title: Using DecimalFormat with Android Development
body: <p>I have looked at ways to solve this I am still very new to java and just looking into it and am kind of diving head first into it and ran into a problem. The problem I am having is that I want to change the number of Decimal places that is output by this "Tip Calculator" I am making and I also want it to format in currency using the $ symbol. My code is below I am using </p>
  
  <pre><code>public class TipCalculatorActivity extends Activity {
  
        DecimalFormat money = new DecimalFormat("$0.00");
        EditText costofmeal, tippercent;
        TextView tiptotal, totalbill; 
        Button calctipbtn;
        BigDecimal costNum, percentNum, billNum;
  
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
  
              super.onCreate(savedInstanceState);
              setContentView(R.layout.main);
              calctipbtn = (Button) findViewById(R.id.calctipbtn);
              costofmeal = (EditText) findViewById(R.id.CostofMeal); 
              tippercent = (EditText) findViewById(R.id.PercentTipText);
              tiptotal = (TextView) findViewById(R.id.tiptotal);       
              totalbill = (TextView) findViewById(R.id.totalbill);   
              calctipbtn.setOnClickListener(new View.OnClickListener() {
              public void onClick(View v) {
                  // TODO Auto-generated method stub
                  costNum = new BigDecimal(costofmeal.getText().toString());
                  percentNum = new BigDecimal(tippercent.getText().toString());
  
                  tiptotal.setText(costNum.multiply(percentNum).toString());
                  System.out.println(money.format(tiptotal));
  
                  costNum = new BigDecimal(costofmeal.getText().toString());
                  billNum = new BigDecimal(tiptotal.getText().toString());
  
  
                  totalbill.setText(costNum.add(billNum).toString());
                  System.out.println(money.format(totalbill));
              }
            });   
       }
  } 
  </code></pre>
  
  <p>My method of thinking was basically that I could have the output of the equation and then I could use the <code>money.format</code> and call the <code>textview</code> that I used and it would format it to the <code>DecimalFormat</code> that I had. Instead now the app force closes when I hit the calculate button the log errors I get are </p>
  
  <pre><code>06-04 21:32:57.242: D/AndroidRuntime(1905): Shutting down VM
  
  06-04 21:32:57.242: W/dalvikvm(1905): threadid=1: thread exiting with uncaught exception    (group=0x40015578)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905): FATAL EXCEPTION: main
  
  06-04 21:32:57.257: E/AndroidRuntime(1905): java.lang.IllegalArgumentException
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at java.text.NumberFormat.format(NumberFormat.java:308)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at 
  java.text.DecimalFormat.format(DecimalFormat.java:714)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at java.text.Format.format(Format.java:93)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at com.verge.tipcalc.TipCalculatorActivity$1.onClick(TipCalculatorActivity.java:50)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at android.view.View.performClick(View.java:2537)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at android.view.View$PerformClick.run(View.java:9157)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at 
  android.os.Handler.handleCallback(Handler.java:587)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at android.os.Handler.dispatchMessage(Handler.java:92)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at android.os.Looper.loop(Looper.java:130)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at android.app.ActivityThread.main(ActivityThread.java:3687)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at java.lang.reflect.Method.invokeNative(Native Method)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at java.lang.reflect.Method.invoke(Method.java:507)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at 
  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
  
  06-04 21:32:57.257: E/AndroidRuntime(1905):     at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>All I want to do is round the <code>totalbill</code> and the <code>tiptotal</code> to 2 decimal places and have it formatted in currency I have tried like 3-4 methods I looked up and none of them have been successful.</p>