Android Open Source - SimpleTipCalculator Tip Activity

• Back to Calculator/class  ↑

From Project

Back to project page SimpleTipCalculator.

License

The source code is released under:

MIT License

Java Source Code

package com.nickrasband.tipcalculator;
//from  w  w w  . ja v  a  2 s. c o m
import java.text.NumberFormat;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Gravity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class TipActivity extends Activity {
  
  private EditText etAmount;
  private TextView tvTipAmount;
  private TextView tvTotalAmount;
  private Button lastButtonPressed;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_tip);
    
    lastButtonPressed = null;
    
    // Get references to all of the form elements.
    etAmount = (EditText)findViewById(R.id.etAmount);
    tvTipAmount = (TextView)findViewById(R.id.tvTipAmount);
    tvTotalAmount = (TextView)findViewById(R.id.tvTotalAmount);  
    
    // Add a text changed listener to the transaction amount field to automatically update the tip/total.
    etAmount.addTextChangedListener(new TextWatcher() {
      @Override
      public void afterTextChanged(Editable s) {
        String amount = s.toString();
        if (amount == null || amount.isEmpty())
        {
          clearLabels();
        }
        
        if (lastButtonPressed == null) return;
        
        calculateTip(lastButtonPressed);
      }

      @Override
      public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        return;
      }

      @Override
      public void onTextChanged(CharSequence s, int start, int before, int count) {
        return;
      }
    });
    
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.tip, menu);
    return true;
  }
  
  // This method to any of the tip buttons being clicked.
  // It then determines which one was clicked and calculates the tip and total.
  public void calculateTip(View v) {
    lastButtonPressed = (Button)v;
    float tipPercent = 0.0f;
    switch(v.getId()) {
    case R.id.btnTenPercent:
      tipPercent = 0.1f;
      break;
    case R.id.btnFifteenPercent:
      tipPercent = 0.15f;
      break;
    case R.id.btnEighteenPercent:
      tipPercent = 0.18f;
      break;
    case R.id.btnTwentyPercent:
      tipPercent = 0.2f;
      break;
    }
    
    // Some simple validation. Make sure that the amount is not null or empty.
    String amount = etAmount.getText().toString();
    if (amount == null || amount.isEmpty())
    {
      // Show a toast to prompt the user to enter a transaction amount.
      Toast toast = Toast.makeText(this, R.string.empty_transaction_toaster, Toast.LENGTH_SHORT);
      toast.setGravity(Gravity.TOP | Gravity.CENTER, 0, 100);
      toast.show();
      
      clearLabels();
      
      return;
    }
    
    // Calculate and display the tip and total.
    float bill = Float.parseFloat(amount);
    float tip = bill * tipPercent;
    float total = bill + tip;
    tvTipAmount.setText(NumberFormat.getCurrencyInstance().format(tip) + "   (" + lastButtonPressed.getText() + ")");
    tvTotalAmount.setText(NumberFormat.getCurrencyInstance().format(total));
  }
  
  // Clear out the labels which show the tip and total.
  private void clearLabels() {
    tvTipAmount.setText(R.string.empty_amount);
    tvTotalAmount.setText(R.string.empty_amount);
  }

}

Java Source Code List

• Back to Calculator/class  ↑