Hello, i faced some problem in building the android calculator. The problems like this:
1) If i click 2 + 3, it worked well, and screen will show the 5.** BUT! when i clicked + and + and + and +...... it will continuosly add the answer. How can i solve it
2) if i click 2 + 3, it worked well, and screen will show the 5. **BUT! how if i 2 + - , it will perform 2 + 2 - ....
Others doesnt have any problem, anyone may help
MainActivity.java file
import java.text.DecimalFormat;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener {
private TextView disp, dispMini;
private Boolean inserting = false;
private operate operation;
private static final String digit = "0123456789.";
private static final String optr = "+-X/.";
DecimalFormat df = new DecimalFormat("@###########");
@Override
protected void onCreate(Bundle icicle) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); // hide the status bar and other
super.onCreate(icicle);
setContentView(R.layout.activity_main);
operation = new operate();
disp = (TextView) findViewById(R.id.disp);
dispMini = (TextView) findViewById(R.id.dispMini);
df.setMinimumFractionDigits(0); //automatically set fraction to 0 (0.0)
df.setMinimumFractionDigits(1); //automatically set fraction to 1 (0.1)
df.setMinimumFractionDigits(8); //automatically set faction to 8 (0.11111111)
findViewById(R.id.btn1).setOnClickListener(this);
findViewById(R.id.btn2).setOnClickListener(this);
findViewById(R.id.btn3).setOnClickListener(this);
findViewById(R.id.btn4).setOnClickListener(this);
findViewById(R.id.btn5).setOnClickListener(this);
findViewById(R.id.btn6).setOnClickListener(this);
findViewById(R.id.btn7).setOnClickListener(this);
findViewById(R.id.btn8).setOnClickListener(this);
findViewById(R.id.btn9).setOnClickListener(this);
findViewById(R.id.btn0).setOnClickListener(this);
findViewById(R.id.btnAdd).setOnClickListener(this);
findViewById(R.id.btnSub).setOnClickListener(this);
findViewById(R.id.btnMul).setOnClickListener(this);
findViewById(R.id.btnDiv).setOnClickListener(this);
findViewById(R.id.btnDot).setOnClickListener(this);
findViewById(R.id.btnToggle).setOnClickListener(this);
findViewById(R.id.btnEquals).setOnClickListener(this);
findViewById(R.id.btnClear).setOnClickListener(this);
findViewById(R.id.btnMod).setOnClickListener(this);
findViewById(R.id.btnSquared).setOnClickListener(this);
findViewById(R.id.btnCube).setOnClickListener(this);
findViewById(R.id.btnSquareRoot).setOnClickListener(this);
findViewById(R.id.btnOver).setOnClickListener(this);
findViewById(R.id.btnDel).setOnClickListener(this);
}
@Override
public void onClick(View v) {
final Animation animAlpha = AnimationUtils.loadAnimation(this, R.anim.anim_alpha);
String buttonPressed = ((Button) v).getText().toString();
v.startAnimation(animAlpha);
if (digit.contains(buttonPressed)) {
if (inserting) {
if (buttonPressed.equals(".") && disp.getText().toString().contains(".")) { //to prevent entering multiple dot
}
else {
disp.append(buttonPressed);
}
}
else {
if (buttonPressed.equals(".")) {
disp.setText(0 + buttonPressed); //add zero to the front if dot is entered (means .3 will become 0.3)
}
else {
disp.setText(buttonPressed);
}
inserting = true;
}
}
else if(v.getId() == R.id.btnDel) //if backspace button ("DEL") is clicked, delete one number
{
String toDelete = disp.getText().toString();
if(toDelete.length() > 1) {
toDelete = toDelete.substring(0, toDelete.length() - 1);
disp.setText(toDelete);
}
else if(toDelete.length() <=1){
disp.setText("0");
}
}
else {
//to display the all input value and operator in minimized view
if(optr.contains(buttonPressed)) {
if (dispMini.getText() != null) {
String str1 = dispMini.getText().toString();
String str2 = disp.getText().toString();
dispMini.setText(str1.concat(str2.concat(buttonPressed)));
} else {
String str = disp.getText().toString();
dispMini.setText(str.concat(buttonPressed));
}
}
//do the operation
if (inserting) {
operation.setOperand(Double.parseDouble(disp.getText().toString()));
inserting = false;
}
operation.performOperation(buttonPressed);
disp.setText(df.format(operation.getResult()));
}
if(v.getId() == R.id.btnClear || v.getId()==R.id.btnEquals) //clean textview if clean button or equal button clicked
{
dispMini.setText("");
}
}
}
Operate.java file
public class operate {
private double dispValue;
private double tempValue; //used while waiting the value input
private String tempOperator; //used while waiting the operator enter
public static final String add = "+";
public static final String sub = "-";
public static final String mul = "X";
public static final String div = "/";
public static final String clr = "AC" ;
public static final String mod = "%" ;
public static final String squareroot = "√";
public static final String squared = "x²";
public static final String cube = "x³";
public static final String over = "1/x";
public static final String toogle = "+/-";
// constructor
public operate() {
// initialize variables upon start
dispValue = 0;
tempValue = 0;
tempOperator = "";
}
public void setOperand(double operand) {
dispValue = operand;
}
public double getResult() {
return dispValue;
}
public String toString() {
return Double.toString(dispValue);
}
protected double performOperation(String operator) {
switch (operator){
case clr:
dispValue = 0;
tempOperator = "";
tempValue = 0;
break;
case squareroot:
dispValue = Math.sqrt(dispValue);
break;
case squared:
dispValue = dispValue * dispValue;
break;
case cube:
dispValue = dispValue * dispValue * dispValue;
break;
case over:
if (dispValue != 0) {
dispValue = 1 / dispValue;
}
break;
case toogle:
dispValue = -dispValue;
break;
default:
simpleOperation();
tempOperator = operator;
tempValue = dispValue;
break;
}
return dispValue;
}
protected void simpleOperation() {
switch (tempOperator){
case add:
dispValue = tempValue + dispValue;
break;
case sub:
dispValue = tempValue - dispValue;
break;
case mul:
dispValue = tempValue * dispValue;
break;
case div:
if (dispValue != 0) {
dispValue = tempValue / dispValue;
}
break;
case mod:
dispValue = tempValue % dispValue;
break;
}
}
}
