如题，在执行gradle的时候报错：

Checking the license for package Solver for ConstraintLayout 1.0.2 in /usr/local/android-sdk-linux/licenses
Warning: License for package Solver for ConstraintLayout 1.0.2 not accepted.
Checking the license for package ConstraintLayout for Android 1.0.2 in /usr/local/android-sdk-linux/licenses
Warning: License for package ConstraintLayout for Android 1.0.2 not accepted.

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':setting'.
> You have not accepted the license agreements of the following SDK components:
  [ConstraintLayout for Android 1.0.2, Solver for ConstraintLayout 1.0.2].
  Before building your project, you need to accept the license agreements and complete the installation of the missing components using the Android Studio SDK Manager.
  Alternatively, to learn how to transfer the license agreements from one workstation to another, go to http://d.android.com/r/studio-ui/export-licenses.html

build.gradle 编写如下：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.0"

    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
    compile project(path: ':widget')
    compile project(path: ':platform')
    compile project(path: ':account')
}

看提示是说，需要接受证书，并使用android sdk manager 安装缺少的组件。

所以按需要的版本，使用sdkmanager安装并接受许可就好了：

$ANDROID_HOME/tools/bin/sdkmanager "extras;m2repository;com;android;support;constraint;constraint-layout;1.0.2" 
$ANDROID_HOME/tools/bin/sdkmanager "extras;m2repository;com;android;support;constraint;constraint-layout-solver;1.0.2"