Develop Reference

I can't see the elements by their id in Android Studio

I'm a new Kotlin Programmer. I tried to change the app icon by deleting the ic_launcher.png files and replacing my own images. As i see that is ridiculous what i'm trying to do, i copied the "Main Activity.kt" and "main_activity.xml" files and created a new project. As i tried to copy the files into the new project, the program throws a lot of errors:
It didn't imported the "kotlinx" packet and didn't perceive the elements in the xml file. As i tried to create an another new project to try whether the problem is only for this project, i realized that Android Studio doesn't perceive the xml elements anymore.
Here are some important infos about my project:
The Android Manifest XML File
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ihdovanay.myapplication">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.MyApplication">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
The Build Gradle File of The Project
buildscript {
ext.kotlin_version = "1.4.10"
repositories {
google()
jcenter()
}
dependencies {
classpath "com.android.tools.build:gradle:4.1.0"
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
allprojects {
repositories {
google()
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
The Build Gradle File of the Module
plugins {
id 'com.android.application'
id 'kotlin-android'
}
android {
compileSdkVersion 30
buildToolsVersion "30.0.2"
defaultConfig {
applicationId "com.ihdovanay.myapplication"
minSdkVersion 21
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
implementation 'androidx.core:core-ktx:1.3.2'
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'com.google.android.material:material:1.2.1'
implementation 'androidx.constraintlayout:constraintlayout:2.0.2'
testImplementation 'junit:junit:4.+'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}
I would be very happy if you could solve my problem.

Revised answer after the deprecation of view synthetics.
You're missing the kotlin-android-extensions plugin in your build.gradle. It's responsible for generating synthetic view references.
kotlin-android-extensions is now deprecated, so it is no longer included by default and should no longer be added to projects. You should use findViewById or View Binding.
You can make it work by doing the following, but I don't recommend adding and relying on a deprecated library. Add the line to your plugins block at the top:
plugins {
id 'com.android.application'
id 'kotlin-android'
id 'kotlin-android-extensions'
}

In Android Studio 4.1.1, the following code is missing in build.gradle (module: yourAppName)
id 'kotlin-android-extensions'

Error: "Only the Kotlin standard library is allowed to use the 'kotlin' package"

I want to build my first kotlin project in Android studio 3.0.1 . but i got these 2 errors :
Only the Kotlin standard library is allowed to use the 'kotlin' package .
Error:Execution failed for task ':app:compileDebugKotlin'.
how can i use or add the Kotlin standard library?
manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="kotlin.amirreza.mykotlinproject">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
gradle:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
android {
compileSdkVersion 26
defaultConfig {
applicationId "kotlin.amirreza.mykotlinproject"
minSdkVersion 16
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:26.0.0-beta1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:0.5'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:2.2.2'
}

You set your package name to kotlin.
Change all package kotlin statements in your .kt files to something like package mykotlintest

It's possible to work around this issue by adding the -Xallow-kotlin-package argument when kotlinc is invoked, that's what Kotlin does to build itself. But changing the package name is a cleaner solution.

As error says :
Only the Kotlin standard library is allowed to use the 'kotlin' package
You can not use 'kotlin' for your package name and your Package (applicationId) is :
kotlin.amirreza.mykotlinproject
So you must change it to something else with renaming or creating new applicaton with another package name
like this
com.amirreza.mykotlinproject

As #EmmanuelBourg correctly mentioned, below there is some code to do this
tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
kotlinOptions.freeCompilerArgs += ["-Xallow-kotlin-package"]
}

