diff --git a/app/build.gradle b/app/build.gradle
index 898068b40..861dea5fb 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply from: 'quality.gradle'
 
 dependencies {
     compile ('com.github.nicolas-raoul:Quadtree:211b6fe59ac48f') {
diff --git a/app/quality.gradle b/app/quality.gradle
new file mode 100644
index 000000000..e4cdd64e7
--- /dev/null
+++ b/app/quality.gradle
@@ -0,0 +1,23 @@
+apply plugin: 'checkstyle'
+
+check.dependsOn 'checkstyle'
+
+checkstyle {
+    toolVersion = '7.5.1'
+}
+
+task checkstyle(type: Checkstyle) {
+    configFile file("${project.rootDir}/script/style/checkstyle.xml")
+    source 'src'
+    include '**/*.java'
+    exclude '**/gen/**'
+
+    classpath = files()
+
+    reports {
+        html {
+            enabled true
+            destination "$project.buildDir/reports/checkstyle/checkstyle.html"
+        }
+    }
+}
diff --git a/script/style/checkstyle.xml b/script/style/checkstyle.xml
new file mode 100644
index 000000000..baebde870
--- /dev/null
+++ b/script/style/checkstyle.xml
@@ -0,0 +1,222 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+    "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+    "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+
+<!--
+    Modified from https://github.com/checkstyle/checkstyle/blob/master/src/main/resources/google_checks.xml.
+    Modifications are:
+    - doubled each value in Indentation
+
+    Checkstyle configuration that checks the Google coding conventions from Google Java Style
+    that can be found at https://google.github.io/styleguide/javaguide.html.
+
+    Checkstyle is very configurable. Be sure to read the documentation at
+    http://checkstyle.sf.net (or in your downloaded distribution).
+
+    To completely disable a check, just comment it out or delete it from the file.
+
+    Authors: Max Vetrenko, Ruslan Diachenko, Roman Ivanov.
+ -->
+
+<module name = "Checker">
+    <property name="charset" value="UTF-8"/>
+
+    <property name="severity" value="warning"/>
+
+    <property name="fileExtensions" value="java, properties, xml"/>
+    <!-- Checks for whitespace                               -->
+    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
+    <module name="FileTabCharacter">
+        <property name="eachLine" value="true"/>
+    </module>
+
+    <module name="TreeWalker">
+        <module name="OuterTypeFilename"/>
+        <module name="IllegalTokenText">
+            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL"/>
+            <property name="format" value="\\u00(09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)"/>
+            <property name="message" value="Consider using special escape sequence instead of octal value or Unicode escaped value."/>
+        </module>
+        <module name="AvoidEscapedUnicodeCharacters">
+            <property name="allowEscapesForControlCharacters" value="true"/>
+            <property name="allowByTailComment" value="true"/>
+            <property name="allowNonPrintableEscapes" value="true"/>
+        </module>
+        <module name="LineLength">
+            <property name="max" value="100"/>
+            <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
+        </module>
+        <module name="AvoidStarImport"/>
+        <module name="OneTopLevelClass"/>
+        <module name="NoLineWrap"/>
+        <module name="EmptyBlock">
+            <property name="option" value="TEXT"/>
+            <property name="tokens" value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
+        </module>
+        <module name="NeedBraces"/>
+        <module name="LeftCurly">
+            <property name="maxLineLength" value="100"/>
+        </module>
+        <module name="RightCurly">
+            <property name="id" value="RightCurlySame"/>
+            <property name="tokens" value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_DO"/>
+        </module>
+        <module name="RightCurly">
+            <property name="id" value="RightCurlyAlone"/>
+            <property name="option" value="alone"/>
+            <property name="tokens" value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT"/>
+        </module>
+        <module name="WhitespaceAround">
+            <property name="allowEmptyConstructors" value="true"/>
+            <property name="allowEmptyMethods" value="true"/>
+            <property name="allowEmptyTypes" value="true"/>
+            <property name="allowEmptyLoops" value="true"/>
+            <message key="ws.notFollowed"
+                     value="WhitespaceAround: ''{0}'' is not followed by whitespace. Empty blocks may only be represented as '{}' when not part of a multi-block statement (4.1.3)"/>
+            <message key="ws.notPreceded"
+                     value="WhitespaceAround: ''{0}'' is not preceded with whitespace."/>
+        </module>
+        <module name="OneStatementPerLine"/>
+        <module name="MultipleVariableDeclarations"/>
+        <module name="ArrayTypeStyle"/>
+        <module name="MissingSwitchDefault"/>
+        <module name="FallThrough"/>
+        <module name="UpperEll"/>
+        <module name="ModifierOrder"/>
+        <module name="EmptyLineSeparator">
+            <property name="allowNoEmptyLineBetweenFields" value="true"/>
+        </module>
+        <module name="SeparatorWrap">
+            <property name="id" value="SeparatorWrapDot"/>
+            <property name="tokens" value="DOT"/>
+            <property name="option" value="nl"/>
+        </module>
+        <module name="SeparatorWrap">
+            <property name="id" value="SeparatorWrapComma"/>
+            <property name="tokens" value="COMMA"/>
+            <property name="option" value="EOL"/>
+        </module>
+        <module name="PackageName">
+            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
+            <message key="name.invalidPattern"
+                     value="Package name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="TypeName">
