Are there any problems with my code?

Question

I'm having problems when running this. Instead of incrementing my tipAmount by .01 it goes from 0.10 to 0.11 to 0.01, but I have no idea why, and I can't seem to see anything wrong with the code or the onClick logic.

Code

package com.paulk.tipcalc;

import android.R.integer;
import android.support.v7.app.ActionBarActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;


public class TipCalc extends ActionBarActivity implements OnClickListener{


    public final static String BILL_WITHOUT_TIP = "BILL_WITHOUT_TIP";
    public final static String CURRENT_TIP = "CURRENT_TIP";
    public final static String TOTAL_BILL = "TOTAL_BILL";


    private double billBeforeTip;
    private double tipAmount;
    private double totalAmount;
    //private double billAfterTip = (billBeforeTip * tipAmount);

    EditText billBeforeTipET;
    EditText tipAmountET;
    EditText totalAmountET;

    Button increment;
    Button decrement;

    SeekBar tipSeekBar;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tip_calc);

        //if its a new session
        if(savedInstanceState == null){
            billBeforeTip = 0.0;
            tipAmount = 0.10;
            totalAmount = 0.0;

            //if its a saved session
        }else{
            billBeforeTip = savedInstanceState.getDouble(BILL_WITHOUT_TIP);
            tipAmount = savedInstanceState.getInt(CURRENT_TIP);
            totalAmount = savedInstanceState.getDouble(TOTAL_BILL);
        }

        //pulling through each of the text fields
        billBeforeTipET = (EditText) findViewById(R.id.BillEditText);
        tipAmountET = (EditText) findViewById(R.id.tipEditText);
        totalAmountET = (EditText) findViewById(R.id.totalEditText);

        tipSeekBar = (SeekBar) findViewById(R.id.changeTipSeekBar);

        increment = (Button) findViewById(R.id.incrementButton);
        decrement = (Button) findViewById(R.id.decrementButton);


        billBeforeTipET.addTextChangedListener(billBeforeTipListener);
        tipAmountET.addTextChangedListener(tipAmountListener);

        tipSeekBar.setOnSeekBarChangeListener(tipSeekBarChangeListener);

        increment.setOnClickListener(this);
        decrement.setOnClickListener(this);




    }
    private TextWatcher tipAmountListener = new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            try{
                tipAmount = (int) Double.parseDouble(s.toString());
            }catch(NumberFormatException e){
                tipAmount = 0.10;
            }
            updateTipandTotalAmount();
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable s) {
            // TODO Auto-generated method stub

        }
    };
    private TextWatcher billBeforeTipListener = new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            //making sure the correct format is input into the field
            try{
                billBeforeTip = Double.parseDouble(s.toString());
            }catch(NumberFormatException e){
                billBeforeTip = 0.0;
            }
            updateTipandTotalAmount();

        }


        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable s) {
            // TODO Auto-generated method stub

        }
    };


    private void updateTipandTotalAmount(){
        //converts the double value into a string value
        double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
        //how the total amount is calculated
        double totalAmount = billBeforeTip + (billBeforeTip * tipAmount);
        //formating the total amount
        totalAmountET.setText(String.format("%.02f", totalAmount));
    }
    protected void onSaveInstanceState(Bundle outState){
        super.onSaveInstanceState(outState);
        outState.putDouble(BILL_WITHOUT_TIP, billBeforeTip);
        outState.putDouble(CURRENT_TIP, tipAmount);
        outState.putDouble(TOTAL_BILL, totalAmount);

    }

    private OnSeekBarChangeListener tipSeekBarChangeListener =  new OnSeekBarChangeListener() {

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {
            tipAmount = (tipSeekBar.getProgress()*.01);

            tipAmountET.setText(String.format("%.02f", tipAmount));
        }
    };

    @Override
    public void onClick(View v) {
        switch(v.getId()){
        case R.id.incrementButton:

            tipAmount = tipAmount + 0.01;
            tipAmountET.setText(String.format("%.02f", tipAmount));
            break;

        case R.id.decrementButton:
            tipAmount = tipAmount - 0.01;
            tipAmountET.setText(String.format("%.02f", tipAmount));
            break;
        }


    }

    @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_calc, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.paulk.tipcalc.TipCalc" >

