Android java: input events processing (collection)

There 2 ways to handle input events from user input

1. Immediate: using listener
2. At process: at the end to process data, usually user fire "process" button 

TimePicker

1. Immediate 

...
        //on view created
        // date picker
        TimePicker myTimePicker = view.findViewById(R.id.my_time_picker);
        myTimePicker.setOnTimeChangedListener(timeChangeListener);
...
    // TimePicker Listeneer
    private final TimePicker.OnTimeChangedListener timeChangeListener =
            new TimePicker.OnTimeChangedListener() {
        @Override
        public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {
            // TODO
        }
    };

2.  At process

    // Pull the values exactly as they are right now
    int hour = timePicker.getHour();
    int minute = timePicker.getMinute();

RadioGroup

1. Immediate

...
        //on view created
        // date picker
        RadioGroup radioSelectModeBackup = view.findViewById(R.id.radio_select_mode_backup);
        radioSelectModeBackup.setOnCheckedChangeListener(radioListener);
...
    // RadioGroup Listener
    RadioGroup.OnCheckedChangeListener radioListener = new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(@NonNull RadioGroup radioGroup, int idSelected) {
            if (idSelected==R.id.radio_weekly) {
                // weekly
            } else if (idSelected==R.id.radio_moonthly) {
                // monthly
            }
        }
    };

2. At process 

    // Inside your "Save" or "Submit" button click listener
    int selectedId = radioSelectModeBackup.getCheckedRadioButtonId();

    if (selectedId == R.id.radio_weekly) {
        // Logic for weekly backup
    } else if (selectedId == R.id.radio_moonthly) {
        // Logic for monthly backup
    } else {
        // Nothing is selected (returns -1 if no default is set in XML)
    }

 

 

 

 

Debian 13: using systemd timesync to update ntp client time

Since Debain Jessie, Debian use systemd to synchronize ntp clinet

To list timezone:

# timedatectl list-timezones | grep Jakarta
Asia/Jakarta

To set timezone:

# timedatectl set-timezone Asia/Jakarta

To show

# timedatectl 
               Local time: Mon 2026-01-12 12:44:27 WIB
           Universal time: Mon 2026-01-12 05:44:27 UTC
                 RTC time: Mon 2026-01-12 05:44:27
                Time zone: Asia/Jakarta (WIB, +0700)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Edit /etc/systemd/timesyncd.conf

...
[Time]
#NTP=
NTP=0.id.pool.ntp.org 1.id.pool.ntp.org 2.id.pool.ntp.org 2.id.pool.ntp.org 3.id.pool.ntp.org
#FallbackNTP=0.debian.pool.ntp.org 1.debian.pool.ntp.org 2.debian.pool.ntp.org 3.debian.pool.ntp.org
...

To restart service

# systemctl restart systemd-timesyncd

you can use old way using ntp client, but you need to remove this package

# timedatectl set-ntp false

Now you can install ntp and edit configuration /etc/ntp.conf.

 

 

Java: using build tool gradle wrapper to setup project and run

 

• java application openjdk 17
• gradle 8.7

install gradle 

# apt-get install gradle 


create folder project example

$ mkdir example
$ cd example

create init project

wrap gradle version for your project 

$ gradle wrapper --gradle-version 8.7
openjdk version "17.0.16" 2025-07-15
OpenJDK Runtime Environment (build 17.0.16+8-Debian-1deb12u1)
OpenJDK 64-Bit Server VM (build 17.0.16+8-Debian-1deb12u1, mixed mode, sharing)

init using gradle 8.7  debian 13 uses old 4.4 

$ ./gradlew init \
  --type java-application \
  --dsl groovy \
  --test-framework junit-jupiter \
  --package com.dedetok \
  --project-name example
openjdk version "17.0.16" 2025-07-15
OpenJDK Runtime Environment (build 17.0.16+8-Debian-1deb12u1)
OpenJDK 64-Bit Server VM (build 17.0.16+8-Debian-1deb12u1, mixed mode, sharing)
Downloading https://services.gradle.org/distributions/gradle-8.7-bin.zip
...............................................................................................................................
Unzipping ~/.gradle/wrapper/dists/gradle-8.7-bin/bhs2wmbdwecv87pi65oeuq5iu/gradle-8.7-bin.zip to ~/.gradle/wrapper/dists/gradle-8.7-bin/bhs2wmbdwecv87pi65oeuq5iu
Set executable permissions for: ~/.gradle/wrapper/dists/gradle-8.7-bin/bhs2wmbdwecv87pi65oeuq5iu/gradle-8.7/bin/gradle

Welcome to Gradle 8.7!

