关于Android的一个程序问题，货币转换

============问题描述============

这是界面

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <TextView

	    android:id="@+id/text2"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content"

	    android:text="Convert this amount:">

	</TextView>

	<EditText

	    android:id="@+id/edit1"

	    android:layout_width="fill_parent"

	    android:layout_height="wrap_content"

	    android:inputType="number">

	</EditText>

	<TextView

	    android:id="@+id/text3"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content"

	    android:text="From:">

	</TextView>

	<Spinner

	    android:id="@+id/spinner1"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content">"

	</Spinner>

	<TextView

	    android:id="@+id/text4"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content"

	    android:text="To:">

	</TextView>

	<Spinner

	    android:id="@+id/spinner2"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content">

	</Spinner>

	<Button

	    android:id="@+id/button3"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content"

	    android:text="Convert">"

	</Button>

	<TextView

	    android:id="@+id/text5"

	    android:layout_width="match_parent"

	    android:layout_height="wrap_content"

	    android:textSize="25px"

	    android:gravity="center">

	</TextView>

</LinearLayout>

这是界面的XML

package com.exercise2;



import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.inputmethod.EditorInfo;

import android.widget.*;



public class Currency extends Activity

{

	private EditText cedit;

	private Spinner cfrom;

	private Spinner cto;

	private Button cconvert;

	private TextView ctext;

	private Toast toast;

	private ArrayAdapter<String> madapter1;

	private ArrayAdapter<String> madapter2;

	private String[] cdatafrom=

		{

			"-Please Select-",

			"CNY","USD","GBP","EUR","JPY","HKD"

		};

	private String[] cdatato=

		{

			"-Please Select-",

			"CNY","USD","GBP","EUR","JPY","HKD"

		};

	

	protected void onCreate(Bundle savedInstanceState) 

	{

		super.onCreate(savedInstanceState);

		setContentView(R.layout.currencyconverter);

		

		cedit=(EditText)findViewById(R.id.edit2);

		cconvert=(Button)findViewById(R.id.button3);

		ctext=(TextView)findViewById(R.id.text5);

		

		cfrom=(Spinner)findViewById(R.id.spinner1);

		madapter1=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,cdatafrom);

		madapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

		cfrom.setAdapter(madapter1);

		

		cto=(Spinner)findViewById(R.id.spinner2);

		madapter2=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,cdatato);

		madapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

		cto.setAdapter(madapter2);

		

		//cedit.setInputType(EditorInfo.TYPE_CLASS_PHONE); 

		

		cconvert.setOnClickListener(new OnClickListener()

		{

			public void onClick(View v) 

			{

				// TODO Auto-generated method stub

				

				String str=cedit.getText().toString();

				double curr=Double.parseDouble(str);

				

				while(!str.equalsIgnoreCase(""))

				{

					String from=cfrom.getSelectedItem().toString();

					String to=cto.getSelectedItem().toString();

					

					if(cfrom.getSelectedItem().toString().equalsIgnoreCase(cto.getSelectedItem().toString()))

					{

						ctext.setText("ssss");

						//ctext.setText(str+" "+cfrom.getSelectedItem().toString());

					}

					else

					{

						if(cfrom.getSelectedItem().toString().equalsIgnoreCase("CNY"))

						{

							if(cto.getSelectedItem().toString().equalsIgnoreCase("USD"))

							{

								double curr1=curr*0.1631;

								ctext.setText(curr1+" USD");

							}

							if(cto.getSelectedItem().toString().equalsIgnoreCase("GBP"))

							{

								double curr1=curr*0.1008;

								ctext.setText(curr1+" GBP");

							}

							if(cto.getSelectedItem().toString().equalsIgnoreCase("EUR"))

							{

								double curr1=curr*0.1283;

								ctext.setText(curr1+" EUR");

							}

							if(cto.getSelectedItem().toString().equalsIgnoreCase("JPY"))

							{

								double curr1=curr*17.5914;

								ctext.setText(curr1+" JPY");

							}

							if(cto.getSelectedItem().toString().equalsIgnoreCase("HKD"))

							{

								double curr1=curr*1.2653;

								ctext.setText(curr1+" HKD");

							}

						}

						while(from=="USD")

						{

							if(to=="CNY")

							{

								double curr1=curr*6.1298;

								ctext.setText(curr1+" "+to);

							}

							if(to=="GBP")

							{

								double curr1=curr*0.6179;

								ctext.setText(curr1+" "+to);

							}

							if(to=="EUR")

							{

								double curr1=curr*0.7863;

								ctext.setText(curr1+" "+to);

							}

							if(to=="JPY")

							{

								double curr1=curr*107.8320;

								ctext.setText(curr1+" "+to);

							}

							if(to=="HKD")

							{

								double curr1=curr*7.7561;

								ctext.setText(curr1+" "+to);

							}

						}

						while(from=="GBP")

						{

							if(to=="CNY")

							{

								double curr1=curr*9.9204;

								ctext.setText(curr1+" "+to);

							}

							if(to=="USD")

							{

								double curr1=curr*1.6184;

								ctext.setText(curr1+" "+to);

							}

							if(to=="EUR")

							{

								double curr1=curr*1.2725;

								ctext.setText(curr1+" "+to);

							}

							if(to=="JPY")

							{

								double curr1=curr*174.5137;

								ctext.setText(curr1+" "+to);

							}

							if(to=="HKD")

							{

								double curr1=curr*12.5524;

								ctext.setText(curr1+" "+to);

							}

						}

					}

				}

				while(str.equalsIgnoreCase(""))

				{

					toast=Toast.makeText(Currency.this, "Enter The Value", Toast.LENGTH_SHORT);

					toast.show();

				}

			}

		});

	}

}

这是部分代码
但是会有错，停止运行。。。
这是Logcat红色部分截图。
我自己想了很久，刚学水平有限啊。。
求大大帮忙看看

============解决方案1============

edit2在xml布局文件中没有定义，导致cedit对象为null

============解决方案2============

cedit=(EditText)findViewById(R.id.edit2);中R.id.edit2换成R.id.edit1就行了