我目前正在开发一个Android应用程序。我一开始没有任何问题，但是当我运行我的代码时，页面意外停止。首先，我运行mcpakej1.xml。然后在我点击提交按钮而不在编辑文本中输入任何值后，页面意外停止。当我看到logcat中的错误时，错误发生在其他页面。下面是代码。
mcpakej1.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="150dp"
android:layout_height="40dp"
android:text="Package A \n"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/textView50"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Number of guest(s)"/>
<EditText
android:id="@+id/guest"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:inputType="number"
android:textStyle="bold"
android:textAppearance="?android:attr/textAppearanceMedium"
android:hint="Maximum : 10000" >
<requestFocus />
</EditText>
</LinearLayout>
</ScrollView>
<ImageButton
android:id="@+id/homebtn"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignTop="@+id/homebtn"
android:layout_toLeftOf="@+id/homebtn"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:background="@drawable/homebtn"
android:onClick="goHome" />
<ImageButton
android:id="@+id/gobutton"
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_alignTop="@+id/homebtn"
android:layout_toRightOf="@+id/homebtn"
android:layout_alignParentBottom="true"
android:background="@drawable/gobutton"
android:onClick="goReceipt"/>
<ImageButton
android:id="@+id/backbutton"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignTop="@+id/homebtn"
android:layout_alignParentBottom="true"
android:layout_toLeftOf="@+id/homebtn"
android:background="@drawable/backbutton"
android:onClick="goPackage"
android:gravity="right"/>
</RelativeLayout>
这是mcpakej1.java
public class mcpakej1 extends Activity
{
private EditText passEditText;
CheckBox nsPutih,nsBeriyani,nsMinyak,aymKurma,aymLemak,aymKari,aymRendang,aymMerah,
prtAsam, dggTomato, dggSinggang, dggMerah,kerabuTaugeh, pindangKacang,jelatah,dalcaSayur,papadom,
kariIkan,ikanMasin, sirapAis, oren,tehTarik,agarAgar, buburKacang,kuih;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.mcpakej1);
passEditText = (EditText) findViewById(R.id.guest);
nsPutih = (CheckBox) findViewById(R.id.pakejA1);
nsBeriyani = (CheckBox) findViewById(R.id.pakejA2);
nsMinyak = (CheckBox) findViewById(R.id.pakejA3);
aymKurma = (CheckBox) findViewById(R.id.pakejA4);
aymLemak = (CheckBox) findViewById(R.id.pakejA5);
aymKari = (CheckBox) findViewById(R.id.pakejA6);
aymRendang = (CheckBox) findViewById(R.id.pakejA7);
aymMerah = (CheckBox) findViewById(R.id.pakejA8);
prtAsam = (CheckBox) findViewById(R.id.pakejA9);
dggTomato = (CheckBox) findViewById(R.id.pakejA10);
dggSinggang = (CheckBox) findViewById(R.id.pakejA11);
dggMerah = (CheckBox) findViewById(R.id.pakejA12);
kerabuTaugeh = (CheckBox) findViewById(R.id.pakejA13);
pindangKacang = (CheckBox) findViewById(R.id.pakejA14);
jelatah = (CheckBox) findViewById(R.id.pakejA15);
dalcaSayur = (CheckBox) findViewById(R.id.pakejA16);
papadom = (CheckBox) findViewById(R.id.pakejA17);
kariIkan = (CheckBox) findViewById(R.id.pakejA18);
ikanMasin = (CheckBox) findViewById(R.id.pakejA19);
sirapAis = (CheckBox) findViewById(R.id.pakejA20);
oren = (CheckBox) findViewById(R.id.pakejA21);
tehTarik = (CheckBox) findViewById(R.id.pakejA22);
agarAgar = (CheckBox) findViewById(R.id.pakejA23);
buburKacang = (CheckBox) findViewById(R.id.pakejA24);
kuih = (CheckBox) findViewById(R.id.pakejA25);
}
public void goHome(View v){
{
Intent intent = new Intent(v.getContext(), MainActivity.class);
startActivityForResult(intent,0);}
}
public void goReceipt(View v)
{
Intent intent = new Intent(v.getContext(), doReceipt.class);
intent.putExtra("nsBeriyani", nsBeriyani.isChecked());
intent.putExtra("nsPutih", nsPutih.isChecked());
intent.putExtra("nsMinyak", nsMinyak.isChecked());
