Aplikasi Kalkulator Sederhana dengan Android Studio

Nama : Gede Widya Dharma

Nim : 1404505093
Dosen : I Putu Eka Pratama ST., MT
Matakuliah : Pemograman Mobile
Kampus : Jurusan Teknologi Informasi, Fakultas Teknik Universitas Udayana

1.  Buat proyek baru. Klik Next.

2. Pilih opsi Phone and Tablet yang diinginkan. Klik Next

3. Pilih Blank Activity. Klik Next.

4. Memberi nama Activity (Main Citivty). Klik Finish.

5.  Sistem mempersiapkan proyek yang dibuat. dan halaman kerja dari Android Studio akan muncul.

6. Ketikkan script berikut pada file activity_main.xml yang berlokasi di /res/layout. Script ini untuk membangun tatap muka aplikasi.

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:shrinkColumns="*" android:stretchColumns="*" android:background="#ffffff">
<!­­ Row 1 with single column ­­>
<TableRow android:layout_height="match_parent" android:layout_width="match_parent" android:gravity="center_horizontal">
<EditText android:id="@+id/result_id" android:layout_width="match_parent" android:layout_height="match_parent" android:textSize="30dp" android:layout_span="4" android:padding="30dip" android:background="#b0b0b0" android:textColor="#000"/>
</TableRow>
<!­­ Row 2 with 4 columns ­­>
<TableRow android:id="@+id/tableRow1" android:layout_height="match_parent" android:layout_width="match_parent">
<Button android:id="@+id/Btn7_id" android:text="7" android:textSize="20dp" android:layout_weight="1" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:onClick="btn7Clicked" android:gravity="center"/>
<Button android:id="@+id/Btn8_id" android:text="8" android:textSize="20dp" android:layout_weight="1" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:onClick="btn8Clicked" android:gravity="center" />
<Button android:id="@+id/Btn9_id" android:text="9" android:textSize="20dp" android:layout_weight="1" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:onClick="btn9Clicked" android:gravity="center"/>
<Button android:id="@+id/Btnmulti_id" android:text="*" android:textSize="20dp" android:layout_weight="1" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:onClick="btnmultiClicked" android:gravity="center"/>
</TableRow>
<TableRow android:id="@+id/tableRow2" android:layout_height="match_parent" android:layout_width="match_parent">
<Button android:id="@+id/Btn4_id" android:text="4" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:textSize="20dp" android:layout_weight="1" android:onClick="btn4Clicked" android:gravity="center"/>
<Button android:id="@+id/Btn5_id" android:text="5" android:textSize="20dp" android:layout_weight="1" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:onClick="btn5Clicked" android:gravity="center"/>
<Button android:id="@+id/Btn6_id" android:text="6" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:textSize="20dp" android:layout_weight="1" android:onClick="btn6Clicked" android:gravity="center"/>
<Button android:id="@+id/Btndivide_id" android:text="/" android:layout_weight="1" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:textSize="20dp" android:onClick="btndivideClicked" android:gravity="center"/>
</TableRow>
<TableRow android:id="@+id/tableRow3" android:layout_height="match_parent" android:layout_width="match_parent">
<Button android:id="@+id/Btn1_id" android:text="1" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:layout_weight="1" android:textSize="20dp" android:onClick="btn1Clicked" android:gravity="center"/>
<Button android:id="@+id/Btn2_id" android:text="2" android:textSize="20dp" android:layout_weight="1" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:onClick="btn2Clicked" android:gravity="center"/>
<Button android:id="@+id/Btn3_id" android:text="3" android:textSize="20dp" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:layout_weight="1" android:onClick="btn3Clicked" android:gravity="center"/>
<Button android:id="@+id/Btnpersen_id" android:text="%" android:textSize="20dp" android:layout_weight="1" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:onClick="btnpersenClicked" android:gravity="center"/>
</TableRow>
<TableRow android:id="@+id/tableRow4" android:layout_height="match_parent" android:layout_width="match_parent">
<Button android:id="@+id/Btnplus_id" android:text="+" android:textSize="20dp" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:layout_weight="1" android:onClick="btnplusClicked" android:gravity="center"/>
<Button android:id="@+id/Btn0_id" android:text="0" android:textSize="20dp" android:background="#cac9c9" android:textColor="#000000" android:padding="30dip" android:layout_weight="1" android:onClick="btn0Clicked" android:gravity="center"/>
<Button android:id="@+id/Btnminus_id" android:text="­" android:textSize="20dp" android:background="#d3d3d3" android:textColor="#000000" android:padding="30dip" android:layout_weight="1" android:onClick="btnminusClicked" android:gravity="center"/>
<Button android:id="@+id/Btnequal_id" android:text="=" android:textSize="20dp" android:layout_weight="1" android:background="#b0b0b0" android:textColor="#000000" android:padding="30dip" android:onClick="btnequalClicked" android:gravity="center"/>
</TableRow>
<!­­ Row 3 with 2 columns ­­>
<TableRow android:layout_height="match_parent" android:layout_width="match_parent" android:gravity="center_horizontal" >
<Button android:id="@+id/Btnclear_id" android:text="CLEAR" android:textSize="20dp" android:layout_weight="1" android:background="#dcdcdc" android:textColor="#000000" android:padding="30dip" android:onClick="btnclearClicked" android:gravity="center"/>
<Button android:id="@+id/Btnexit_id" android:text="EXIT" android:textSize="20dp" android:layout_weight="1" android:background="#dcdcdc" android:textColor="#000000" android:padding="30dip" android:onClick="btnexitClicked" android:gravity="center"/>
</TableRow>
</TableLayout>

