The following code shows how to create a Tip Calculator. It shows
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" >/*from w ww . j ava 2s. co m*/ <EditText android:id="@+id/mealprice" android:layout_width="fill_parent" android:layout_height="wrap_content" android:autoText="true" /> <Button android:id="@+id/calculate" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Calculate Tip" /> <TextView android:id="@+id/answer" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="" /> </LinearLayout>
Java code
package com.java2s.app; /* ww w. jav a2s . c o m*/ import android.app.Activity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import java.text.NumberFormat; public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final EditText mealpricefield = (EditText) findViewById(R.id.mealprice); final TextView answerfield = (TextView) findViewById(R.id.answer); final Button button = (Button) findViewById(R.id.calculate); button.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { try { // grab the meal price from the UI String mealprice = mealpricefield.getText().toString(); String answer = ""; if (mealprice.indexOf("$") == -1) { mealprice = "$" + mealprice; } float fmp = 0.0F; NumberFormat nf = java.text.NumberFormat.getCurrencyInstance(); fmp = nf.parse(mealprice).floatValue(); // 20% tip fmp *= 1.2; answer = "Full Price, Including 20% Tip: " + nf.format(fmp); answerfield.setText(answer); } catch (java.text.ParseException pe) { Log.i("java2s.com", "Parse exception caught"); answerfield.setText("Failed to parse amount?"); } catch (Exception e) { Log.e("java2s.com", "Failed to Calculate Tip:" + e.getMessage()); e.printStackTrace(); answerfield.setText(e.getMessage()); } } }); } }