitmapUtils.createWatermarkBitmap	Watermark sits inside the bottom-right corner; optional padding
AnimatorUtils.*	Same names; every method returns the started ObjectAnimator
ClickUtils.clickMultiple	Same signature; the count is kept per view (the old one used static fields shared by all views)
ClipboardUtils.getText	Returns String?
Colors	object Colors with const val; the @ColorInt annotation is gone (no AndroidX dependency)
ViewUtils.getTextViewHeight, findTextView	Same names; findTextView no longer crashes on an empty ViewGroup
PictureView, CommonEditText	Same names and listeners; PictureView ignores non-bitmap drawables instead of crashing
TelephonyUtils (rest), NetworkUtils.isNetworkAvailable / getLocalIPv4 / getLocalIPv6 / getDNS1 / getDNS2	Kept (getDNS1/2 now take a Context; return String?)

Maintenance status

The project is maintained at a low pace: bug fixes and compatibility updates, no large new features. Issues and pull requests are welcome.

Local checks: ./gradlew :common:testDebugUnitTest :common:assembleRelease :sample:assembleDebug :sample:testDebugUnitTest. The tests run on Robolectric with a fixed SDK 35 and on the plain JVM. The sample app has been walked through page by page on a real device running Android 17.

Author

• Email: venshine.cn@gmail.com

Credits

The sample app bundles these fonts, both licensed under the SIL Open Font License 1.1 (license texts in sample/licenses/):

• Space Grotesk: Copyright 2020 The Space Grotesk Project Authors
• JetBrains Mono: Copyright 2020 The JetBrains Mono Project Authors

The library itself bundles no fonts.

License

Copyright (C) 2015 venshine.cn@gmail.com

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.