    <EditText
        android:id="@+id/BillEditText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/billTextView"
        android:layout_alignBottom="@+id/billTextView"
        android:layout_toEndOf="@+id/billTextView"
        android:layout_toRightOf="@+id/billTextView"
        android:ems="5"
        android:inputType="numberDecimal"
        android:text="@string/bill_edit_text" >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/billTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginStart="19dp"
        android:layout_marginLeft="19dp"
        android:layout_marginTop="20dp"
        android:text="@string/bill_text_view" />

    <TextView
        android:id="@+id/tipTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/BillEditText"
        android:layout_marginStart="34dp"
        android:layout_marginLeft="34dp"
        android:layout_toEndOf="@+id/billTextView"
        android:layout_toRightOf="@+id/BillEditText"
        android:text="@string/tip_text_view" />

    <Button
        android:id="@+id/incrementButton"
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:layout_alignEnd="@+id/tipEditText"
        android:layout_alignRight="@+id/tipEditText"
        android:layout_alignTop="@+id/tipTextView"
        android:onClick="increaaseTip"
        android:text="@string/increment"
        android:textSize="12sp" />

    <TextView
        android:id="@+id/totalTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/tipEditText"
        android:layout_toEndOf="@+id/billTextView"
        android:layout_toRightOf="@+id/billTextView"
        android:text="@string/total_text_view" />

    <EditText
        android:id="@+id/totalEditText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/totalTextView"
        android:layout_marginTop="19dp"
        android:layout_toStartOf="@+id/tipTextView"
        android:layout_toLeftOf="@+id/tipTextView"
        android:ems="5"
        android:inputType="numberDecimal"
        android:text="@string/total_edit_text" />

    <EditText
        android:id="@+id/tipEditText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/incrementButton"
        android:layout_marginTop="20dp"
        android:layout_toEndOf="@+id/billTextView"
        android:layout_toRightOf="@+id/tipTextView"
        android:ems="4"
        android:inputType="numberDecimal"
        android:text="@string/tip_edit_text" />

    <Button
        android:id="@+id/decrementButton"
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:layout_above="@+id/tipEditText"
        android:layout_marginEnd="12dp"
        android:layout_marginRight="12dp"
        android:layout_toLeftOf="@+id/incrementButton"
        android:layout_toStartOf="@+id/incrementButton"
        android:text="@string/decrement"
        android:textSize="12sp" 
        android:onClick="DecreaseTip"/>

    <SeekBar
        android:id="@+id/changeTipSeekBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/billTextView"
        android:layout_alignRight="@+id/BillEditText"
        android:layout_alignTop="@+id/tipEditText"
        android:progress="15" />

    <TextView
        android:id="@+id/changeTipTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/changeTipSeekBar"
        android:layout_alignLeft="@+id/changeTipSeekBar"
        android:text="@string/change_tip_text_view" />

</RelativeLayout>

Strings Class

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">TipCalc</string>
    <string name="action_settings">Settings</string>

    <string name="bill_text_view">Bill:</string>
    <string name="bill_edit_text"></string>

    <string name="decrement">-</string>
    <string name="increment">+</string>

    <string name="tip_text_view">Tip:</string>
    <string name="tip_edit_text">0.10</string>

    <string name="total_text_view">Total:</string>
    <string name="total_edit_text"></string>

    <string name="change_tip_text_view">Tip Changer</string>
</resources>

I just want it so it starts at 0.10 and increments and decrements by 0.01, however ive tried a few things and had no luck, any idea why?

Answer 1

Your problem might be that you are using getInt to load a double variable from the Bundle :

tipAmount = savedInstanceState.getInt(CURRENT_TIP);

This would return 0, since you are saving the value as double:

outState.putDouble(CURRENT_TIP, tipAmount);

Change it to:

tipAmount = savedInstanceState.getDouble (CURRENT_TIP);

public int getInt (String key)
Added in API level 1

Returns the value associated with the given key, or 0 if no mapping of the desired type exists for the given key

Another problem is in your onTextChanged method :

tipAmount = (int) Double.parseDouble(s.toString());

If the result of parsing the double < 1, tipAmount will be set to 0 by the casting to int.

Answer 2

In your textwatcher:

tipAmount = (int) Double.parseDouble(s.toString());

You're converting the tip amount to integer. (int)0.11 is 0 and adding 0.01 to it yields 0.01 again.