Showing posts with label TUTORIALS. Show all posts
Showing posts with label TUTORIALS. Show all posts

Tuesday 13 June 2017

Simple Calculator app in Android

25 comments :
Simple Calculator app in Android

Download Source Code


This post is similar to that of 

Adding two numbers in Android

 We are using different operations like subtraction, multiplication,division and also addition.

Read Working with Multiple Buttons


This example is the combination of the last two post

Adding two numbers in Android and Working with Multiple buttons,so if you have practiced that well this program is easy for you or else practice that both examples and continue this example.


We need to make the design plan.

Simple-Calculator-app-in-Android
Create a new project and Just drag and drop and edit as per in the design.

Simple-Calculator-app-in-Android

The number 1 and Number 2 can be typed using the help of hint property.

To use the hint right click on the Plain Text  and EditHint

add-hint

Then register the buttons,edittext's, textview's in MainActivity.java

onclick-method


After that add switch case statement  as in the last post and include the addition of two numbers example code and also include code for other operations also as in the image.

Simple-Calculator-app-in-Android-source-code

I think it is very easy to understand right! yeah it's so simple to develop android apps than you think if you have basic programming concepts and interest to learn!!!

Let we see the Output

Simple-Calculator-app-in-Android-output

Simple-Calculator-app-in-Android-output


When clicked ADD Button

Simple-Calculator-app-in-Android-output
When Clicked SUB Button

Simple-Calculator-app-in-Android-output
When clicked MUL button

Simple-Calculator-app-in-Android-output
When clicked DIV Button

Simple-Calculator-app-in-Android-output

How to use Android Phone as an Emulator



Practice this example more times and do it without referring any example codes.

It will make you to have strong knowledge in working with buttons.


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Working with multiple buttons in Android

3 comments :
Working-with-multiple-buttons-in-Android

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In this post you can learn how to work with multiple buttons , before that read how to work with buttons.

It is similar to that of working with buttons the difference is that we are going to work with multiple buttons .

We are just going to use a SWITCH case where the button id's are used in case: .

Let us start the project.

Open New Project and make a user interface by dragging dropping the buttons where you want , I recommend you to read the below two post to get grip on the Buttons.

How to display names using Button in Android 

Adding two numbers in Android

 After designing the user interface it will look like 

working-with-multiple-buttons

Edit the names of the buttons as Button 1, Button 2, Button 3 respectively.

Right click on the button to Edit Text.
renaming-button-name-in-android


resolving-warning


Do the same for all the buttons

renaming-button-names

Read how to remove the warning symbol 


resolving-warning

After that we need to start java coding.

We need to register these three buttons and implement the interface and add unimplemented methods

button-code-in-android

After that inside the onclick method we need to write the switch condition.

working-with-multiple-buttons-in-android-java-code

This code is similar to that of switch case examples in c programs ,

the v.getId() will give you the id of the clicked button.

The other codes are similar to the previous posts.

The output will be:

working-with-multiple-buttons-in-android-output

working-with-multiple-buttons-in-android-output

working-with-multiple-buttons-in-android-output

working-with-multiple-buttons-in-android-output

How to use Android Phone as an Emulator


Working with multiple buttons in android will be useful in the upcoming examples so practice this example well and try your own ideas and practice that too.


Code of onClick() method:

public void onClick(View v)
    {
        switch (v.getId())
        {
        case R.id.button1:
           
            Toast.makeText(getApplicationContext(), "Button 1 is clicked", Toast.LENGTH_LONG).show();
           
            break;
           
        case R.id.button2:
           
            Toast.makeText(getApplicationContext(), "Button 2 is clicked", Toast.LENGTH_LONG).show();
           
            break;
           
         case R.id.button3:
   
            Toast.makeText(getApplicationContext(), "Button 3 is clicked", Toast.LENGTH_LONG).show();
   
            break;

        default:
            break;
        }
    }
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Monday 12 June 2017

Adding two numbers in Android

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adding-numbers-in-android




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In this post you can learn how to add two numbers in android.

