Cara Membuat Kalkulator Dengan Java
Dibawah ini panduan singkat bagaimana cara membuat kalkulator dengan menggunakan perintah java.
Copykan kode dibawah ini ke file layout
Copykan code dibawah ini kedalam file
Copykan kode dibawah ini ke file layout
activity_main.xml<layout>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
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="com.sample.foo.samplecalculator.MainActivity">
<TextView
android:id="@+id/infoTextView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="30dp"
android:textSize="30sp" />
<EditText
android:id="@+id/editText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/infoTextView"
android:enabled="false"
android:gravity="bottom"
android:lines="2"
android:maxLines="2"
android:textSize="20sp" />
<Button
android:id="@+id/buttonSeven"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/editText"
android:text="7"
android:textSize="20sp" />
<Button
android:id="@+id/buttonEight"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/editText"
android:layout_toRightOf="@id/buttonSeven"
android:text="8"
android:textSize="20sp" />
<Button
android:id="@+id/buttonNine"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/editText"
android:layout_toRightOf="@id/buttonEight"
android:text="9"
android:textSize="20sp" />
...
...
<Button
android:id="@+id/buttonDot"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/buttonOne"
android:text="."
android:textSize="20sp" />
<Button
android:id="@+id/buttonZero"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@id/buttonEight"
android:layout_below="@id/buttonTwo"
android:text="0"
android:textSize="20sp" />
<Button
android:id="@+id/buttonEqual"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@id/buttonNine"
android:layout_below="@id/buttonThree"
android:text="="
android:textSize="20sp" />
<Button
android:id="@+id/buttonDivide"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@id/buttonNine"
android:layout_toRightOf="@id/buttonNine"
android:text="/"
android:textSize="20sp" />
<Button
android:id="@+id/buttonMultiply"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@id/buttonSix"
android:layout_toRightOf="@id/buttonSix"
android:text="*"
android:textSize="20sp" />
<Button
android:id="@+id/buttonSubtract"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@id/buttonThree"
android:layout_toRightOf="@id/buttonThree"
android:text="-"
android:textSize="20sp" />
<Button
android:id="@+id/buttonAdd"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@id/buttonEqual"
android:layout_toRightOf="@id/buttonEqual"
android:text="+"
android:textSize="20sp" />
<Button
android:id="@+id/buttonClear"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@id/buttonAdd"
android:layout_below="@id/buttonAdd"
android:layout_marginTop="@dimen/activity_vertical_margin"
android:text="C"
android:textSize="20sp" />
</RelativeLayout>
</layout>Copykan code dibawah ini kedalam file
MainActivity.javapackage com.sample.foo.samplecalculator;
import android.databinding.DataBindingUtil;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import com.sample.foo.samplecalculator.databinding.ActivityMainBinding;
import java.text.DecimalFormat;
public class MainActivity extends AppCompatActivity {
private ActivityMainBinding binding;
private static final char ADDITION = '+';
private static final char SUBTRACTION = '-';
private static final char MULTIPLICATION = '*';
private static final char DIVISION = '/';
private char CURRENT_ACTION;
private double valueOne = Double.NaN;
private double valueTwo;
private DecimalFormat decimalFormat;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
decimalFormat = new DecimalFormat("#.##########");
binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.buttonDot.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + ".");
}
});
binding.buttonZero.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "0");
}
});
binding.buttonOne.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "1");
}
});
binding.buttonTwo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "2");
}
});
binding.buttonThree.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "3");
}
});
binding.buttonFour.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "4");
}
});
binding.buttonFive.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "5");
}
});
binding.buttonSix.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "6");
}
});
binding.buttonSeven.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "7");
}
});
binding.buttonEight.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "8");
}
});
binding.buttonNine.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
binding.editText.setText(binding.editText.getText() + "9");
}
});
binding.buttonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
computeCalculation();
CURRENT_ACTION = ADDITION;
binding.infoTextView.setText(decimalFormat.format(valueOne) + "+");
binding.editText.setText(null);
}
});
binding.buttonSubtract.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
computeCalculation();
CURRENT_ACTION = SUBTRACTION;
binding.infoTextView.setText(decimalFormat.format(valueOne) + "-");
binding.editText.setText(null);
}
});
binding.buttonMultiply.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
computeCalculation();
CURRENT_ACTION = MULTIPLICATION;
binding.infoTextView.setText(decimalFormat.format(valueOne) + "*");
binding.editText.setText(null);
}
});
binding.buttonDivide.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
computeCalculation();
CURRENT_ACTION = DIVISION;
binding.infoTextView.setText(decimalFormat.format(valueOne) + "/");
binding.editText.setText(null);
}
});
binding.buttonEqual.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
computeCalculation();
binding.infoTextView.setText(binding.infoTextView.getText().toString() +
decimalFormat.format(valueTwo) + " = " + decimalFormat.format(valueOne));
valueOne = Double.NaN;
CURRENT_ACTION = '0';
}
});
binding.buttonClear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(binding.editText.getText().length() > 0) {
CharSequence currentText = binding.editText.getText();
binding.editText.setText(currentText.subSequence(0, currentText.length()-1));
}
else {
valueOne = Double.NaN;
valueTwo = Double.NaN;
binding.editText.setText("");
binding.infoTextView.setText("");
}
}
});
}
private void computeCalculation() {
if(!Double.isNaN(valueOne)) {
valueTwo = Double.parseDouble(binding.editText.getText().toString());
binding.editText.setText(null);
if(CURRENT_ACTION == ADDITION)
valueOne = this.valueOne + valueTwo;
else if(CURRENT_ACTION == SUBTRACTION)
valueOne = this.valueOne - valueTwo;
else if(CURRENT_ACTION == MULTIPLICATION)
valueOne = this.valueOne * valueTwo;
else if(CURRENT_ACTION == DIVISION)
valueOne = this.valueOne / valueTwo;
}
else {
try {
valueOne = Double.parseDouble(binding.editText.getText().toString());
}
catch (Exception e){}
}
}
}
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