"Hello world" Android app with as few files as possible, no IDE, and text editor only

Creating an "Hello World" Android app using only a text editor and command-line tools requires a few steps. Here's how you can do it:

1. Install Java Development Kit (JDK):
   Download and install the JDK from the Oracle website: https://www.oracle.com/java/technologies/javase-downloads.html

2. Install Android SDK:
   Download the Android SDK Command-line tools from the official Android website: https://developer.android.com/studio

   Extract the downloaded ZIP file to a location on your computer.

3. Set Environment Variables:
   Add the following environment variables to your system (replace with actual paths):

   makefileCopy code
   ANDROID_SDK_ROOT=C:\path\to\android-sdk
   
   JAVA_HOME=C:\path\to\jdk
   
   PATH=...;%ANDROID_SDK_ROOT%\tools\bin;%ANDROID_SDK_ROOT%\platform-tools;%JAVA_HOME%\bin
   
   

4. Create Project:
   Open a text editor and create a new directory for your project. Inside that directory, create the following directories:

   cssCopy code
   myapp/
   
   ├── src/
   
   │   └── main/
   
   │       └── java/
   
   │           └── com/
   
   │               └── myapp/
   
   └── res/
   
       └── values/
   
           └── strings.xml
   
   

5. Write Code:
   In myapp/src/main/java/com/myapp/, create a file named MainActivity.java with the following code:

   javaCopy code
   package com.myapp;
   
   
   
   import android.app.Activity;
   
   import android.os.Bundle;
   
   import android.widget.TextView;
   
   
   
   public class MainActivity extends Activity {
   
       @Override
   
       protected void onCreate(Bundle savedInstanceState) {
   
           super.onCreate(savedInstanceState);
   
           setContentView(R.layout.activity_main);
   
           TextView textView = findViewById(R.id.textView);
   
           textView.setText("Hello, World!");
   
       }
   
   }
   
   

6. Write XML Layout:
   In myapp/res/layout/, create a file named activity_main.xml with the following code:

   xmlCopy code
   <?xml version="1.0" encoding="utf-8"?>
   
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   
       android:layout_width="match_parent"
   
       android:layout_height="match_parent"
   
       android:orientation="vertical">
   
       <TextView
   
           android:id="@+id/textView"
   
           android:layout_width="wrap_content"
   
           android:layout_height="wrap_content"
   
           android:text="TextView" />
   
   </LinearLayout>
   
   

7. Compile and Build:
   Open a command prompt and navigate to the myapp directory.

   Run the following commands:

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   %ANDROID_SDK_ROOT%\platform-tools\adb kill-server
   
   %ANDROID_SDK_ROOT%\platform-tools\adb start-server
   
   %ANDROID_SDK_ROOT%\platform-tools\adb devices
   
   

   You should see your connected Android device or emulator.

   Build the APK:

   perlCopy code
   %ANDROID_SDK_ROOT%\platform-tools\adb compile
   
   

   Install and run the app:

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   %ANDROID_SDK_ROOT%\platform-tools\adb install bin\classes-debug.apk
   
   

   The app should install and run on your connected Android device or emulator.

That's it! You've created a basic "Hello World" Android app using a text editor and command-line tools. Remember that this is a simplified example, and in real-world scenarios, you would need to handle more complex tasks such as managing dependencies, version control, and creating a more structured project setup.