7. Kemudian ketikkan script Java berikut pada file main activity.java yang ada di /java/squwidy.kalkulator.

package squwidy.kalkulator;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
@Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});


public class MainActivity extends ActionBarActivity {
 public String str ="";
Character op = 'q';
float i,num,numtemp;
EditText showResult;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
showResult = (EditText)findViewById(R.id.result_id);

}
public void btn0Clicked(View v){
insert(0);
}
public void btn1Clicked(View v){
insert(1);
}
 public void btn2Clicked(View v){
insert(2);
}
public void btn3Clicked(View v){
insert(3);
}
public void btn4Clicked(View v){
insert(4);
}
public void btn5Clicked(View v){
insert(5);
}
public void btn6Clicked(View v){
  insert(6);
}
public void btn7Clicked(View v){
insert(7);
}
public void btn8Clicked(View v){
insert(8);
}
public void btn9Clicked(View v){
insert(9);
}
public void btnplusClicked(View v){
perform();
op = '+';
}
 public void btnminusClicked(View v){
perform();
op = '­';
}
public void btndivideClicked(View v){
perform();
op = '/';
}
public void btnmultiClicked(View v){
perform();
op = '*';
}
public void btnpersenClicked(View v){
perform();
op = '%';
}
public void btnequalClicked(View v){
calculate();
}
public void btnclearClicked(View v){
reset();
}
 public void btnexitClicked(View v){
exit();
}
private void reset() {
// TODO Auto­generated method stub   str ="";
op ='q';
num = 0;
numtemp = 0;
showResult.setText("");
}
public void exit()  {
 this.finish();
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
private void insert(int j) {
// TODO Auto­generated method stub   str = str+Integer.toString(j);
num = Integer.valueOf(str).intValue();
showResult.setText(str);
}
private void perform() {
// TODO Auto­generated method stub   str = "";
calculateNoShow();
numtemp = num;
}
private void calculate() {
// TODO Auto­generated method stub   if(op == '+')
num = numtemp+num;
else if(op == '­')
num = numtemp­num;
else if(op == '/')
num = numtemp/num;
else if(op == '*')
num = numtemp*num;
else if(op == '%')
num = numtemp%num;
showResult.setText(""+num);
}
 private void calculateNoShow() {
// TODO Auto­generated method stub   if(op == '+')
num = numtemp+num;
else if(op == '­')
num = numtemp­num;
else if(op == '/')
num = numtemp/num;
else if(op == '*')
num = numtemp*num;
else if(op == '%')
num = numtemp%num;
}
}

8. Tekan tombol Save (Simpan). Compile dan jalankan. Tekan tombol hijau. Aplikasi siap dijalankan.