Tom Ordonez

Data Science, Machine Learning, Software Engineering

Troubleshooting Building an Android App


Using Android Studio 3.5, I had to load a project that was built in another version.

ERROR: failed to find target with hash string 'android-22'

When building the app it got stuck on this error:

ERROR: failed to find target with hash string 'android-22' in: /home/tom/Android/Sdk
Install missing platform(s) and sync project

I clicked on Install missing platform(s)

Packages to install: 
- Android SDK Platform 22 (platforms;android-22)

Preparing "Install Android SDK Platform 22 (revision: 2)".
Downloading https://dl.google.com/android/repository/android-22_r02.zip
"Install Android SDK Platform 22 (revision: 2)" ready.
Installing Android SDK Platform 22 in /home/tom/Android/Sdk/platforms/android-22
"Install Android SDK Platform 22 (revision: 2)" complete.
"Install Android SDK Platform 22 (revision: 2)" finished.

ERROR: failed to find Build Tools revision 23.0.2

Then I got this error

ERROR: failed to find Build Tools revision 23.0.2
Install Build Tools 23.0.2 and sync project
Upgrade plugin to version 3.5.0 and sync project

I clicked on Install Build Tools 23.0.2

Packages to install: 
- Android SDK Build-Tools 23.0.2 (build-tools;23.0.2)

Preparing "Install Android SDK Build-Tools 23.0.2 (revision: 23.0.2)".
Downloading https://dl.google.com/android/repository/build-tools_r23.0.2-linux.zip
"Install Android SDK Build-Tools 23.0.2 (revision: 23.0.2)" ready.
Installing Android SDK Build-Tools 23.0.2 in /home/tom/Android/Sdk/build-tools/23.0.2
"Install Android SDK Build-Tools 23.0.2 (revision: 23.0.2)" complete.
"Install Android SDK Build-Tools 23.0.2 (revision: 23.0.2)" finished.

ERROR: Failed to resolve: com.android.support:appcompat-v7:22.2.1

Then I got these errors

ERROR: Failed to resolve: com.android.support:appcompat-v7:22.2.1
Add Google Maven repository and sync project
Show in Project Structure dialog
Affected Modules: app


ERROR: Failed to resolve: com.android.support:design:22.2.1
Add Google Maven repository and sync project
Show in Project Structure dialog
Affected Modules: app

I clicked on Add Google Maven repository and sync project.

This opened a tab Refactoring preview and pointed to a file build.gradle.

Here are two great resources:

As explained in the above resources, there are many repositories when building an Android app:

  • jcenter()
  • google()
  • The Android repository installed by the SDK Manager
  • Other repositories

jcenter() is used for open source libraries, like the Android plugin for gradle. google() is used for support libraries. More about this one at Google's Maven Repository. There are gradle libraries listed inside com.android.tools.build.

One of the resources also said that for Android Studio 3.0 and higher, google() should already be added.

Comparing with an app that compiled correctly

I read somewhere on StackOverflow that a good way for troubleshooting was looking at the differences between an app that compiled correctly with the one that didn't.

I checked a project I previously created and compiled correctly.

This is what build.gradle looked like:

build.gradle(Project: Test App)

// Top-level build file where you can add
configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        google()
        jcenter()     
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
allprojects {
    repositories {
        google()
        jcenter()
    }
}
task clean(type: Delete) {
    delete rootProject.buildDir
}

Back to the project that was not compiling correctly. I opened the build.gradle file:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.5.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

I can clearly see that two things are different:

  • google() is missing.
  • Replaced this classpath 'com.android.tools.build:gradle:1.5.0' with 3.5.0.

I added google() to both buildscript and allprojects. Then towards the top right on the blue warning Try Again.

ERROR: Could not find method google() for arguments [] on repository container

Then I got this error:

ERROR: Could not find method google() for arguments [] on repository container.

