I want to transition screens with kotlin and java!

Introduction ...

This article was written in 4 previous articles,

** 5th day of article posting every day for 7 days **

It has become

I'll put the code to use below, but see the article four before for the detailed features of this app!

--java version: https://github.com/sato-na/guruwake_java

--kotlin version: https://github.com/sato-na/guruwake_kotlin

↓ This is the main subject of this article ↓

To make screen transitions in each language ...

Basics of screen transition

--For java

Intent intent = new intent(Pre-transition activity.this,Post-transition activity.class);
startActivity(intent);

Example)

MainActivity.java

Intent intent = new Intent(MainActivity.this, WhoActivity.class);  //25th line
startActivity(intent);

--For kotlin

val intent = Intent(application,Post-transition activity::class.java)
startActivity(intent)

Example)

MainActivity.kt

val intent = Intent(application, WhoActivity::class.java)  //18th line
startActivity(intent)

The intent setting method is very different

How to pass a character string at the time of screen transition

--For java

(Activity before transition)

Intent intent = new Intent(Current activity.this,Next activity.class);
intent.putExtra("Key associated with the value",Value you want to pass);
startActivity(intent);

Example)

HowManyActivity.java

String groupNum = groupNumE.getText().toString();                           //Line 43
Intent intent = new Intent(WhoActivity.this, HowManyActivity.class);        //Line 46
intent.putExtra("GROUP_NUM", groupNum);    //Send groupNum to CheckActivity//Line 48
startActivity(intent);

(Activity after transition)

Intent intent = getIntent();
final String variable name= intent.getStringExtra("Key associated with the value");

Example)

CheckActivity.java

Intent intent = getIntent();                                 //25th line
final String groupNum = intent.getStringExtra("GROUP_NUM");  //27th line

--For kotlin

(Activity before transition)

val intent = Intent(application,Post-transition activity::class.java)
intent.putExtra("Key associated with the value",Value you want to pass)
startActivity(intent)

Example)

HowManyActivity.kt

val groupNum = group_num_et.text.toString()                               //Line 33
val intent = Intent(application, CheckActivity::class.java)               //36th line
intent.putExtra("GROUP_NUM", groupNum)   //Send groupNum to CheckActivity//38th line
startActivity(intent)

(Activity after transition)

val variable name= intent.getStringExtra("Key associated with the value")

Example)

CheckActivity.kt

val groupNum = intent.getStringExtra("GROUP_NUM")

The code to receive the value to write in the activity after the transition is different

How to make a screen transition by pressing a button

--For java

Button variable name= findViewById(R.id.Button id);
variable.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        //Screen transition
    }
});

Example)

MainActivity.java

Button startButton = findViewById(R.id.start_btn);  //Line 19
startButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent intent = new Intent(MainActivity.this, WhoActivity.class);
        startActivity(intent);
    }
});

--For kotlin

Button id.setOnClickListener {
    //Screen transition
}

Example)

MainActivity.kt

start_btn.setOnClickListener {  //16th line
    val intent = Intent(application, WhoActivity::class.java)
    startActivity(intent)
}

Overall, kotlin requires less code than java when dealing with buttons

Finally…

This time, I pressed the button with java and kotlin to change the screen. Overall, I had the impression that kotlin was easier to write than java.

I will post an article tomorrow, so please keep an eye on me.