+            <message key="name.invalidPattern"
+                     value="Type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="MemberName">
+            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
+            <message key="name.invalidPattern"
+                     value="Member name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="ParameterName">
+            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+            <message key="name.invalidPattern"
+                     value="Parameter name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="CatchParameterName">
+            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+            <message key="name.invalidPattern"
+                     value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="LocalVariableName">
+            <property name="tokens" value="VARIABLE_DEF"/>
+            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+            <message key="name.invalidPattern"
+                     value="Local variable name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="ClassTypeParameterName">
+            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+            <message key="name.invalidPattern"
+                     value="Class type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="MethodTypeParameterName">
+            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+            <message key="name.invalidPattern"
+                     value="Method type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="InterfaceTypeParameterName">
+            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+            <message key="name.invalidPattern"
+                     value="Interface type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="NoFinalizer"/>
+        <module name="GenericWhitespace">
+            <message key="ws.followed"
+                     value="GenericWhitespace ''{0}'' is followed by whitespace."/>
+            <message key="ws.preceded"
+                     value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
+            <message key="ws.illegalFollow"
+                     value="GenericWhitespace ''{0}'' should followed by whitespace."/>
+            <message key="ws.notPreceded"
+                     value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
+        </module>
+        <module name="Indentation">
+            <property name="basicOffset" value="4"/>
+            <property name="braceAdjustment" value="0"/>
+            <property name="caseIndent" value="4"/>
+            <property name="throwsIndent" value="8"/>
+            <property name="lineWrappingIndentation" value="8"/>
+            <property name="arrayInitIndent" value="4"/>
+        </module>
+        <module name="AbbreviationAsWordInName">
+            <property name="ignoreFinal" value="false"/>
+            <property name="allowedAbbreviationLength" value="1"/>
+        </module>
+        <module name="OverloadMethodsDeclarationOrder"/>
+        <module name="VariableDeclarationUsageDistance"/>
+        <module name="CustomImportOrder">
+            <property name="sortImportsInGroupAlphabetically" value="true"/>
+            <property name="separateLineBetweenGroups" value="true"/>
+            <property name="customImportOrderRules" value="STATIC###THIRD_PARTY_PACKAGE"/>
+        </module>
+        <module name="MethodParamPad"/>
+        <module name="ParenPad"/>
+        <module name="OperatorWrap">
+            <property name="option" value="NL"/>
+            <property name="tokens" value="BAND, BOR, BSR, BXOR, DIV, EQUAL, GE, GT, LAND, LE, LITERAL_INSTANCEOF, LOR, LT, MINUS, MOD, NOT_EQUAL, PLUS, QUESTION, SL, SR, STAR, METHOD_REF "/>
+        </module>
+        <module name="AnnotationLocation">
+            <property name="id" value="AnnotationLocationMostCases"/>
+            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF"/>
+        </module>
+        <module name="AnnotationLocation">
+            <property name="id" value="AnnotationLocationVariables"/>
+            <property name="tokens" value="VARIABLE_DEF"/>
+            <property name="allowSamelineMultipleAnnotations" value="true"/>
+        </module>
+        <module name="NonEmptyAtclauseDescription"/>
+        <module name="JavadocTagContinuationIndentation"/>
+        <module name="SummaryJavadoc">
+            <property name="forbiddenSummaryFragments" value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
+        </module>
+        <module name="JavadocParagraph"/>
+        <module name="AtclauseOrder">
+            <property name="tagOrder" value="@param, @return, @throws, @deprecated"/>
+            <property name="target" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
+        </module>
+        <module name="JavadocMethod">
+            <property name="scope" value="public"/>
+            <property name="allowMissingParamTags" value="true"/>
+            <property name="allowMissingThrowsTags" value="true"/>
+            <property name="allowMissingReturnTag" value="true"/>
+            <property name="minLineCount" value="2"/>
+            <property name="allowedAnnotations" value="Override, Test"/>
+            <property name="allowThrowsTagsForSubclasses" value="true"/>
+        </module>
+        <module name="MethodName">
+            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
+            <message key="name.invalidPattern"
+                     value="Method name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="SingleLineJavadoc">
+            <property name="ignoreInlineTags" value="false"/>
+        </module>
+        <module name="EmptyCatchBlock">
+            <property name="exceptionVariableName" value="expected"/>
+        </module>
+        <module name="CommentsIndentation"/>
+    </module>
+</module>