This example is a simple loan calculator application which shows monthly payment and total loan of the values entered.
Algorithm:
1.) Create a new project by File-> New -> Android Project name it LoanCalculator.
2.) Write following into main.xml:
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| <?xml version="1.0" encoding="utf-8"?><TableLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:stretchColumns="1" android:shrinkColumns="1"> <TableRow> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/loan_amount_prompt" android:gravity="right"/> <EditText android:id="@+id/loan_amount" android:inputType="numberDecimal" android:layout_height="wrap_content"> <requestFocus></requestFocus> </EditText> </TableRow> <TableRow> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/interest_rate_prompt" android:gravity="right"/> <EditText android:id="@+id/interest_rate" android:inputType="numberDecimal" android:layout_height="wrap_content"/> </TableRow> <TableRow> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/loan_period_prompt" android:gravity="right"/> <EditText android:id="@+id/loan_period" android:inputType="number" android:layout_height="wrap_content"/> </TableRow> <TableRow> <Button android:text="@string/loan_button_text" android:layout_span="2" android:layout_width="match_parent" android:layout_height="wrap_content" android:onClick="showLoanPayments"/> </TableRow> <TableRow android:layout_marginTop="20dp"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/monthly_payment_prompt" android:gravity="right"/> <TextView android:id="@+id/monthly_payment_result" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#ff0000" android:gravity="left"/> </TableRow> <TableRow> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/total_payments_prompt" android:gravity="right"/> <TextView android:id="@+id/total_payments_result" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#ff0000" android:gravity="left"/> </TableRow></TableLayout> |
3.) Write following into values/strings.xml:
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| <?xml version="1.0" encoding="utf-8"?><resources> <string name="app_name">LoanCalculator</string> <string name="hello_world">Hello world!</string> <string name="menu_settings">Settings</string> <string name="loan_amount_prompt">Loan amount:  </string> <string name="interest_rate_prompt">Interest rate:  </string> <string name="loan_period_prompt">Months:  </string> <string name="loan_button_text">Calculate Payments</string> <string name="monthly_payment_prompt">Monthly payment:  </string> <string name="total_payments_prompt">Total payments:  </string></resources> |
4.) Run for output.
Steps:
1.) Create a project named LoanCalculator and set the information as stated in the image.
Build Target: Android 4.0
Application Name: LoanCalculator
Package Name: com. example. LoanCalculator
Activity Name: LoanCalculatorActivity
Min SDK Version: 2.2
Application Name: LoanCalculator
Package Name: com. example. LoanCalculator
Activity Name: LoanCalculatorActivity
Min SDK Version: 2.2
2.) Open LoanCalculatorActivity.java file and write following code there:
package com.example.loancalculator;
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| import java.text.DecimalFormat;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.EditText;import android.widget.TextView;public class LoanCalculatorActivity extends Activity { private EditText mLoanAmount, mInterestRate, mLoanPeriod; private TextView mMontlyPaymentResult, mTotalPaymentsResult; /** Initializes the app when it is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mLoanAmount = (EditText)findViewById(R.id.loan_amount); mInterestRate = (EditText)findViewById(R.id.interest_rate); mLoanPeriod = (EditText)findViewById(R.id.loan_period); mMontlyPaymentResult = (TextView)findViewById(R.id.monthly_payment_result); mTotalPaymentsResult = (TextView)findViewById(R.id.total_payments_result); } public void showLoanPayments(View clickedButton) { double loanAmount = Integer.parseInt(mLoanAmount.getText().toString()); double interestRate = (Integer.parseInt(mInterestRate.getText().toString())); double loanPeriod = Integer.parseInt(mLoanPeriod.getText().toString()); double r = interestRate/1200; double r1 = Math.pow(r+1,loanPeriod); double monthlyPayment = (double) ((r+(r/(r1-1))) * loanAmount); double totalPayment = monthlyPayment * loanPeriod; mMontlyPaymentResult.setText(new DecimalFormat("##.##").format(monthlyPayment)); mTotalPaymentsResult.setText(new DecimalFormat("##.##").format(totalPayment)); }} |
3.) Compile and build the project.
Output
