I have just started using eclipse adt(android developer tool) and i am working on electricbill calculator app. The app interface looks like this: App interface
The user will input a value in previous consumption and current consumption then calculate(1st button) to get the total consumption. Then enter the rate and compute(2nd button, multiplies total consumption and rate) to get the electricbill.
My main activity contains onClickListeners for the buttons. The first part of the calculation works, but when i try to input a value and rate and compute it, the application crashes and i dont know where is the problem. Here is my code:
Calculate Button
public class MainActivity extends Activity {
EditText PrevConEdt, CurrConEdt, RateEdt;
TextView ConsumptionTv, ElectricBillTv;
Button CalculateBtn, ComputeBtn, ClearBtn, ClearBtn2;
Double rateDbl, cbillDbl, consumptionDbl, prevDbl, currentDbl;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PrevConEdt = (EditText) findViewById(R.id.txtPreviousConsumption);
CurrConEdt = (EditText) findViewById(R.id.txtCurrentConsumption);
RateEdt = (EditText) findViewById(R.id.txtEnterRate);
ConsumptionTv = (TextView) findViewById(R.id.txtConsumption);
ElectricBillTv = (TextView) findViewById(R.id.txtEbill);
CalculateBtn = (Button) findViewById(R.id.btnCalculate);
CalculateBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View Calculate) {
String prev, current, consumption;
prev = PrevConEdt.getText().toString();
current = CurrConEdt.getText().toString();
if(PrevConEdt.length() == 0){
Toast.makeText(MainActivity.this, "Consumption Required", Toast.LENGTH_LONG).show();
return;
}else if(CurrConEdt.length() == 0){
Toast.makeText(MainActivity.this, "Consumption Required", Toast.LENGTH_LONG).show();
return;
}else{
Double prevDbl, currentDbl, consumptionDbl;
prevDbl = Double.parseDouble(prev);
currentDbl = Double.parseDouble(current);
if(currentDbl < prevDbl){
//String msg = "Current should be greater than previous.";
//int duration = Toast.LENGTH_LONG;
//Toast.makeText(getBaseContext(), msg, duration).show();
//PrevConEdt.requestFocus();
CurrConEdt.setError("Current should be greater than previous.");
return;
}else{
consumptionDbl = currentDbl - prevDbl;
String consumptionStr = String.format("%.2f kWh", consumptionDbl);
ConsumptionTv.setText(consumptionStr);
}
}
}
});
Compute Button
ComputeBtn = (Button) findViewById(R.id.btnCompute);
ComputeBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View compute) {
String rate, consumption;
rate = RateEdt.getText().toString();
consumption = ConsumptionTv.getText().toString();
if(RateEdt.length() == 0){
RateEdt.setError("Rate is required.");
return;
}else{
Double rateDbl, cbillDbl, consumptionDbl;
rateDbl = Double.parseDouble(rate);
consumptionDbl = Double.parseDouble(consumption);
cbillDbl = consumptionDbl * rateDbl;
String billStr = String.format("Php %.2f", cbillDbl);
ElectricBillTv.setText(billStr);
}
}
});
