problems with 'com.android.support:appcompat-v7.27.1.1' in the gradle file

Question

This is my dependencies file and there is an underlined red colored text on the compile 'com.android.support:appcompat-v7.27.1.1'

apply plugin: 'com.android.application'
 android {
compileSdkVersion 27
defaultConfig {
    applicationId "com.abc.mcaproject"
    minSdkVersion 21
    targetSdkVersion 27
    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'])


compile 'com.android.support:appcompat-v7.27.1.1'
implementation 'com.android.support.constraint:constraint-layout:1.1.0'
implementation 'com.google.firebase:firebase-database:11.6.0'
implementation 'com.google.firebase:firebase-messaging:11.6.0'
implementation 'com.google.firebase:firebase-auth:11.6.0'
implementation 'com.google.firebase:firebase-storage:11.6.0'
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'
}

apply plugin: 'com.google.gms.google-services'

This because of this I am having problems changing themes in the styles.xml

Answer 1

Reason of fail

You are using incompatible version of firebase with 27.1.1 support version.

Current version > 16.0.0 and you use 11.6.0.

Solution

Update your firebase dependencies versions. I suggest update target sdk version also.

Below is updated gradle as of date 1-10-2018, you can see firebase page to check latest version.

apply plugin: 'com.android.application'
android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.abc.mcaproject"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
    }
    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'
    implementation 'com.android.support.constraint:constraint-layout:1.1.0'
    implementation 'com.google.firebase:firebase-database:16.0.2'
    implementation 'com.google.firebase:firebase-messaging:17.3.2'
    implementation 'com.google.firebase:firebase-auth:16.0.3'
    implementation 'com.google.firebase:firebase-storage:16.0.2'
}

apply plugin: 'com.google.gms.google-services'

Suggestion

Migrate to androidx because Android will not update support libraries after version 28.0.0.