サンプル
MainActivity.java
import android.content.ClipData;
import android.content.ClipDescription;
import android.content.ClipboardManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.math.BigDecimal;
import java.text.DecimalFormat;
public class MainActivity extends AppCompatActivity {
private static final String ZERO = "0";
private static final String DECIMAL = ".";
private static final String FORMAT = "#,##0";
private static final int INITIAL_FOR_ID = -1;
private DecimalFormat format;
private String inputTemporaryData = "";
private String resultData = "";
private int operatorId = INITIAL_FOR_ID;
public MainActivity() {
this.format = new DecimalFormat(FORMAT);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public void onStop() {
super.onStop();
}
@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) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void numberOrDecimalKeyOnClick(View view) {
Button button = (Button)view;
String inputKeyText = (String) button.getText();
if (!DECIMAL.equals(inputKeyText)) {
this.inputTemporaryData = this.inputTemporaryData + inputKeyText;
} else {
if (this.inputTemporaryData.length() == 0) {
this.inputTemporaryData = ZERO + DECIMAL;
} else if (this.inputTemporaryData.indexOf(DECIMAL) == -1) {
this.inputTemporaryData = this.inputTemporaryData + DECIMAL;
}
}
this.showNumber(this.inputTemporaryData);
}
public void functionKeyOnClick(View view) {
switch (view.getId()) {
case R.id.allClearButton:
this.inputTemporaryData = "";
this.resultData = "";
this.getSubTextView().setText("");
break;
case R.id.copyButton:
this.copyOnClipboard(this.getDisplayTextView().getText().toString());
break;
case R.id.backSpaceButton:
if (this.inputTemporaryData.length() != 0) {
this.inputTemporaryData =
this.inputTemporaryData.substring(0, this.inputTemporaryData.length() - 1);
}
break;
}
this.showNumber(this.inputTemporaryData);
}
public void operatorKeyOnClick(View view) {
TextView subTextView = this.getSubTextView();
int viewId = view.getId();
Button currentOperatorButton = (Button)super.findViewById(viewId);
String currentOperator = currentOperatorButton.getText().toString();
if (this.operatorId != INITIAL_FOR_ID) {
if (this.inputTemporaryData.length() > 0) {
Button previousOperatorButton = (Button)super.findViewById(this.operatorId);
String previousOperator = previousOperatorButton.getText().toString();
subTextView.setText(this.resultData + previousOperator +
this.inputTemporaryData + currentOperator);
this.resultData = this.getCalculationResult();
this.showNumber(this.resultData);
} else {
subTextView.setText(this.resultData + currentOperator);
}
} else {
if (this.inputTemporaryData.length() > 0) {
this.resultData = this.inputTemporaryData;
}
subTextView.setText(this.resultData + currentOperator);
}
// Reset Parameters
this.inputTemporaryData = "";
if (viewId == R.id.equalButton) {
this.operatorId = INITIAL_FOR_ID;
} else {
this.operatorId = viewId;
}
}
private String getCalculationResult() {
BigDecimal result = new BigDecimal(this.resultData);
BigDecimal temporary = new BigDecimal(this.inputTemporaryData);
BigDecimal returnValue = BigDecimal.ZERO;
switch (this.operatorId) {
case R.id.addButton:
// +
returnValue = result.add(temporary);
break;
case R.id.subtractButton:
// -
returnValue = result.subtract(temporary);
break;
case R.id.multiplyButton:
// *
returnValue = result.multiply(temporary);
break;
case R.id.divideButton:
// /
if (!BigDecimal.ZERO.equals(temporary)) {
returnValue = result.divide(temporary);
} else {
Toast toast =Toast.makeText(
this, R.string.error_divide_by_zero, Toast.LENGTH_SHORT);
toast.show();
}
break;
}
if (returnValue.toString().indexOf(DECIMAL) >= 0) {
return returnValue.toString().replaceAll("\\.0+$|0+$", "");
} else {
return returnValue.toString();
}
}
private void showNumber(String number) {
String shownNumber;
if (number.length() > 0) {
int decimalPointIndex = number.indexOf(DECIMAL);
if (decimalPointIndex > -1) {
String decimalNumber = number.substring(decimalPointIndex);
String integerPart = number.substring(0, decimalPointIndex);
shownNumber = this.format.format(Double.parseDouble(integerPart)) + decimalNumber;
} else {
shownNumber = this.format.format(Double.parseDouble(number));
}
} else {
shownNumber = ZERO;
}
this.getDisplayTextView().setText(shownNumber);
}
private void copyOnClipboard(String copiedText) {
String[] mimeTypes = new String[1];
mimeTypes[0] = ClipDescription.MIMETYPE_TEXT_URILIST;
ClipData.Item clipDataItem = new ClipData.Item(copiedText);
ClipData clipData = new ClipData(new ClipDescription(copiedText, mimeTypes), clipDataItem);
ClipboardManager clipboardManager =
(ClipboardManager)super.getSystemService(CLIPBOARD_SERVICE);
clipboardManager.setPrimaryClip(clipData);
}
private TextView getDisplayTextView() {
return (TextView)super.findViewById(R.id.displayTextView);
}
private TextView getSubTextView() {
return (TextView)super.findViewById(R.id.subTextView);
}
}
strings.xml
<resources>
<string name="app_name">SampleCalculator</string>
<string name="error_divide_by_zero">You cannot divide by Zero...</string>
<string name="action_settings">Settings</string>
</resources>
