Develop Reference

After Updating Android studio to 3.1.2 , I get "Failed to load AppCompat ActionBar with unknown error. "

I tried looking other similar questions on stackoverflow, they advice us to changw version of "buildToolsVersion" but I dont see word like that in my gradle file.
My Gradle File (PROJECT):-
buildscript {
repositories {
google()
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.1.2'
// 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
}
My build.gradle (Module:app): This the my second gradle file
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.example.dhruv.testhello"
minSdkVersion 15
targetSdkVersion 28
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 'com.android.support:appcompat-v7:28.0.0-alpha3'
implementation 'com.android.support.constraint:constraint-layout:1.1.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-
core:3.0.2'
}

I had the same problem. I searched so much and I finally found that appcompat-v7:28.0.0-alpha3 has some bug with "Design View" part of Android Studio.
So I suggest to change com.android.support:appcompat-v7:28.0.0-alpha3 to com.android.support:appcompat-v7:28.0.0-alpha1 version and then click File -> Invalidate Caches / Restart. Volla everything is OK.
Of course you should have internet access to download com.android.support:appcompat-v7:28.0.0-alpha1

I was helped by Hossein Seifi's reply but with a change
implementation 'com.android.support:design:28.0.0-alpha3'
to
implementation 'com.android.support:design:28.0.0-alpha1'
and click File -> Invalidate Caches / Restart

Update 2
As you can see in support 28.0.0 release notes.
This will be the last feature release under the android.support
packaging, and developers are encouraged to migrate to AndroidX 1.0.0
Android will not update support libraries from now. So I suggest you migrate to androidx before they deprecated support libraries.
Update
Support 28.0.0 is released, so you can use this stable version.
implementation 'com.android.support:design:28.0.0'
I suggest never use alpha versions, because alpha, beta versions have bugs, that are testing libraries.

module app gradle file looks like this...In your file you are missing buildToolsVersion, adding this may help you
apply plugin: 'com.android.application'
android {
//changes
compileSdkVersion 26
buildToolsVersion "27.0.3"
defaultConfig {
applicationId "com.example.dhruv.testhello"
minSdkVersion 24
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'])
//changes
compile 'com.android.support:appcompat-v7:26.0.2'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-
core:3.0.2'
}

In styles.xml,
Changing the theme from Theme.AppCompat.Light.DarkActionBar to Base.Theme.AppCompat.Light.DarkActionBar has worked for me.

yes its work,
implementation 'com.android.support:design:28.0.0-alpha3'
to
implementation 'com.android.support:design:28.0.0-alpha1'
After that got to File and click -> Invalidate Caches / Restart

At the time of this answer Android Studio 3.1.4 is out with Android Support 28.0.0 Release Candidate(Potential Final, Beta) so please update.
Well, here is a config that will certainly work for you.
targetSdkVersion 28
com.android.support:*:28.0.0-rc01
Where * is the resource type.

Open, res>values>styles.xml, here you will find a line:
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
replace the line with:
<style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
That means: Add the word "Base." starting the name of the parent theme.

Open, res --> values --> styles.xml, here you will find a line like this:
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
change it to:
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
In otherwords, change DarkActionBar to NoActionBar

Toolbar: IllegalStateException - configure your build for VectorDrawableCompat

I'm using Android Studio 2.1.2. I started a new project with minSdkVersion as 19. My activity extends AppCompatActivity. The project starts with an empty activity using a fragment.
When previewing content_main.xml with API 24, all is good. when previewing API 19, I get the following rendering problem:
The following classes could not be instantiated:
- android.support.v7.widget.Toolbar
java.lang.IllegalStateException: This app has been built with an incorrect configuration. Please configure your build for VectorDrawableCompat
I have added every thing I found relevant to the gradle (2 files):
classpath 'com.android.tools.build:gradle:2.1.2'
vectorDrawables.useSupportLibrary = true
buildToolsVersion "24.0.1"
compile 'com.android.support:appcompat-v7:24.1.1'
compile "com.android.support:support-v4:24.1.1"
compile 'com.android.support:design:24.1.1
But still the error appears. I've found a lot of answers on internet. But none helped. Is there a problem using the new toolbar with API 19?

This worked well for me
android {
compileSdkVersion 23
buildToolsVersion "23.0.1"
defaultConfig {
applicationId "com.example.app"
minSdkVersion 15
targetSdkVersion 23
versionCode 1
versionName "1.0"
generatedDensities = []
}
// This is handled for you by the 2.0+ Gradle Plugin
aaptOptions {
additionalParameters "--no-version-vectors"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
Notice this in the above code:
// This is handled for you by the 2.0+ Gradle Plugin
aaptOptions {
additionalParameters "--no-version-vectors"
}
and
generatedDensities = []

from this google Issue
buildscript {
...
dependencies {
classpath 'com.android.tools.build:gradle:2.1.0'
}
}
check this issue for more help.
UPDATE
configured your app build.gradle file as follows
android {
defaultConfig {
vectorDrawables.useSupportLibrary = true
}
}
dependencies {
compile 'com.android.support:appcompat-v7:23.3.0'
}
Source
Age Of Vectors