intent.putExtra("aymKurma", aymKurma.isChecked());
intent.putExtra("aymKari", aymKari.isChecked());
intent.putExtra("aymRendang", aymRendang.isChecked());
intent.putExtra("aymMerah", aymMerah.isChecked());
intent.putExtra("prtAsam", prtAsam.isChecked());
intent.putExtra("dggTomato", dggTomato.isChecked());
intent.putExtra("dggSinggang", dggSinggang.isChecked());
intent.putExtra("dggMerah", dggMerah.isChecked());
intent.putExtra("kerabuTaugeh", kerabuTaugeh.isChecked());
intent.putExtra("pindangKacang", pindangKacang.isChecked());
intent.putExtra("jelatah", jelatah.isChecked());
intent.putExtra("dalcaSayur", dalcaSayur.isChecked());
intent.putExtra("papadom", papadom.isChecked());
intent.putExtra("kariIkan", kariIkan.isChecked());
intent.putExtra("ikanMasin", ikanMasin.isChecked());
intent.putExtra("sirapAis", sirapAis.isChecked());
intent.putExtra("oren", oren.isChecked());
intent.putExtra("tehTarik", tehTarik.isChecked());
intent.putExtra("agarAgar", agarAgar.isChecked());
intent.putExtra("buburKacang", buburKacang.isChecked());
intent.putExtra("kuih", kuih.isChecked());
findViewById(R.id.gobutton).setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View arg0)
{ final String pass = passEditText.getText().toString();
if (!isValidPassword(pass))
{
passEditText.setError("Invalid Number");
}
}
});
startActivityForResult(intent,0);
}
public void goPackage(View v){
{
Intent intent = new Intent(v.getContext(), PackageSelect.class);
startActivityForResult(intent,0);}
}
// validating password with retype password
private boolean isValidPassword(String pass)
{
if (pass != null && pass.length() <= 10000) {
return true;
}
return false;
}}
这是我点击提交按钮后在logcat中收到的错误。
11-22 10:38:04.434: E/AndroidRuntime(1173): at dalvik.system.NativeStart.main(Native Method)
11-22 10:38:04.434: E/AndroidRuntime(1173): Caused by: java.lang.NullPointerException
11-22 10:38:04.434: E/AndroidRuntime(1173): at com.example.mobilecatering.doReceipt.onCreate(doReceipt.java:398)
11-22 10:38:04.434: E/AndroidRuntime(1173): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-22 10:38:04.434: E/AndroidRuntime(1173): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11-22 10:38:04.434: E/AndroidRuntime(1173): ... 11 more
11-22 10:38:06.294: I/Process(1173): Sending signal. PID: 1173 SIG: 9
这是错误状态为doReceipt.java的页面
public class doReceipt extends Activity
{
boolean nsPutih, nsBeriyani,nsMinyak,aymKurma,aymLemak,aymKari,aymRendang,aymMerah,
prtAsam, dggTomato, dggSinggang, dggMerah,kerabuTaugeh, pindangKacang,jelatah,dalcaSayur,papadom,
kariIkan,ikanMasin, sirapAis, oren,tehTarik,agarAgar, buburKacang,kuih, price;
TextView tvOutput1,tvOutput2, tvOutput3, tvOutput4, tvOutput5, tvOutput6, tvOutput7, tvOutput8, tvOutput9, tvOutput10,
tvOutput11, tvOutput12, tvOutput13, tvOutput14, tvOutput15, tvOutput16, tvOutput17, tvOutput18, tvOutput19, tvOutput20,
tvOutput21, tvOutput22, tvOutput23, tvOutput24, tvOutput25, tvOutput26, tvOutput27, tvOutput28;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.receipt);
Bundle extras = getIntent().getExtras();
if (extras == null) {
return;
}
// assign the values to string-arguments
String phone = extras.getString("phone");
TextView phoneText = (TextView) findViewById(R.id.textView27);
phoneText.setText(phone);
tvOutput1 = (TextView) findViewById(R.id.textView1);
tvOutput2 = (TextView) findViewById(R.id.textView2);
tvOutput3 = (TextView) findViewById(R.id.textView3);
tvOutput4 = (TextView) findViewById(R.id.textView4);
tvOutput5 = (TextView) findViewById(R.id.textView5);
tvOutput6 = (TextView) findViewById(R.id.textView6);
tvOutput7 = (TextView) findViewById(R.id.textView7);
tvOutput8 = (TextView) findViewById(R.id.textView8);
