android:layout_width="fill_parent"
android:layout_height="fill_parent" >
android:id="@+id/txtResultId"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:editable="false"
android:gravity="right" />
android:id="@+id/tableId"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/txtResultId" android:layout_marginTop="60dp">
android:id="@+id/btnNum7Id"
android:text="7"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum8Id"
android:text="8"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum9Id"
android:text="9"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnDivId"
android:text="÷"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum4Id"
android:text="4"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum5Id"
android:text="5"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum6Id"
android:text="6"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnMulId"
android:text="×"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnNum1Id"
android:text="1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />
android:id="@+id/btnNum2Id"
android:text="2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnNum3Id"
android:text="3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnSubId"
android:text="-"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnNum0Id"
android:text="0"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnClearId"
android:text="C"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnEqualId"
android:text="="
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
android:id="@+id/btnAddId"
android:text="+"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
calc.java
package com.exam;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class calc extends Activity implements OnClickListener {
private EditText txtResult; // Reference to EditText of result
private int result = 0; // Result of computation
private String inStr = "0"; // Current input string
// Previous operator: '+', '-', '*', '/', '=' or ' ' (no operator)
private char lastOperator = ' ';
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Retrieve a reference to the EditText field for displaying the result.
txtResult = (EditText)findViewById(R.id.txtResultId);
txtResult.setText("0");
// Register listener (this class) for all the buttons
((Button)findViewById(R.id.btnNum0Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum1Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum2Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum3Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum4Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum5Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum6Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum7Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum8Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnNum9Id)).setOnClickListener(this);
((Button)findViewById(R.id.btnAddId)).setOnClickListener(this);
((Button)findViewById(R.id.btnSubId)).setOnClickListener(this);
((Button)findViewById(R.id.btnMulId)).setOnClickListener(this);
((Button)findViewById(R.id.btnDivId)).setOnClickListener(this);
((Button)findViewById(R.id.btnClearId)).setOnClickListener(this);
((Button)findViewById(R.id.btnEqualId)).setOnClickListener(this);
}
// On-click event handler for all the buttons
@Override
public void onClick(View view) {
switch (view.getId()) {
// Number buttons: '0' to '9'
case R.id.btnNum0Id:
case R.id.btnNum1Id:
case R.id.btnNum2Id:
case R.id.btnNum3Id:
case R.id.btnNum4Id:
case R.id.btnNum5Id:
case R.id.btnNum6Id:
case R.id.btnNum7Id:
case R.id.btnNum8Id:
case R.id.btnNum9Id:
String inDigit = ((Button)view).getText().toString();
if (inStr.equals("0")) {
inStr = inDigit; // no leading zero
} else {
inStr += inDigit; // accumulate input digit
}
txtResult.setText(inStr);
// Clear buffer if last operator is '='
if (lastOperator == '=') {
result = 0;
lastOperator = ' ';
}
break;
// Operator buttons: '+', '-', '*', '/' and '='
case R.id.btnAddId:
compute();
lastOperator = '+';
break;
case R.id.btnSubId:
compute();
lastOperator = '-';
break;
case R.id.btnMulId:
compute();
lastOperator = '*';
break;
case R.id.btnDivId:
compute();
lastOperator = '/';
break;
case R.id.btnEqualId:
compute();
lastOperator = '=';
break;
// Clear button
case R.id.btnClearId:
result = 0;
inStr = "0";
lastOperator = ' ';
txtResult.setText("0");
break;
}
}
// User pushes '+', '-', '*', '/' or '=' button.
// Perform computation on the previous result and the current input number,
// based on the previous operator.
private void compute() {
int inNum = Integer.parseInt(inStr);
inStr = "0";
if (lastOperator == ' ') {
result = inNum;
} else if (lastOperator == '+') {
result += inNum;
} else if (lastOperator == '-') {
result -= inNum;
} else if (lastOperator == '*') {
result *= inNum;
} else if (lastOperator == '/') {
result /= inNum;
} else if (lastOperator == '=') {
// Keep the result for the next operation
}
txtResult.setText(String.valueOf(result));
}
}
