Compile two apps, but running only one module with Android Studio - android-studio

Question

I have two android projects 'East' & 'ChoosePDF' in Eclipse. 'East' is the main app, the other is a pdf library.
I try to export them from Eclipse to Android Studio.
When I try to run 'East' module, there are two apps installed in device. 'ChoosePDF' is also installed as an app, which should be only complied as a library.
In the 'app managerment' setting, it shows as one app. But in device's desktop, these are two same icons.
This is the project's build.gradle:
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:1.5.0'
}
}
project's settings.gradle is:
include ':ChoosePDF'
include ':East'
Here is module 'East's build.gradle, which is the main project in Eclipse.
apply plugin: 'com.android.application'
dependencies {
compile fileTree(dir: 'libs', include: '*.jar')
compile project(':ChoosePDF')
}
android {
compileSdkVersion 21
buildToolsVersion "23.0.2"
sourceSets {
main {
manifest.srcFile 'AndroidManifest.xml'
java.srcDirs = ['src']
resources.srcDirs = ['src']
aidl.srcDirs = ['src']
renderscript.srcDirs = ['src']
res.srcDirs = ['res']
assets.srcDirs = ['assets']
}
// Move the tests to tests/java, tests/res, etc...
instrumentTest.setRoot('tests')
// Move the build types to build-types/<type>
// For instance, build-types/debug/java, build-types/debug/AndroidManifest.xml, ...
// This moves them out of them default location under src/<type>/... which would
// conflict with src/ being used by the main source set.
// Adding new build types or product flavors should be accompanied
// by a similar customization.
debug.setRoot('build-types/debug')
release.setRoot('build-types/release')
}
}
And this is the dependency library's build.gradle.
apply plugin: 'com.android.library'
dependencies {
compile fileTree(dir: 'libs', include: '*.jar')
}
android {
compileSdkVersion 19
buildToolsVersion "23.0.2"
sourceSets {
main {
manifest.srcFile 'AndroidManifest.xml'
java.srcDirs = ['src']
resources.srcDirs = ['src']
aidl.srcDirs = ['src']
renderscript.srcDirs = ['src']
res.srcDirs = ['res']
assets.srcDirs = ['assets']
}
// Move the tests to tests/java, tests/res, etc...
instrumentTest.setRoot('tests')
// Move the build types to build-types/<type>
// For instance, build-types/debug/java, build-types/debug/AndroidManifest.xml, ...
// This moves them out of them default location under src/<type>/... which would
// conflict with src/ being used by the main source set.
// Adding new build types or product flavors should be accompanied
// by a similar customization.
debug.setRoot('build-types/debug')
release.setRoot('build-types/release')
}
}
I really don't know how it happens. Try to comment out the 'ChoosePDF' in settings.gradle, doesn't work. Try to remove something in 'ChoosePDF's build.gradle, doesn't work.
Really need help to fix it, thanks.