tvOutput9 = (TextView) findViewById(R.id.textView9);
tvOutput10 = (TextView) findViewById(R.id.textView10);
tvOutput11 = (TextView) findViewById(R.id.textView11);
tvOutput12 = (TextView) findViewById(R.id.textView12);
tvOutput13 = (TextView) findViewById(R.id.textView13);
tvOutput14 = (TextView) findViewById(R.id.textView14);
tvOutput15 = (TextView) findViewById(R.id.textView15);
tvOutput16 = (TextView) findViewById(R.id.textView16);
tvOutput17 = (TextView) findViewById(R.id.textView17);
tvOutput18 = (TextView) findViewById(R.id.textView18);
tvOutput19 = (TextView) findViewById(R.id.textView19);
tvOutput20 = (TextView) findViewById(R.id.textView20);
tvOutput21 = (TextView) findViewById(R.id.textView21);
tvOutput22 = (TextView) findViewById(R.id.textView22);
tvOutput23 = (TextView) findViewById(R.id.textView23);
tvOutput24 = (TextView) findViewById(R.id.textView24);
tvOutput25 = (TextView) findViewById(R.id.textView25);
tvOutput26 = (TextView) findViewById(R.id.textView26);
tvOutput27 = (TextView) findViewById(R.id.textView27);
tvOutput28 = (TextView) findViewById(R.id.textView28);
Bundle data = this.getIntent().getExtras();
nsPutih=data.getBoolean("nsPutih");
nsBeriyani=data.getBoolean("nsBeriyani");
nsMinyak=data.getBoolean("nsMinyak");
aymKurma=data.getBoolean("aymKurma");
aymLemak=data.getBoolean("aymLemak");
aymKari=data.getBoolean("aymKari");
aymRendang=data.getBoolean("aymRendang");
aymMerah=data.getBoolean("aymMerah");
prtAsam=data.getBoolean("prtAsam");
dggTomato=data.getBoolean("dggTomato");
dggSinggang=data.getBoolean("dggSinggang");
dggMerah=data.getBoolean("dggMerah");
kerabuTaugeh=data.getBoolean("kerabuTaugeh");
pindangKacang=data.getBoolean("pindangKacang");
jelatah=data.getBoolean("jelatah");
dalcaSayur=data.getBoolean("dalcaSayur");
papadom=data.getBoolean("papadom");
kariIkan=data.getBoolean("kariIkan");
ikanMasin=data.getBoolean("ikanMasin");
sirapAis=data.getBoolean("sirapAis");
oren=data.getBoolean("oren");
tehTarik=data.getBoolean("tehTarik");
agarAgar=data.getBoolean("agarAgar");
buburKacang=data.getBoolean("buburKacang");
kuih=data.getBoolean("kuih");
price=data.getBoolean("price");
double price = 0;
//StringBuffer stringBuffer = new StringBuffer();
if(nsPutih==true)
{
tvOutput1.setText("Nasi Putih - RM 1.00");
tvOutput1.setVisibility(View.VISIBLE);
price+=1;
}
else
{
tvOutput1.setVisibility(View.GONE);
}
if (nsBeriyani==true)
{
tvOutput2.setText("Nasi Beriyani - RM 2.00");
tvOutput2.setVisibility(View.VISIBLE);
price+=2.0;
}
else
{
tvOutput2.setVisibility(View.GONE);
}
if (nsMinyak==true)
{
tvOutput3.setText("Nasi Minyak - RM 1.50");
tvOutput3.setVisibility(View.VISIBLE);
price+=1.5;
}
else
{
tvOutput3.setVisibility(View.GONE);
}
if(aymKurma==true)
{
tvOutput4.setText("Ayam Masak Kurma - RM 2.00");
tvOutput4.setVisibility(View.VISIBLE);
price+=2;
}
else
{
tvOutput4.setVisibility(View.GONE);
}
if (aymLemak==true)
{
tvOutput5.setText("Ayam Masak Lemak - RM 4.00");
tvOutput5.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput5.setVisibility(View.GONE);
}
if (aymKari==true)
{
tvOutput6.setText("Ayam Masak Kari - RM 4.00");
tvOutput6.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput6.setVisibility(View.GONE);
}
if (aymRendang==true)
{
tvOutput7.setText("Ayam Masak Rendang - RM 4.00");
tvOutput7.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput7.setVisibility(View.GONE);
}
if (aymMerah==true)
{
tvOutput8.setText("Ayam Masak Merah - RM 4.00");
tvOutput8.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput8.setVisibility(View.GONE);
}
if (prtAsam==true)
{
tvOutput9.setText("Perut Air Asam - RM 3.00");
tvOutput9.setVisibility(View.VISIBLE);
