Develop Reference

import android.support.v7.app.AppCompatActivity not found

I have recently migrate one project in androidx .This project working fine . Now when i am opening other project in android studio i am found in all other project i am getting error
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
these all package not found i have not changed any thing other project . Why android support libraries not workig with other project. Please help me how can i run android support lib again this android studio .I have done already invalide chache and restart and also clean project but no luck

You need to use androidX dependencies like this:
import com.google.android.material.navigation.NavigationView;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
Make sure you have updated your app.gradle too
api 'androidx.appcompat:appcompat:1.1.0-rc01'
api 'com.google.android.material:material:1.1.0-alpha08'
You also need to add the following to gradle.properties
android.useAndroidX=true
android.enableJetifier=true
Once you update your gradles and delete the old dependencies Android Studio should find the new ones.

Add the support library to the dependency section.
implementation 'com.android.support:design:28.0.0'

Is the Material Design NavigationView not yet compatible with AndroidX?

I just converted my App from the support library to AndroidX. Everything compiles now and the App starts successfully. However one of my activities uses com.google.android.material.navigation.NavigationView which seems to still depend on the old support library. Specifically I see dependencies on the following classes if I look into the code of NavigationView:
import android.support.annotation.DimenRes;
import android.support.annotation.Dimension;
import android.support.annotation.DrawableRes;
import android.support.annotation.IdRes;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.RestrictTo;
import android.support.annotation.StyleRes;
import com.google.android.material.internal.NavigationMenu;
import com.google.android.material.internal.NavigationMenuPresenter;
import com.google.android.material.internal.ScrimInsetsFrameLayout;
import com.google.android.material.internal.ThemeEnforcement;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.AbsSavedState;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.WindowInsetsCompat;
import android.support.v7.content.res.AppCompatResources;
import android.support.v7.view.SupportMenuInflater;
import android.support.v7.view.menu.MenuBuilder;
import android.support.v7.view.menu.MenuItemImpl;
import android.support.v7.widget.TintTypedArray;
In my apps build gradle I depend on:
implementation "androidx.appcompat:appcompat:1.0.2"
implementation "com.google.android.material:material:1.1.0-alpha01"
Since I am using the new dependency to the material design library (which is the one also given my the AndroidX migration guide), I was expecting all the classes having the correct dependencies. Am I wrong here? Is this not ready yet? Does someone have any additional insights I am missing?

I was also facing the same issue, for me adding following dependency in gradle worked.
implementation 'com.google.android.material:material:1.0.0'
EDIT latest stable version available is:
implementation 'com.google.android.material:material:1.3.0'

Android studio doesnt recognize some libraries.(import statements)

Android studio does not recognize some import statements like
import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManager;
But it recognizes some import statements like
import android.text.TextUtils;
import android.view.KeyEvent;
How can I fix it?

Ensure you have added the necessary dependency in your gradle file and have done a gradle sync to download the required packages
compile 'org.igniterealtime.smack:smack-android:4.1.8'
compile 'org.igniterealtime.smack:smack-tcp:4.1.8'
This worked for me

Android Studio not recognizing Facebook SDK

In build.gradle:
compile 'com.facebook.android:facebook-android-sdk:[4,5)'
In my code:
import com.facebook.AccessToken;
import com.facebook.AccessTokenTracker;
import com.facebook.login.LoginManager;
I don't think this was an issue before, but all of the sudden today it's saying "cannot resolve symbol" for all of the import statements and so lots of things in my code are now wrongly marked as errors, even though when I run my app it works fine. What could be causing this?

tools>android>sync project files with gradle files

Try this:
Ctrl+Shift+Alt+S->selectApp->Dependandies->select"+"->moduledependandies->choose facebooksdk

Cannot resolve symbol 'android' in Import

I am getting error in Android Studio. My import:
imports com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
are not working.

Use
import com.google.android.gms.common.api.GoogleApiClient;
instead of imports to import a class.

Download new version of google-play-services library.
Always update/download newest version of google-play-services library.

you must add
compile 'com.google.android.gms:play-services-location:7.8.0'
in dependencies block, in app/build.gradle.
also update google play in sdk manager