Here is another resource:

It has these instructions:

  • Go to the Android Project tab
  • Gradle Scripts
  • Open the file gradle-wrapper.properties

It had the following:

distributionUrl=https\://services.gradle.org/distributions/gradle-2.8-all.zip

Comparing the Android app that built correctly. The same file had this:

distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip

Saved the file and clicked on Try Again

Now it built the App without errors.

Gradle Sync Issues

There are still a few warnings after compiling the app.

  • Configuration 'compile' is obsolete and has been replaced with 'implementation' and 'api'
  • Configuration 'testCompile' is obsolete and has been replaced with 'testImplementation'
  • The specified Android SDK Build Tools version (23.0.2) is ignored, as it is below the minimum supported version (28.0.3) for Android Gradle Plugin 3.5.0

Reviewing the build.gradle(Module: app) files for the app that compiled correctly with the one that didn't.

The App that compiled correctly shows this:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.2"
    defaultConfig {
        applicationId "com.example.myapplicationforexample"
        minSdkVersion 23
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
}

Compared to the App that didn't compile

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "mooc.vandy.java4android.shapes"
        minSdkVersion 22
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    testOptions {
        unitTests.returnDefaultValues = true
        unitTests.all{
            ignoreFailures = true
            maxHeapSize = "1024m"
        }
    }
    packagingOptions {
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:22.2.1'
    compile 'com.android.support:design:22.2.1'

    compile ("org.apache.commons:commons-lang3:3.3.2")
    compile ("com.google.guava:guava:17.0")
}

A few things are different.

App that compiled:

compileSdkVersion 29
buildToolsVersion "29.0.2"
minSdkVersion 23
targetSdkVersion 29
implementation fileTree(dir: 'libs', include: ['*.jar'])
testImplementation 'junit:junit:4.12'

App that didn't compile:

compileSdkVersion 22
buildToolsVersion "23.0.2"
minSdkVersion 22
targetSdkVersion 22
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:22.2.1'
compile 'com.android.support:design:22.2.1'
// compile is deprecated use implementation

I made the changes and compiled again.

Configuration 'compile' is obsolete

Only one issue remains:

  • Configuration 'compile' is obsolete and has been replaced with 'implementation' and 'api'

For this section. I replaced compile with implementation and testCompile with testImplementation.

dependencies {
        compile fileTree(dir: 'libs', include: ['*.jar'])
        testCompile 'junit:junit:4.12'
        compile 'com.android.support:appcompat-v7:22.2.1'
        compile 'com.android.support:design:22.2.1'

        compile ("org.apache.commons:commons-lang3:3.3.2")
        compile ("com.google.guava:guava:17.0")
    }

GradleCompatible error in build.gradle(Module: app)

After making this change, yet another error showed up, underlined red on these two lines:

compile 'com.android.support:appcompat-v7:22.2.1'
compile 'com.android.support:design:22.2.1'

The error says:

Issue id: GradleCompatible
Version 28 (intended for Android Pie and below) is the last version of the legacy support library, so we recommend that you migrate to AndroidX libraries when using Android Q and moving forward. The IDE can help with this: Refactor > Migrate to AndroidX.
Inspection info: There are some combinations of libraries, or tools and libraries, that are incompatible, or can lead to bugs. One such incompatibility is compiling with a version of the Android support libraries that is not the latest version (or in particular, a version lower that your targetSdkVersion)

As seen here it says that AndroidX is a major improvement to the original Android Support Library, which is no longer maintained.

And this one about migrating to AndroidX, which basically follows the same warning above to use Refactor > Migrate to AndroidX.

The Refactoring Preview shows References to be changed:

Usage in import in MainActivity.java

import android.support.v7.app.AppCompatActivity;

Usage in Gradle build script in build.gradle(Module:app)

implementation 'com.android.support:appcompat-v7:22.2.1'
implementation 'com.android.support:design:22.2.1'

Clicked on Do Refactor.

It made these changes:

In MainActivity.java:

import androidx.appcompat.app.AppCompatActivity;

In build.gradle(Module:app):

implementation 'androidx.appcompat:appcompat:1.0.0'
implementation 'com.google.android.material:material:1.0.0'

No more errors.