一个Android库提供了常用工具和实用程序

一个Android库提供了常用工具和实用程序

Toolbelt is an Android library for common tools and utilities for optional values, easier logging and operations on Strings. I need these mostly boilerplate stuff for almost all of my Android projects so I decided to serve them as a library.

How to Include In Your Project?

Toolbelt is served on Bintray and jCenter. So, simply add following

compile 'com.github.mehmetakiftutuncu:toolbelt:latestVersion'

inside dependencies in build.gradle file in your application module. If somehow dependency resolution fails, you should also add the following repository

maven {url 'https://dl.bintray.com/mehmetakiftutuncu/maven'}

inside repositories. Don't forget to replace latestVersion with the latest version number found in the title.

What's In It?

1. Optional

It represents an optional value that may or may not exist. This is an attempt to avoid using nulls as they are not safe.

// Creates an existing optionalOptional optional1 = Optional.with("Hello"); // Short for Optional.with();// Creates an empty optionalOptional optional2 = Optional.empty(); // Short for Optional.empty();// Also creates an empty optional if the passed value is nullOptional> optional3 = Optional.with(null);optional1.get(); // Yields "Hello"optional2.get(); // Throws a NoSuchElementException because value does not existoptional1.getOrElse("World"); // Yields "Hello"optional3.getOrElse("World"); // Yields "World"optional1.isDefined(); // Yields trueoptional2.isDefined(); // Yields falseoptional1.isEmpty(); // Yields falseoptional2.isEmpty(); // Yields trueOptional alternative = Optional.with("World");optional1.or(alternative); // Yields optional1 itself because value exists in optional1optional2.or(alternative); // Yields passed alternative because value does not exist in optional2// Here is an example use case below that extracts the extension of from a file name.// Instead of using getExtensionUnsafe dealing with null values, use getExtensionSafe// so whoever calls it will know if extension exists or not without dealing with nulls.// Of course this is just a demonstration, these methods could have been improved greatly.public String getExtensionUnsafe(String fileName) { if (fileName == null) return null; String[] parts = fileName.split("\\."); return (parts.length == 0) ? null : parts[parts.length - 1]; }public Optional getExtensionSafe(String fileName) { String[] parts = Optional.with(fileName).getOrElse("").split("\\."); return (parts.length == 0) ? Option.empty() : Optional.with(parts[parts.length - 1]);}

2. Log

It wraps android.util.Log methods to get dynamic tags using the caller reference and supports message formatting as done in String.format(). It also simplifies log levels to just DEBUG, WARN and ERROR.

// Debug level log methodspublic static void debug(String tag, String message, Object... args)public static void debug(Class caller, String message, Object... args)// Warn level log methodspublic static void warn(String tag, String message, Object... args)public static void warn(Class caller, String message, Object... args)// Error level log methods with and without a Throwablepublic static void error(String tag, String message, Object... args)public static void error(String tag, Throwable throwable, String message, Object... args)public static void error(Class caller, String message, Object... args)public static void error(Class caller, Throwable throwable, String message, Object... args)/* Example call with dynamic tag from a non-static scope where 'this' is accessible, for example in an instance method of class Foo * * This would log following with debug level: * * Tag | Message * ----|-------- * Foo | Doing some work with 'test' and '123'... */Log.debug(this, "Doing some work with '%s' and '%d'...", "test", 123);/* Example call with dynamic tag from a static scope where 'this' is inaccessible, for example in a static method of class Bar * * This would log following with warn level: * * Tag | Message * ----|-------- * Bar | Doing some work with 'test' and '123'... */Log.warn(Bar.class, "Doing some work with '%s' and '%d'...", "test", 123);

3. StringUtilities

Name says it all.

StringUtilities.isEmpty(null); // Yields trueStringUtilities.isEmpty(""); // Yields trueStringUtilities.isEmpty("foo"); // Yields falseList list = new ArrayList<>();list.add("foo");list.add("bar");list.add("baz");// These methods work on any collection extending java.util.CollectionStringUtilities.makeString(list, "['", "', '", "']"); // Yields: "['foo', 'bar', 'baz']"StringUtilities.makeString(list, ", "); // Yields: "foo, bar, baz"

4. Timer

You can use it to time stuff and see how long they take to run.

// Manage start and stop yourselfTimer.start("foo");// Do some worklong duration = Timer.stop("foo");printf("Finished in %d milliseconds!", duration);// Or wrap a block of work and time it automaticallyTimer.ActionResult piResult = Timer.time(new Timer.Action() { @Override public Double perform() { // Perform some advanced math here to calculate the value of PI return 3.14; }});printf("Calculated PI as %f and it took %d milliseconds!", piResult.result, piResult.duration);

Contribution

Please feel free to and contribute. I'd love to hear your feedback, issue reports and pull requests.

License

Toolbelt is licensed under Apache License Version 2.0.

Copyright (C) 2016 Mehmet Akif TütüncüLicensed 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 athttp://apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed 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 andlimitations under the License.

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