Android Hub 4 you : the free android programming tutorial (2024)

Monday, July 29, 2019

Kotlin Introduction and Examples | Kotlin Hello Example | Kotlin For Loop | Kotlin While Loop | Kotlin Array | Android Kotlin

Dear Friends, Now in thesedays ‘Kotlin’ have been theverypopularprogramming language forsoftware developmentspecially forAndroidDevelopment soletus have a quick look and then in nextBlog/Post we willuseit inAndroidProjects.

Question:Whatis'Kotlin'?
Answer:'Kotlin'isa cross-platform statically typed language developed byJetBrains.

Question:Whatarethe variable types in 'Kotlin'?
Answer:Belowarethemainvariable types in 'Kotlin'-
Characters:'Kotlin'uses‘Char’ keywordfor Characters.

Booleans:'Kotlin' uses ‘booleans’keywordtorepresentBooleans whichhave2 values true or false.

Number:'Kotlin' have almost same keywords as Java for Numbertype-Double, Float, Long, Int, Short, Byte.

Strings:In 'Kotlin' Strings arerepresentedby the 'String' keyword.

Arrays:In 'Kotlin' Arrays arerepresentedby theArray class, that hasgetandsetfunctions.We willseesomeexamplesinlaterpost.

Question:How touse/writevariablesin 'Kotlin'?
Answer:Basically, there are two types of use of variables in 'Kotlin' language –
i)Read only or final variable(definewith 'val'keyword)-
valnum1:Int= 110//Intwithassignment
valnum3:Int//withoutassignment
valname:String = “Manish”//String typewithassignment

ii)Reassigned variables(definewith 'var'keyword)-
varnum1:Int = 110//withassignment
num1=num1+90 //wechangethevalueofReassigned variables
varnum3:Int //withoutassignment
varnum2:220//withassignmentbut withouttype
var name = “Manish”

Question:how towrite'Kotlin' functions?
Answer:Wewrite'Kotlin' function with 'fun' keywordandargumentswith ':'keyword.

An Example of 'Kotlin' function toadd2number-

fun sum(num1:Int,num2:Int):Int {
returnnum1+num2
}

Question:How tousecomment lines in 'Kotlin'?
Answer:It is the same as Java and other programming languages:

i)SinglelineorEndoflinecomment
//Thisistest commentline

ii)Multiline or Block
/*Thisis multiline test
Comment for
Kotlin*/

=======Let us take some examples for better understanding======
1)HelloKotlin

class HelloKotlin

/*Kotlin fun with

Androidhub4you.com*/

fun main()

{

println("Hello from Androidhub4you.com")

}

Output: Hello from Androidhub4you.com

2)IfElseKotlin

class IfElseKotlin

/*Kotlin fun with

Androidhub4you.com*/

val num1: Int = 50

val num2: Int = 60

fun main()

{

if (num1 > num2)

{

println("num1 is greater than num2")

}

else

{

println("num1 is smaller than num2")

}

Output: num1 is smaller than num2

3)WhileLoopKotlin

class WhileLoopKotlin

/*Kotlin fun with

Androidhub4you.com*/

fun main()

{

var start = 1 //use 'var' as we want to do increment on start-varaiable

val max = 10 //use 'val' as we just want to comparaisen with max-varaible

while (start <= max)

{

println(start)

start++

}

Output:

Sunday, January 31, 2016

Android Material Design Demo | Android Lolypop Material Design Example | Material Design Collaps Layout | Material Design SnackBar

Hello Friends,
Here a useful example for android material design, important steps are given below-

1)Create a new android project using visual studio.
2)open your build.gradle file from src folder and import below dependencies-

compile 'com.android.support:design:22.2.1'compile 'com.android.support:cardview-v7:22.2.1'

3) And now import full code from GIT-HUB and modify according to your use-

https://github.com/manishsri01/MaterialDesign

Important Code:
1)Calling fragments from navigation drawer-

@Overridepublic void onNavigationDrawerItemSelected(int position) { // update the main content by replacing fragments

 FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); switch (position) { case 0: FloatingFragment homeFragment = new FloatingFragment(); transaction.replace(R.id.container, homeFragment); transaction.commit(); break; case 1: SnackBarFragment snackbar = new SnackBarFragment(); transaction.replace(R.id.container, snackbar); transaction.commit(); break; case 2: CollapsFragment collasps = new CollapsFragment(); transaction.replace(R.id.container, collasps); transaction.commit(); break; }}

