Add main activity detector and tests.

- Created MainActivityDetector: Checks for a main activity in `AndroidManifest.xml`
- Created ManifestConstants: Manifest Constant definition class
- Created MyIssueRegistry: The issue registry for the linter
- Created tests for the detector
- Created README with overview and instructions

Bug: 21813374
Change-Id: Ia87e6fb3ddbddee744a520deeed39651149caa7a

Author: grant

.gitignore

@@ -0,0 +1,34 @@
+#built application files
+*.apk
+*.ap_
+
+# files for the dex VM
+*.dex
+
+# Java class files
+*.class
+
+# generated files
+bin/
+gen/
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Windows thumbnail db
+Thumbs.db
+
+# OSX files
+.DS_Store
+
+# Eclipse project files
+.classpath
+.project
+
+# Android Studio
+.idea
+*.iml
+
+#.idea/workspace.xml - remove # and delete .idea if it better suit your needs.
+.gradle
+build/

CONTRIBUTING.md

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+# How to become a contributor and submit your own code
+
+## Contributor License Agreements
+
+We'd love to accept your sample apps and patches! Before we can take them, we
+have to jump a couple of legal hurdles.
+
+Please fill out either the individual or corporate Contributor License Agreement
+(CLA).
+
+  * If you are an individual writing original source code and you're sure you
+    own the intellectual property, then you'll need to sign an [individual CLA]
+    (https://developers.google.com/open-source/cla/individual).
+  * If you work for a company that wants to allow you to contribute your work,
+    then you'll need to sign a [corporate CLA]
+    (https://developers.google.com/open-source/cla/corporate).
+
+Follow either of the two links above to access the appropriate CLA and
+instructions for how to sign and return it. Once we receive it, we'll be able to
+accept your pull requests.
+
+## Contributing A Patch
+
+1. Submit an issue describing your proposed change to the repo in question.
+1. The repo owner will respond to your issue promptly.
+1. If your proposed change is accepted, and you haven't already done so, sign a
+   Contributor License Agreement (see details above).
+1. Fork the desired repo, develop and test your code changes.
+1. Ensure that your code adheres to the existing style in the sample to which
+   you are contributing. Refer to the
+   [Google Cloud Platform Samples Style Guide]
+   (https://github.com/GoogleCloudPlatform/Template/wiki/style.html) for the
+   recommended coding standards for this organization.
+1. Ensure that your code has an appropriate set of unit tests which all pass.
+1. Submit a pull request.
+

LICENSE

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+Custom Lint Rules
+============
+
+The [Android `lint` tool](http://developer.android.com/tools/help/lint.html) is a static code
+ analysis tool that checks your Android project source files for potential bugs and optimization
+ improvements for correctness, security, performance, usability, accessibility, and
+ internationalization. Lint comes with over 100 checks, however it can be extended with additional
+ custom rules.
+
+The Custom Lint Rules API is **not stable** and is subject to change in the future. Be ready to change
+ your custom lint rule implementation when the API changes.
+
+Introduction
+------------
+
+The Android Lint API allows users to create custom lint rules. For example, if you are the author of
+ a library project, and your library project has certain usage requirements, you can write
+ additional lint rules to check that your library is used correctly, and then you can distribute
+ those extra lint rules for users of the library. Similarly, you may have company-local rules you'd
+ like to enforce.
+
+This sample demonstrates how to create a custom lint checks and corresponding tests for those rules.
+
+Getting Started
+---------------
+
+##### Fetch code
+
+`git clone https://github.com/googlesamples/custom-lint-rules.git`
+
+##### Build the validator
+
+`./gradlew build`
+
+##### Copy to the lint directory
+
+`cp ./build/libs/custom-lint-rules.jar ~/.android/lint/`
+
+##### Verify whether the issues are registered with lint
+
+`lint --show MainActivityDetector`
+
+##### Run lint
+
+`lint`
+
+> Note: If you can't run `lint` directly, you may want to include android tools `PATH` in your
+ `~/.bash_profile`.
+> (i.e. `PATH=$PATH:~/Library/Android/sdk/tools`)
+>
+> Then run `source ~/.bash_profile`.
+
+Support
+-------
+
+- Google+ Community: https://plus.google.com/communities/android
+- Stack Overflow: http://stackoverflow.com/questions/tagged/android
+
+If you've found an error in this sample, please file an issue:
+https://github.com/googlesamples/custom-lint-rules/issues
+
+Patches are encouraged, and may be submitted by forking this project and
+submitting a pull request through GitHub.
+
+License
+-------
+Licensed under the Apache 2.0 license. See the LICENSE file for details.
+
+How to make contributions?
+--------------------------
+Please read and follow the steps in the CONTRIBUTING.md

README.md

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+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.
+ */
+
+apply plugin: 'java'
+
+repositories {
+    jcenter()
+    flatDir {
+        dirs 'libs'
+    }
+}
+
+// JDK 1.6 is required to support all versions of Android Studio.
+// See http://tools.android.com/build/studio.
+sourceCompatibility = 1.6
+dependencies {
+    compile 'com.android.tools.lint:lint-api:24.3.0-beta3'
+    compile 'com.android.tools.lint:lint-checks:24.3.0-beta3'
+    testCompile 'junit:junit:4.11'
+    // TODO(nageshs): Ask AS team why this is not in maven
+    testCompile(name: 'testutils-24.3.0-beta3', ext: 'jar')
+    testCompile(name: 'lint-tests', ext: 'jar')
+    testCompile 'com.android.tools.lint:lint:24.3.0-beta3'
+}
+
+jar {
+    manifest {
+        attributes("Lint-Registry": "MyIssueRegistry")
+    }
+}
+
+defaultTasks 'assemble'

build.gradle

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+#Wed Apr 10 15:27:10 PDT 2013
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.2.1-all.zip

gradle/wrapper/gradle-wrapper.jar

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+#!/usr/bin/env bash
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn ( ) {
+    echo "$*"
+}
+
+die ( ) {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+esac
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched.
+if $cygwin ; then
+    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+fi
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >&-
+APP_HOME="`pwd -P`"
+cd "$SAVED" >&-
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
+function splitJvmOpts() {
+    JVM_OPTS=("$@")
+}
+eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
+JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+
+exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"