Here are the highlights of this release:
 - Compiling and testing with Java 22
 - Cacheable Groovy script compilation
 - New methods in lazy collection properties

For more details see https://docs.gradle.org/8.7/release-notes.html

Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details

Enter target Java version (min: 7, default: 21): 17

Select application structure:
  1: Single application project
  2: Application and library project
Enter selection (default: Single application project) [1..2] 1

Generate build using new APIs and behavior (some features may change in the next minor release)? (default: no) [yes, no] no


> Task :init
To learn more about Gradle by exploring our Samples at https://docs.gradle.org/8.7/samples/sample_building_java_applications_multi_project.html

BUILD SUCCESSFUL in 5m 12s
1 actionable task: 1 executed

./settings.gradle

plugins {
    // Apply the foojay-resolver plugin to allow automatic download of JDKs
    id 'org.gradle.toolchains.foojay-resolver-convention' version '0.8.0'
}

rootProject.name = 'example'
include('app')

./app/build.gradle

plugins {
    // Apply the application plugin to add support for building a CLI application in Java.
    id 'application'
}

repositories {
    // Use Maven Central for resolving dependencies.
    mavenCentral()
}

dependencies {
    // Use JUnit Jupiter for testing.
    testImplementation libs.junit.jupiter

    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'

    // This dependency is used by the application.
    implementation libs.guava
}

// Apply a specific Java toolchain to ease working on different environments.
java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(17)
    }
}

application {
    // Define the main class for the application.
    mainClass = 'com.dedetok.App'
}

tasks.named('test') {
    // Use JUnit Platform for unit tests.
    useJUnitPlatform()
}

./gradle/libs.versions.toml

[versions]
guava = "32.1.3-jre"
junit-jupiter = "5.10.1"

[libraries]
guava = { module = "com.google.guava:guava", version.ref = "guava" }
junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }

To show current gradle version

$ ./gradlew --version

------------------------------------------------------------
Gradle 8.7
------------------------------------------------------------

Build time:   2024-03-22 15:52:46 UTC
Revision:     650af14d7653aa949fce5e886e685efc9cf97c10

Kotlin:       1.9.22
Groovy:       3.0.17
Ant:          Apache Ant(TM) version 1.10.13 compiled on January 4 2023
JVM:          17.0.16 (Debian 17.0.16+8-Debian-1deb12u1)
OS:           Linux 6.12.57+deb13-amd64 amd64

Test run

$ ./gradlew run
Path for java installation '/usr/lib/jvm/openjdk-17' (Common Linux Locations) does not contain a java executable

> Task :app:run
Hello World!

BUILD SUCCESSFUL in 473ms
2 actionable tasks: 1 executed, 1 up-to-date

or you can run using style $ ./gradlew :app:run

Now add maridb jcoonect into project, using Traditional Groovy Approach. edit ./app/build.gradle

...
dependencies {
    // Use JUnit Jupiter for testing.
    testImplementation libs.junit.jupiter

    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'

    // This dependency is used by the application.
    implementation libs.guava

    // mariadb jconnector (single file no need change libs.versions.toml
    implementation 'org.mariadb.jdbc:mariadb-java-client:3.3.3'

    // using libs.versions.toml must editing this file 
    //implementation libs.mariadb.client

}
...

