Gradle failed to sync with 'unable to find optional library'

Question

I had to reinstall my system and today I get this error in Android Studio when I try to sync with gradle:

Warning: Unable to find optional library: org.apache.http.legacy

My project gradle is:

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.3.0'
    }
}

allprojects {
    repositories {
        mavenCentral()
    }
}

And my module gradle:

apply plugin: 'android'

android {
    useLibrary  'org.apache.http.legacy'

    compileSdkVersion 23
    buildToolsVersion '23.0.2'
    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 23
    }
    buildTypes {
        release {
        }
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:support-v4:23.1.1'
    compile 'com.android.support:appcompat-v7:23.1.1'
}

From the google docs:

To continue using the Apache HTTP APIs, you must first declare the following compile-time dependency in your build.gradle file:

android {
    useLibrary 'org.apache.http.legacy'
}

I tried the suggestions mention in this thread but they don't work. Same result with android studio 1.5 and 2 preview.

How can I fix this?

Edit: Things I've tried so far:

1. Change gradle classpath versions to 1.3.0, 1.3.1, 1.5.0.

2. Change the compileSdkVersion and targetSdkVersion to 22. Also the buildToolsVersion from 23.0.1, 23.0.0, 22.0.1.

Answer 1

Top level build.gradle - /build.gradle

buildscript {
...
dependencies {
    classpath 'com.android.tools.build:gradle:1.3.1'
}
}

Module specific build.gradle - /app/build.gradle

android {
compileSdkVersion 23
buildToolsVersion "23.0.0"
useLibrary 'org.apache.http.legacy'
...
}

Add org.apache.http.legacy.jar which is in Android/Sdk/platforms/android-23/optional folder to app/libs directory and sync your project

Answer 2

After a lot of working this solutions work for me . ** Studio\Android\sdk\platforms** here delete your android-23 and from sdk manager update api 23 again.** . it will solve your issue.

Answer 3

In my case, it didn't work because I was missing optional.json in <sdk-path>\platforms\android-23\optional\, directory with the following content:

[
  {
    "name": "org.apache.http.legacy",
    "jar": "org.apache.http.legacy.jar",
    "manifest": false
  }
]

Creating a new JSON file with with above content solved the problem for me.

Answer 4

You need to add org.apache.http.legacy.jar jar file in your Android Stuido project's app/libs folder.

  Jar Location - `<SDK LOCATION>\android-sdk\platforms\android-23\optional`  

To do this, just right click on your project and select Show in Explorer then go to ...\app\libs and paste above jar file and Sync your Project with Gradle File

Module:app

android {
compileSdkVersion 'Google Inc.:Google APIs:23'
buildToolsVersion "24.0.0"
defaultConfig {
    applicationId "<ur_app_id>"
    minSdkVersion 15
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}