Before that i recommend to read the below button example post to get an idea about working with buttons.

How to work with buttons in android

How to display names while button is clicked in android.


As in my last i have said that before starting the design we need to draw what we are going to design.

ui-design


Create a New Project and drag and drop two EditText for getting inputs from the user and a Button to calculate addition operation and a TextView to display the Result.


primary-ui-design


Read this post to remove the warnings How to display names while button is clicked in android. 

warning-cleared-ui

Next we need to start the coding part.

The registering the edittext , Textview, Button is same as the previous posts.

button-code

After that we need to declare variables to get the numbers and store the result value.

we define it in double.

double number1,number2,sum;

Then type the following code

addition-of-two-numbers-android-code
 

the last lines in the code is just converting the string in to double for calculation.

Then after typing the code Run the program.

Output:


output

output
output
output



Read How to run android program in your mobile

 Code of onClick() method:

public void onClick(View arg0)
    {
       
        number1=Double.parseDouble( num1.getText().toString());
        number2=Double.parseDouble(num2.getText().toString());
        sum=number1+number2;
       
        result.setText(Double.toString(sum));
       
    }

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How to display names using Button in Android

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millioninformations-gif



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In this post we are going to display name which we are going to enter in a text field and when the button is clicked the entered name will be displayed.

First we need to create a new Project in Eclipse IDE.

File ----> New ---> Android Application Project.

Give the project name and click Next--->Next-->Next--->Next---->Finish.

While creating any Project we need to make a simple design overview of that application.

It can be drawn in Paper or in Paint application.

Here I am using the first method , drawing the design in a paper.

design-plan

project-blue-print

Like this we are going to design the User Interface.

Open activity_main.xml file under DisplayingName(ProjectName)---->res---->activity_main.xml

actvity-main

  Then find the Palette and Drag and drop the TextView element .

text-view


Then we need a place to enter the name that is called a plain text element which is found under the TextFields area.

plain-text

Next we need a Button

button

After that we need to display the entered name for that we need text view.

displaying-name

Now our required elements are placed in our project, now we need to make some editing of the elements.

First we need to rename the textview, for that we need to right click on the textview--->EditText option.

rename-text-view

Then we need to enter our desired text and click Ok.

enter-the-name

After that you can see that the edited text will appear

renamed-text-view

Like that we can edit the Button name as Show and the last TextView to empty.

edited

we can clear those warnings.

Go to values----> String .xml and open it.


Then type as in the image

editing-string-xml

After come to activity_main.xml and type as in the image.

adding-string-name

Do the same for button and give the input type as text in Edit text




Now save all the errors and warnings will be gone now.



Next we need to start coding the java part for displaying the name.

Open MainActivity.java under the src folder.

Register the button and implement the interface and override the unimplemented methods as we saw in last post

Read Post

You can see the Button ID , Text Id in activity_main.xml

The coding till the last post is


We need to register the plaintext i.e edittext and text view to get the input and display the output.


Then we need to code the button part as in the image


The code is in the image.



Then Run the Program , right click on the Project Name and click Run as---> Android application



Read how to run Android app in your Mobile

The output is







outputoutput
The code is very easy to understand






input is the name of the edittext and getText() method is used to get what ever the text that the user gives inputs and settext is to set the text we want .

MainActivity.java

 public class MainActivity extends Activity implements OnClickListener
{
     EditText input;
     TextView output;
   
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
         input=(EditText)findViewById(R.id.editText1);
         output=(TextView)findViewById(R.id.textView2);
       
       
        Button show=(Button)findViewById(R.id.button1);
        show.setOnClickListener(this);
    }

    @Override
    public void onClick(View arg0)
    {
        // TODO Auto-generated method stub
      
        String name=input.getText().toString();
        output.setText(name);
      
      
    }

This simple example will make you motivated to become an android app developer.

You find any error in this example send to my mail narain2829@gmail.com .



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