If you wish to useing Version Catalog Approach, use 2nd option for ./app/build.gradle and edit libs.version.toml

[versions]
guava = "32.1.3-jre"
junit-jupiter = "5.10.1"
mariadb = "3.3.3"

[libraries]
guava = { module = "com.google.guava:guava", version.ref = "guava" }
junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }
mariadb-client = { group = "org.mariadb.jdbc", name = "mariadb-java-client", version.ref = "mariadb" }


use Version Catalog Approach for complex project and involving multiple developers.

Edit ./app/src/main/java/com/dedetok/App.java

/*
 * This source file was generated by the Gradle 'init' task
 */
package com.dedetok;

import java.sql.*;

public class App {
    public String getGreeting() {
        return "Hello World!";
    }

    public static void main(String[] args) throws SQLException {
        System.out.println(new App().getGreeting());
        
        String dbUrl = "jdbc:mariadb://localhost:3306/mydatabase";
        String dbUName = "myuname";
        String dbPass = "mypass";
        
        Connection conn = DriverManager.getConnection(dbUrl, dbUName, dbPass);

    }
}

To generate single file jar for your project, edit  ./app/build.gradle

...
jar {
    duplicatesStrategy = DuplicatesStrategy.EXCLUDE

    // change with yours
    manifest {
        attributes "Main-Class": "com.dedetok.App"
    }

    from {
        configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
    }
}
...

You can run directly using java command

$ ./gradlew build
...
$ java -jar ./app/build/libs/app.jar
Hello World!

Your jar file location is ./app/build/libs/

Now you can edit  ./app/src/main/java/com/dedetok/App.java finish your project. Use any text editor if you wish.

Debian 13: bash to clean up unused gradle in folder $HOME/.gradle

stop any gradle daemon (better run this after you start your Debian)

copy paste this bash and change permission to execute

#!/bin/bash

# Set the cutoff date yyyy-mm-dd
CUTOFF_DATE="2025-08-01"

# Gradle folder
GRADLE_DIR="$HOME/.gradle"

# List of folders to clean
FOLDERS=("android" "build-scan-data" "caches" "daemon" "kotilin-profile" "native" "notifications" "undefined-build" "wrapper" ".tmp")

# 1. Stop Gradle Daemons first so files aren't locked
if [ -f "$GRADLE_DIR/daemon" ]; then
    echo "Stopping Gradle daemons..."
    gradle --stop 2>/dev/null || ./gradlew --stop 2>/dev/null
fi

echo "Cleaning Gradle folders in $GRADLE_DIR modified before $CUTOFF_DATE..."

for folder in "${FOLDERS[@]}"; do
    TARGET="$GRADLE_DIR/$folder"
    if [ -d "$TARGET" ]; then
        echo "Processing $TARGET..."
        # Find and delete files modified before the cutoff date
        find "$TARGET" -type f ! -newermt "$CUTOFF_DATE" -print -delete
        # Remove empty directories
        find "$TARGET" -type d -empty -print -delete
    else
        echo "Folder $TARGET does not exist, skipping."
    fi
done

echo "Cleanup complete."

Note:

• change CUTOFF_DATE for any desire date
• add or remove FOLDERS depends on your folder structure 

termux android: split video using ffmpeg into smaller size

Requirement:

Install termux from 

• play store 
• github.com/termux/termux-app latest but require allow install from unknown source

open termux and update

$ pkg upgrade

install ffmpeg

$ pkg install ffmpeg

Allow termux to manage files

$ termux-setup-storage

 Target

• every piece has 1 minutes 58 seconds
• resolution low 480
• output h264
• sound mono

command to convert '172967815750944 (1).mp4'

$ ffmpeg -i 172967815750944\ \(1\).mp4 -vf scale=-2:480 -r 25 -c:v libx264 -preset veryfast -crf 28 -ac 1 -c:a aac -b:a 96k -f segment -segment_time 118 -reset_timestamps 1 out_%03d.mp4

this command will create files with name startwing with out_[number].mp4

You can see the files from other applications e.g. photos, files, etc. move it to Movies or Download folder

$ mv out_*.mp4 /storage/emulated/0/Movies/


This is fastest way to split video into smaller size, but you need to write the long command..