Android application on Gradle: Unable to merge dex

I have an error with my app in Android studio:
Execution failed for task
':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
> com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex
I use Gradle and Kotlin.
Android Studio 3.0.1.
Windows 10 Pro 64.
I have research this theme on SO and I have tried some solution from here, like that:
Clean and rebuild project. No changes.
Change 'compile' in gradle to 'implementation'. No changes.
Delete .gradle and build directories. No changes.
Add multiDexEnabled true in defaultConfig in gradle. In this case, I have another error:
Execution failed for task ':app:transformClassesWithMultidexlistForDebug'.
> java.io.IOException: Can't write [G:\work\myapp\app\build\intermediates\multi-dex\debug\componentClasses.jar]
(Can't read [C:\Users\Public\.gradle\caches\transforms-1\files-1.1\support-core-utils-27.0.2.aar\e1c9881d763269b67bf59dc03d19c305\jars\classes.jar(;;;;;;**.class)]
(Duplicate zip entry [classes.jar:android/support/v4/content/PermissionChecker$PermissionResult.class]))
My build.gradle:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
android {
compileSdkVersion 27
defaultConfig {
multiDexEnabled true
applicationId "myapp"
minSdkVersion 19
targetSdkVersion 27
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
debug {
applicationIdSuffix ".dev"
}
staging {
debuggable true
applicationIdSuffix ".sta"
}
preproduction {
applicationIdSuffix ".pre"
}
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
repositories {
jcenter()
mavenCentral()
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:27.0.2'
implementation 'com.basecamp:turbolinks:1.0.7'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
// The Client SDK resides on jCenter
implementation 'com.twilio:client-android:1.2.21'
}
My AndroidManifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.tunnll.passenger">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.READ_SMS"/>
<uses-permission android:name="android.permission.RECEIVE_SMS"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name="com.twilio.client.TwilioClientService"
android:exported="false" android:stopWithTask="true"/>
</application>
What am I missing?
UPD
It seems I found out the point after that the problem has appeared. It was after adding Twilio configuration. I used this manual: Twilio and Android
This is all changes that have been done:
Add to build.gradle:
implementation 'com.twilio:client-android:1.2.21'
Add to AndroidManifest:
<service android:name="com.twilio.client.TwilioClientService"
android:exported="false" android:stopWithTask="true"/>
Add to proguard-rules.pro
# Twilio Client
-keep class com.twilio.** { *; }
# Apache HttpClient
-dontwarn org.apache.http.**
That's all. Before this changes I didn't have this error

Use this in your build.gradle in app Module if you want to read an .aar file
for your libs dir:
repositories{
flatDir{
dirs 'libs'
}
}
dependencies {
compile(name:'nameOfYourAARFileWithoutExtension', ext:'aar')
}
But it seems that your problem is multidex(means that you have more than 65K methods in your project so use this:
android {
defaultConfig {
multiDexEnabled true
}
}
and if your minSdk < 20 then use this as well:
compile 'com.android.support:multidex:1.0.1'
Hope it helps!!!

Kotlin RC NoClassDefFoundError

After updating kotlin to RC-1036 i'm facing a weird issue: my code is not even compiled and packed.
When build passes and the app is launched i'm getting ClassNotFoundException: Didn't find class "example.myapplication.MainActivity".
I have tried to decompile apk with apktool and didn't find my classes inside the archive. There are no classes in build/intermediates dir either.
This is my project:
app/build.gradle:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android-extensions'
buildscript {
ext.kotlin_version = '1.0.0-rc-1036'
repositories {
mavenCentral()
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
repositories {
mavenCentral()
}
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"
defaultConfig {
applicationId "example.myapplication"
minSdkVersion 21
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
}
}
sourceSets {
main.java.srcDirs += 'src/main/kotlin'
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest package="example.myapplication"
xmlns:android="http://schemas.android.com/apk/res/android">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
And MainActivity:
package example.myapplication
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
hello.text = "New text"
}
}
Build tools version is 2.0.0-beta2;
Might be something wrong with sourseSets, though nothing works if i try to reconfigure it somehow. Appreciate any help.

You should have both these plugins:
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
The first makes sure the Kotlin code compiles, the second is for the UI imports.

