- Getting Unknown attribute error on all android tag. 
- In layout XML, Auto suggestion is not showing all attributes (like layout_width, layout_height, orientation, orientation & all others android attributes.) 
Here is a Snap shot
 Things i have done to resolve this issue.
Things i have done to resolve this issue.
- Clean Build & Rebuild
- Deleted .idea file
- Invalidated Caches/ Restart.. option
- Turn On Power Save Mode.
SDk is up to date.
In App Level Gridle
apply plugin: 'com.android.application'
android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"
    defaultConfig {
        applicationId "com.example.abhishek.ondemandservice"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'),     'proguard-rules.pro'
        }
    }
}
Application level Gride.
buildscript {
    repositories {
        maven { url "http://dl.bintray.com/populov/maven" }
        jcenter()
        mavenCentral()
    }
    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 {
        maven { url "http://dl.bintray.com/populov/maven" }
        jcenter()
        mavenCentral()
    }
}

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
    