Develop Reference

Gradle Error: cannot find symbol variable Settings_main

I currently have a problem changing the layout of my Android app. It doesn't work like usual.
When I want to change the layout to the settings layout with the press of a button, it gives the error: cannot find symbol variable Settings_main.
The code where this happens is
final ImageButton settings = findViewById(R.id.Settings_button);
settings.setOnCLickListener(new View.onClickListener() {
#Override
public void onClick(View v) {
setContentView(R.layout.Settings_main);
}
});
This is the error it's giving me
I have imported
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageButton;
Can someone please help me solve this?
Every name and Id does match according to IntelliJ as well, so I have no idea what could possibly be going wrong.

File-based resource names must contain only lowercase a-z,0-9 or underscore.
Please change file name Settings_main to settings_main

React Native - I want import 2 component with same name

I want to import 2 files from same name when we are importing.
like (It's Possible?):
import en from './en';
import en from './en';

Based on your example, why would you want to import the same component from the same module twice?
If that is indeed what you wanted to do, you could do it as following:
import * as UniqueName1 from "./en"
import * as UniqueName2 from "./en"

setSupportActionBar not working on android 4.4

I'm trying to implement the navigation drawer example using the toolbar. I've referred the documentation link
http://android-developers.blogspot.in/2014/10/appcompat-v21-material-design-for-pre.html
but my app crashes at "setSupportActionBar".
Is there any option to make the toolbar work on previous android versions i.e 4.4,4.3 etc like the google apps i.e gmail, playstore etc
Any help is appreciated.
Thanks.

if it's the case, change
import android.widget.Toolbar;
by
import android.support.v7.widget.Toolbar;

Please see that these are included:
import android.support.v7.widget.Toolbar;
import android.support.v7.app.AppCompatActivity;
class extends AppCompatActivity;
(Also the appcompat.support library should be added in File->Project Structure-> Dependencies.)

Error from import android.R or from layout.main?

I keep either removing import.R or adding mypackage.R or deleting all imports and shift-control O
or deleting R.java.
I still get the error: main.xml cannot be resolved or alternately, R cannot be resolved to a variable. I have cleaned each time. How do you get this to work?
package com.hga;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
public class Hga extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView( R.layout.activity_hga );

Yeah i used to run into those type of problems when i was starting programing for android. The R folder updates itself everytime code is written or saved and when a error occurs in your code for whatver reason it may be the R folder gives you that error report. At first clean but if that doesnt work as it usually wont you want to completely coment out your code /* .... */
then clean and the error should go way now you can pin point which bit of code is causing the error to occur in the R folder.
PS. this was my main source of frustration in coding android apps

How to solve this intent Error ?

I Wrote the Following code :
package com.aamir.cool;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView img = (ImageView)findViewById(R.id.facebook);
img.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.addCategory(Intent.CATEGORY_BROWSABLE);
intent.setData(Uri.parse("http://www.facebook.com/exandrok?ref=tn_tnmn"));
startActivity(intent);
}
});
}
}
I am getting error "Unknown Entity Intent" , "Unknown type of variable intent" .
How to Solve these Error ?

Add the following lines to your import statements:
import android.content.Intent;
import android.net.Uri;

Add the correct import statements
import android.content.Intent
import android.net.Uri;
If you're using Eclipse, you can add/organise/optimise your imports with the following shortcut
Cmd-shift-O on OSX
Ctrl+Shift+O on Windows / Linux
Rawkode Still Getting 2 Error : " Unknown entity 'uri" and "Unknown
member 'main of 'com.aamir.cool.R.id"
Please ensure that main.xml actually exists in your layout folder.

After importing the android.content.Intent; first check your xml files and be sure you dont have any layout problems and delete your R.java file and let it generate that again. after doing that right click to your project Android Projects -> Fix Project Properties then select "Project" and click "Clear" then try to run the code again. if still not working ctrl+a ctrl+x and ssave the file be sure you have no errors and ctrl+v again and try to run again.

Try verifying the AndriodManifest.xml in the main page which generates the package as seen in the gen/com folders