2)Ssnackbar action-

package com.android.materialdesign.fragment;import android.os.Bundle;import android.support.design.widget.FloatingActionButton;import android.support.design.widget.Snackbar;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Toast;import com.android.materialdesign.R;public class SnackBarFragment extends Fragment { @Override public void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { final View v = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_snackbar, container, false); FloatingActionButton fab = (FloatingActionButton)v.findViewById(R.id.fab); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Snackbar.make(v.findViewById(R.id.coordinatorLayout), "I am a Snackbar",

 Snackbar.LENGTH_LONG).setAction("Action", new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(getActivity(), "Snackbar Action", Toast.LENGTH_LONG).show(); } }).show(); } }); return v; }}

3)Floating point-

package com.android.materialdesign.fragment;import android.os.Bundle;import android.support.design.widget.FloatingActionButton;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Toast;import com.android.materialdesign.R;public class FloatingFragment extends Fragment { @Override public void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_floating, container, false); FloatingActionButton fab = (FloatingActionButton)v.findViewById(R.id.fab); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(getActivity(),"work in progress..",Toast.LENGTH_SHORT).show(); } }); return v; }}

DOWNLOAD ZIP CODE

Thanks,
Manish

atJanuary 31, 20163 comments:

Labels:Android,Android Developer,androidhub4you,Material Design

Monday, December 28, 2015

PHP Web-Services to Return JSON Array | PHP Web services | Simple JSON Array web services

<?php
//open database connection
$con = mysql_connect('localhost','root','root') or die('Cannot connect to the DB');
mysql_select_db('mydb',$con);

//make a sql query to store data
$sql="SELECT * from `mydb`.`user`";
$qur=mysql_query($sql);

//check the database response is it true or false
if($qur){
if (mysql_num_rows($qur)>0) {
//write data into json array
$info = array();

while ($row = mysql_fetch_assoc($qur))
{
$arr = array();
$arr["name"] = $row["name"];
$arr["email"] = $row["email"];
$info[] = $arr;
}

$json=array("status"=>1,"message"=>"done","result"=>$info);

}
else{
$json=array("status"=>0,"message"=>"No Record found!");
}
}
else{
$json=array("status"=>0,"message"=>"error");
}

OutPut:

{
"status": 1,
"message": "done",
"result": [
{
"name": "manish",
"email": "manish@gmail.com"
},
{
"name": "Test",
"email": "test@tes.com"
}
]
}

Thanks,
Manish

atDecember 28, 2015No comments:

Labels:JSON Array,PHP,Web Services,Web-Services

Thursday, November 26, 2015

PHP Login web service | PHP code for login | PHP Simple webservices

<?php
//take the values from client as json
$json = file_get_contents('php://input');
//open database connection
$con = mysql_connect('localhost','root','root') or die('Cannot connect to the DB');
mysql_select_db('mydb',$con);
//take json values into data variable
$data = json_decode($json);

//make a sql query to store data
$sql="SELECT * from `mydb`.`user` WHERE email = '".$data->{'email'}."' AND password = '".$data->{'password'}."'";
$qur=mysql_query($sql);

//check the database response it is true or false
if($qur){
if (mysql_num_rows($qur)>= 1 ) {
$json=array("status"=>1,"message"=>"done");
}
else{
$json=array("status"=>0,"message"=>"email or password not match!");
}
}
else{
$json=array("status"=>0,"message"=>"error");
}
//close the database connection
mysql_close($con);
//set header
header('Content-type: application/json');
//print the result as json object
echo json_encode($json);
?>

atNovember 26, 2015No comments:

Labels:Login,MySql,PHP,Web Services

Sunday, October 18, 2015

Android Fragmnet Example code with full stack maintain | Fragment demo application | Simple Fragment example with action bar back button stack handle

Hello Friends,

Today I am going to share code for how to create android fragment and how to handle back stack. Have a look at below code or you can download full code from GIT server.