Firstly, there are two types of gradle files.
build.gradle(Project: ProjectName)
build.gradle(Module: app)
For more information on these two files, go through this answer.
Coming to your question,
I've found a lot of answers on the net but none helped. I'm using
Android Studio 2.1.2, my activity extends AppCompatActivity and added
to the gradle (2 files) every thing I found relevant: but still the
error appears.
From whatever you have posted, it seems like you didn't add right things at right places.
You shouldn't place your application dependencies in build.gradle(Project: ProjectName) - Android Studio says,
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
Hence, replace your dependencies in build.gradle(Project: ProjectName) with below
dependencies {
classpath 'com.android.tools.build:gradle:2.1.2'
}
Replace your dependencies in build.gradle(Module: app) with below
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:24.1.1'
compile 'com.android.support:design:24.1.1'
}
After doing as mentioned above, you will see a "Sync Now" option on the Top Right. Click it. Android Studio will take care of remaining things.
Also this question similar is to yours. Go through it. It may help.

Add :
build.gradle
defaultConfig {
...
vectorDrawables.useSupportLibrary = true
...
}
And on top of your Activity class:
static {
AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
}
And one last thing put your vector drawables inside any other drawables like selector, LayerList, etc. Something like below:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/drawable_vector" />
</selector>
And use this above drawable everywhere instead of setting vector drawables directly. This will at other places as well whenever you want to use vector drawables on pre-lollipop devices.

How to implement Robobinding in android app

I'm trying to implement the MVVM architecture using Robobinding. Here's the link I'm following for the Environment setup of Robobinding in Android Studio(without AspectJ):
http://robobinding.github.io/RoboBinding/getting_started.html#_android_studio
This is what my app level Build.gradle looks like after adding the dependencies:
apply plugin: 'com.android.application'
apply plugin: 'com.neenbedankt.android-apt'
android {
compileSdkVersion 23
buildToolsVersion "23.0.1"
defaultConfig {
applicationId "com.example.simpletimerapp"
minSdkVersion 14
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile "org.robobinding:robobinding:${robobindingVersion}"
}
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.neenbedankt.gradle.plugins:android-apt:1.+'
}
}
The problem is gradle build fails with the following error:
Error:(26, 0) Could not find property 'robobindingVersion' on org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler_Decorated#2ccd2d42.
Open File
EDIT 1:
On replacing ${robobindingVersion} in the dependencies block with 0.8.12 (latest version of robobinding), gradle build finishes successfully. But now, I'm unable to use the "bind" attribute in the views in my layout files. This is the error:
Unexpected namespace prefix "bind" found for tag TextView
EDIT 2:
Still can't find the solution. So, I downloaded this minimal android app (from their official github page) which implements robobinding and edited it to create my own app. It's working fine now.

Android build fails for task: ':app:transformClassesWithDexForDebug'

I just started a project with my Android Studio. I suddenly started to have problems with layout preview. Preview renders the screen normally but I get an annoying Rendering Problems window that says:
Rendering Problems The following classes could not be found:
- android.support.v7.internal.app.WindowDecorActionBar (Fix Build Path, Create Class)
Tip: Try to build the project.
Of course, I tried many things.
build the project
clean and rebuild the project
clean, rebuild, sync and then rebuild again
cleaning app data before doing any of the above
uninstalled and reinstalled the android studio and then repeated the above steps.
Any idea what the problem might be?
My build.gradle is:
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.0.0-alpha1'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
apply plugin: 'com.android.application'
android {
signingConfigs {
}
compileSdkVersion 23
buildToolsVersion "23.0.1"
defaultConfig {
applicationId "gr.asd.asdapp"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
dexOptions {
jumboMode = true
}
}
dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
testCompile 'junit:junit:4.12'
compile 'com.android.support:support-v4:23.1.1'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:design:23.1.1'
}

As suggested here
Rendering Problems The following classes could not be found: android.support.v7.internal.app.WindowDecorActionBar
Change your theme to inherit from a Base Theme.
<style name="AppTheme" parent="Theme.AppCompat.Mpla.Mpla">
<!-- Customize your theme here. -->
</style>
with
<style name="AppTheme" parent="Base.Theme.AppCompat.Mpla.Mpla">
<!-- Customize your theme here. -->
</style>
Android Studio has a terrible out-of-the-box experience. But it used to be worse. A completely new project that was not using the latest API would yield Obsolete class errors and you had to replace Activity with AppCompatActivity to make it work
Having said that, if you target the latest API your problem will be gone but obviously that's not a solution :)

android.support.v7.internal.app.WindowsDecorActionBar Rendering Problems

Hello developers friends!
I am studying development for Android in recent months.
But just this last week came the question . How can I solve the problem of the image below ?

ActionBar is deprecated in the latest android api... If you need to use it make sure your theme read as follow:
<style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
you can find this in:
res > values > styles.xml

I was also getting these errors.
Solved by setting similar versions to the fields in gradle file as below
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.0"
defaultConfig {
applicationId "com.intplus.hijackid"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.0.0'
}
Observe the versions compileSdkVersion, buildToolsVersion, targetSdkVersion also the support v7 version.
I was having appcompat-v7:21.0.3. Changes as shown above fixed the issues!