错误：任务'：app：dexDebug'的执行失败

我试图在Mac版Android Studio的模拟器中添加Google Maps服务。我用它在模拟器中添加了Google Play服务，现在出现此错误。

我还在“库”中添加了Google play jar

建立错误

Error:Execution failed for task ':app:dexDebug'.
> com.android.ide.common.internal.LoggedErrorException: Failed to run command:
            /Applications/Android Studio.app/sdk/build-tools/21.0.0/dx --dex --num-threads=4 --output /Users/BrijD/Desktop/Final_maps/app/build/intermediates/dex/debug /Users/BrijD/Desktop/Final_maps/app/build/intermediates/classes/debug /Users/BrijD/Desktop/Final_maps/app/build/intermediates/dependency-cache/debug /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/classes-0fd5fdfe526893278be8c195ce134eaf1d9f1e86.jar /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/classes-1c1ab6ce82c35aba8a1d88f2624cf1338444a247.jar /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/classes-3fa4a9ac8fa2216bad3a7f16c9a774b0dc355d43.jar /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/classes-8f6dc1447c1249308d36a8f93d1adf33837f8664.jar /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/internal_impl-21.0.0-fd4beb3682904051af27f723f6ba9423e4f00b8a.jar /Users/BrijD/Desktop/Final_maps/app/build/intermediates/pre-dexed/debug/support-annotations-21.0.0-ee576f91b45a6538d4156fc6e674b6f65034f74e.jar
          Error Code:
            2
          Output:
            UNEXPECTED TOP-LEVEL EXCEPTION:
            com.android.dex.DexException: Multiple dex files define Lcom/google/android/gms/actions/ReserveIntents;
                at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
                at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
                at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
                at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
                at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
                at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:454)
                at com.android.dx.command.dexer.Main.runMonoDex(Main.java:302)
                at com.android.dx.command.dexer.Main.run(Main.java:245)
                at com.android.dx.command.dexer.Main.main(Main.java:214)
                at com.android.dx.command.Main.main(Main.java:106)

AndroidMainefest.xml

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="dormroomdevelopers.final_maps" >

        <uses-permission android:name="android.permission.INTERNET"/>
        <application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >
            <activity
                android:name=".MyActivity"
                android:label="@string/app_name" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />

                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
            <activity android:name=".MapsActivity">
                <meta-data
                    android:name="com.google.android.maps.v2.API_KEY"
                    android:value="*****************************"/>
            </activity>
            <meta-data android:name="com.google.android.gms.version"
                android:value="@integer/google_play_services_version" />
        </application>

    </manifest>

应用程序build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 21
    buildToolsVersion "21"

    defaultConfig {
        applicationId "dormroomdevelopers.final_maps"
        minSdkVersion 18
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.google.android.gms:play-services:6.5.87'
    compile 'com.google.android.gms:play-services-maps:6.5.+'
}

proguard-rules.pro

-keep class * extends java.util.ListResourceBundle {
    protected Object[][] getContents();
}

-keep public class com.google.android.gms.common.internal.safeparcel.SafeParcelable {
    public static final *** NULL;
}

-keepnames @com.google.android.gms.common.annotation.KeepName class *
-keepclassmembernames class * {
    @com.google.android.gms.common.annotation.KeepName *;
}

-keepnames class * implements android.os.Parcelable {
    public static final ** CREATOR;
}