price+=3;
}
else
{
tvOutput9.setVisibility(View.GONE);
}
if (dggTomato==true)
{
tvOutput10.setText("Daging Masak Tomato - RM 4.00");
tvOutput10.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput10.setVisibility(View.GONE);
}
if (dggSinggang==true)
{
tvOutput11.setText("Daging Masak Singgang - RM 4.00");
tvOutput11.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput11.setVisibility(View.GONE);
}
if (dggMerah==true)
{
tvOutput12.setText("Daging Masak Merah - RM 4.00");
tvOutput12.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput12.setVisibility(View.GONE);
}
if (kerabuTaugeh==true)
{
tvOutput13.setText("Kerabu Taugeh - RM 1.50");
tvOutput13.setVisibility(View.VISIBLE);
price+=1.5;
}
else
{
tvOutput13.setVisibility(View.GONE);
}
if (pindangKacang==true)
{
tvOutput14.setText("Pindang Kacang - RM 1.00");
tvOutput14.setVisibility(View.VISIBLE);
price+=1;
}
else
{
tvOutput14.setVisibility(View.GONE);
}
if (jelatah==true)
{
tvOutput15.setText("Jelatah - RM 2.00");
tvOutput15.setVisibility(View.VISIBLE);
price+=2;
}
else
{
tvOutput15.setVisibility(View.GONE);
}
if (dalcaSayur==true)
{
tvOutput16.setText("Dalca Sayur - RM 1.50");
tvOutput16.setVisibility(View.VISIBLE);
price+=1.5;
}
else
{
tvOutput16.setVisibility(View.GONE);
}
if (papadom==true)
{
tvOutput17.setText("Papadom - RM 0.50");
tvOutput17.setVisibility(View.VISIBLE);
price+=0.5;
}
else
{
tvOutput17.setVisibility(View.GONE);
}
if (kariIkan==true)
{
tvOutput18.setText("Kari Ikan - RM 1.50");
tvOutput18.setVisibility(View.VISIBLE);
price+=1.5;
}
else
{
tvOutput18.setVisibility(View.GONE);
}
if (ikanMasin==true)
{
tvOutput19.setText("Kari Ikan Masin - RM 4.00");
tvOutput19.setVisibility(View.VISIBLE);
price+=4;
}
else
{
tvOutput19.setVisibility(View.GONE);
}
if (sirapAis==true)
{
tvOutput20.setText("Minuman Sejuk - RM 1.50");
tvOutput20.setVisibility(View.VISIBLE);
price+=1.5;
}
else
{
tvOutput20.setVisibility(View.GONE);
}
if (oren==true)
{
tvOutput21.setText("Jus Buah - RM 2.00");
tvOutput21.setVisibility(View.VISIBLE);
price+=2;
}
else
{
tvOutput21.setVisibility(View.GONE);
}
if (tehTarik==true)
{
tvOutput22.setText("Minuman Panas - RM 1.00");
tvOutput22.setVisibility(View.VISIBLE);
price+=1.0;
}
else
{
tvOutput22.setVisibility(View.GONE);
}
if (agarAgar==true)
{
tvOutput23.setText("Agar Agar - RM 1.00");
tvOutput23.setVisibility(View.VISIBLE);
price+=1;
}
else
{
tvOutput23.setVisibility(View.GONE);
}
if (buburKacang==true)
{
tvOutput24.setText("Bubur Kacang - RM 2.50");
tvOutput24.setVisibility(View.VISIBLE);
price+=2.5;
}
else
{
tvOutput24.setVisibility(View.GONE);
}
if (kuih==true)
{
tvOutput25.setText("Kuih Muih - RM 1.00");
tvOutput25.setVisibility(View.VISIBLE);
price+=1;
}
else
{
tvOutput25.setVisibility(View.GONE);
}
Log.e("MENU PAKEJ A","Total Price: RM "+ price);
String stringdouble = Double.toString(price);
tvOutput26.setText("\n\n Price Per Person : RM "+ stringdouble);
double e1 = Double.parseDouble(stringdouble.toString());
double e2 = Double.parseDouble(phone.toString()); <!-- the error line -->
tvOutput28.setText("Total price for all guest(s) : RM " + String.valueOf(e1*e2));
}
public void goHome(View v){
{
Intent intent = new Intent(v.getContext(), MainActivity.class);
startActivityForResult(intent,0);}
}
public void goPackage(View v){
{
Intent intent = new Intent(v.getContext(), mcpakej1.class);
startActivityForResult(intent,0);}
}
public void goOrder(View v){
{
Intent intent = new Intent(v.getContext(), OrderProcess.class);
startActivityForResult(intent,0);}
}
}
答案 0 :(得分：0)
尝试这样的事情：
tvOutput4.setText("Multiplication Result is: " +String.valueOf(e1*e2));
tvOutput4.setVisibility(View.VISIBLE);