Git submodule causing Failure [INSTALL_FAILED_OLDER_SDK] Android sdk 21

I am working on an app and trying to use the new material design, aka sdk version 21.
I had everything working fine, and then wanted to at a fab (floating action button) using this library.
I added this library as a submodule, using
git submodule add https://github.com/shamanland/floating-action-button
while under C:\Users\USER\AndroidStudioProjects\ProjectName
My file structure looks like so
ProjectName
app
floating-action-button
The issue
Before everything was totally fine, I was able to build and run the project.
But, ever since adding this submodule, when trying to run it, I get the error
Failure [INSTALL_FAILED_OLDER_SDK]
So I'm thinking it has to do with the submodule, but I'm not sure how.
app/build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 21
buildToolsVersion '21.0.2'
defaultConfig {
applicationId "com.mayuonline.ribbit"
minSdkVersion 21
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.android.support:support-v4:21.+'
compile 'com.android.support:cardview-v7:+'
compile 'com.android.support:recyclerview-v7:+'
compile 'com.android.support:palette-v7:+'
}
app/AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="resume.kelseyhrubes">
<uses-sdk tools:node="replace" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
f-a-b/build.gradle
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.android.tools.build:gradle:0.12.2'
classpath 'com.jakewharton.sdkmanager:gradle-plugin:0.12.0'
classpath 'org.robolectric:robolectric-gradle-plugin:0.11.0'
}
}
def isSnapshot() {
return VERSION_NAME.contains('SNAPSHOT')
}
def gradleMvnPush = new File(buildDir, 'gradle-mvn-push.gradle')
if (!gradleMvnPush.exists()) {
buildDir.mkdirs()
ant.get(src: GRADLE_MVN_PUSH, dest: gradleMvnPush)
}
setProperty('GRADLE_MVN_PUSH', gradleMvnPush)
subprojects {
group GROUP
version VERSION_NAME
apply plugin: 'android-sdk-manager'
if (name.startsWith('lib')) {
apply plugin: 'com.android.library'
} else {
apply plugin: 'com.android.application'
}
android {
compileSdkVersion COMPILE_SDK_VERSION as int
buildToolsVersion BUILD_TOOLS_VERSION
defaultConfig {
minSdkVersion MIN_SDK_VERSION as int
targetSdkVersion TARGET_SDK_VERSION as int
versionCode 1
versionName '1.0'
// workaround for https://code.google.com/p/android/issues/detail?id=52962
buildConfigField 'boolean', 'SNAPSHOT', isSnapshot().toString()
}
lintOptions {
abortOnError false
}
}
repositories {
mavenLocal()
mavenCentral()
}
if (isSnapshot()) {
apply plugin: 'robolectric'
dependencies {
// NOTE workaround for sdkmanager plugin
compile 'com.android.support:support-v4:19.0.1'
androidTestCompile 'junit:junit:4.10'
androidTestCompile 'org.robolectric:robolectric:2.3'
androidTestCompile 'com.squareup:fest-android:1.0.8'
}
}
}
f-a-b/AndroidManifest.xml (probably a clue here, I (tried to) bold the areas that Android Studio has turned red
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=" **http://schemas.android.com/apk/res/android** "
package="com.shamanland.fab.example">
<application
android:name=" **.ExampleApplication** "
android:label="#string/app_name"
**android:icon** ="#drawable/ic_launcher"
**android:theme** ="#style/AppTheme"
**android:allowBackup** ="true"
>
<activity android:name=".ExampleListActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=" **.ExampleDetailsActivity** "/>
</application>
</manifest>
I have a strong suspicion that the submodule was added incorrectly.
Really all I want is to use a fab in my app, if anyone can help me figure out what may be wrong, with adding the submodule, or something with my build.gradle, that would really be appreciated!!

This error is usually caused by deploying an APK built with "compileSdkVersion n" to a device or emulator with an API level less than "n". Is your emulator at the right API level?