1)LoginActivity.java-

package com.androidhub4you.fragmentdemo;

import android.content.Intent;

import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.view.View;

public class LoginActivity extends ActionBarActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_login);

findViewById(R.id.button__activity_main).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

Intent mIntent=new Intent(LoginActivity.this,MainActivity.class);

startActivity(mIntent);

}

});

}

2)activity_login.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context=".MainActivity">

<TextView

android:layout_width="wrap_content"

android:text="Login Activity"

android:textSize="26sp"

android:textStyle="bold"

android:layout_marginTop="20dp"

android:layout_centerHorizontal="true"

android:layout_height="wrap_content" />

<TextView

android:layout_above="@+id/button__activity_main"

android:layout_width="match_parent"

android:text="(From Login Activity we will open Main Activity and inside Main Activity we will add Main Fragment in container)"

android:textSize="18sp"

android:textStyle="bold"

android:gravity="center"

android:layout_marginBottom="50dp"

android:layout_centerHorizontal="true"

android:layout_height="wrap_content" />

<Button

android:id="@+id/button__activity_main"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:paddingBottom="15dp"

android:text="Open Main Activity"

android:textSize="20sp"

android:layout_centerInParent="true"

android:paddingTop="15dp" />

</RelativeLayout>

3)MainActivity.java-

package com.androidhub4you.fragmentdemo;import android.app.FragmentTransaction;import android.os.Bundle;import android.support.v7.app.ActionBar;import android.support.v7.app.ActionBarActivity;import android.util.Log;import android.view.KeyEvent;import android.view.Menu;import android.view.MenuItem;/** * Manish Srivastava */public class MainActivity extends ActionBarActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.v("<<main activity>>", "<<screen>>"); //display home back button ActionBar actionBar = getSupportActionBar(); actionBar.setDisplayShowHomeEnabled(true); actionBar.setDisplayHomeAsUpEnabled(true); //In side Create method of MainActivity we will add main fragment FragmentTransaction transaction = getFragmentManager().beginTransaction(); FragmentMain fragmentMain = new FragmentMain(); transaction.addToBackStack("fragmentMain"); transaction.replace(R.id.container, fragmentMain); transaction.commit(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: handleBackStack(); break; case R.id.action_settings: //do nothing break; } return super.onOptionsItemSelected(item); } //handle back stack from hardware back button and top action bar home back button public boolean handleBackStack() { //on back press check the count of fragment in stack int count = getFragmentManager().getBackStackEntryCount(); Log.v("<<Fragment in stack>>",String.valueOf(count)); if (count == 1) { //if count is 0 then finish main activity finish(); }else { //else remove one fragment from the stack FragmentTransaction transaction = getFragmentManager().beginTransaction(); getFragmentManager().popBackStackImmediate(); transaction.commit(); } return true; } //set action bar title name   public void setActionBarTitle(String title) { getSupportActionBar().setTitle(title); } //handle the hardware back press @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(keyCode==KeyEvent.KEYCODE_BACK){ handleBackStack(); return true; } return super.onKeyDown(keyCode, event); }}
4)activity_main.xml-

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <FrameLayout android:id="@+id/container" android:layout_width="match_parent" android:layout_height="match_parent" /></RelativeLayout>5)FragmentMain.java-

package com.androidhub4you.fragmentdemo;import android.app.FragmentTransaction;import android.os.Bundle;import android.app.Fragment;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;/** * Manish Srivastava */public class FragmentMain extends Fragment { public FragmentMain() { // Required empty public constructor } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment View view = inflater.inflate(R.layout.fragment_main, container, false); final Button mButtonFragmentMain=(Button)view.findViewById(R.id.button__fragment_main); Log.v("<< main fragment>>","<<screen>>"); mButtonFragmentMain.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //call the child fragment FragmentTransaction transaction = getFragmentManager().beginTransaction(); FragmentChild fragmentChild = new FragmentChild(); transaction.addToBackStack("fragmentChild"); transaction.replace(R.id.container, fragmentChild); transaction.commit(); } }); //call the main activity set tile method ((MainActivity)getActivity()).setActionBarTitle("Home Fragment"); return view; }}

6)fragment_main.xml-

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="20dp" android:text="Main Fragment Screen" android:textSize="26sp" android:textStyle="bold" /> <Button android:id="@+id/button__fragment_main" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_centerInParent="true" android:paddingBottom="15dp" android:paddingTop="15dp" android:text="Open Child Fragment" android:textSize="20sp" /></RelativeLayout>

7)FragmentChild.java-

package com.androidhub4you.fragmentdemo;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;/** * Manish Srivastava */public class FragmentChild extends Fragment { public FragmentChild() { // Required empty public constructor } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment View view = inflater.inflate(R.layout.fragment_child, container, false); //call the main activity set tile method ((MainActivity)getActivity()).setActionBarTitle("Child Fragment"); return view; }}

8)fragment_child.xml-

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="Child Fragment Screen" android:textSize="26sp" android:textStyle="bold" /></RelativeLayout>

DOWNLOAD FULL CODE

Thanks!

Manish

atOctober 18, 20154 comments:

Labels:Android,androidhub4you,Fragment