用奇怪的NullPointerException建议
这是我的课。我有个问题。我正确地填写了所有的数据，当我制作Toast时，我得到了NullPointerExeption。我也不知道原因。我正在用EditTexts做所有的输入。有人能看出我做错了什么吗？
public class Wyslij extends Activity {
protected final int TIMEOUT_MILLISEC = 30;
EditText et_nazwa;
EditText et_nip;
EditText et_adres;
ImageButton ib_wyslij;
final TowarZamowienie tz = new TowarZamowienie();
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.wyslij);
et_nazwa = (EditText) findViewById(R.id.et_nazwa);
et_nip = (EditText) findViewById(R.id.et_nip);
et_adres = (EditText) findViewById(R.id.et_adres);
ib_wyslij = (ImageButton) findViewById(R.id.ib_wyslij);
String nazwa_firmy = et_nazwa.getText().toString();
String nip_firmowy = et_nip.getText().toString();
String adres_firmy = et_adres.getText().toString();
final Zamowienie zam = new Zamowienie();
if (nazwa_firmy != null && !nazwa_firmy.equalsIgnoreCase("")) {
zam.klient.setNazwa(et_nazwa.getText().toString());
}
if (nip_firmowy != null && !nip_firmowy.equalsIgnoreCase("")) {
zam.klient.setNip(et_nip.getText().toString());
}
if (adres_firmy != null && !adres_firmy.equalsIgnoreCase("")) {
zam.klient.setAdres(et_adres.getText().toString());
}
final String suma_zamowienia = podaj_sume(TowarZamowienie.towary_zamowione);
zam.setSuma(suma_zamowienia);
zam.setZam_id(MainActivity.nr_zamowienia);
MainActivity.nr_zamowienia++;
tz.setZam_id(zam.getZam_id());
final String[] s = new String[TowarZamowienie.towary_zamowione.size()];
for (int i = 0; i < TowarZamowienie.towary_zamowione.size(); i++) {
s[i] = TowarZamowienie.towary_zamowione.get(i).getTows_id();
}
ib_wyslij.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// new
Toast.makeText(getApplication(),
zam.klient.getNazwa()+ " "+zam.klient.getNip()+" "+zam.klient.getAdres().toString(), Toast.LENGTH_LONG)
.show();
}
});
}
private String podaj_sume(ArrayList<Towar> l) {
int suma = 0;
for (int i = 0; i < l.size(); i++) {
suma += l.get(i).Tow_ilosc * l.get(i).Tow_cena;
}
return String.valueOf(suma);
}
}我的LogCat错误：
02-11 23:08:59.546: W/dalvikvm(17234)：threadid=1:线程退出未明异常(group=0x40be71f8) 02-11 23:08:59.554: E/AndroidRuntime(17234)：致命异常:主02-11 23:08:59.554: E/AndroidRuntime(17234)：java.lang.NullPointerException 02-1123:08:59.554: E/AndroidRuntime(17234)：at group=0x40be71f8 02-1123:08:59.554: E/AndroidRuntime(17234)：在android.view.View.performClick(View.java:3558) 02-11 23:08:59.554: E/AndroidRuntime(17234)：在android.view.View$PerformClick.run(View.java:14152) 02-11 23:08:59.554: E/AndroidRuntime(17234)：在android.os.Handler.handleCallback(Handler.java:605) 02-11 23:08:59.554: E/AndroidRuntime(17234)：在android.os.Handler.dispatchMessage(Handler.java:92) 02-11 23:08:59.554: E/AndroidRuntime(17234)：android.os.Looper.loop(Looper.java:137) 02-11 23:08:59.554: E/AndroidRuntime(17234)：at android.app.ActivityThread.main(ActivityThread.java:4514) 02-11 23:08:59.554: 59.554: E/AndroidRuntime(17234)：at java.lang.reflect.Method.invokeNative(原生方法) 02-11 23:08:59.554: E/AndroidRuntime(17234)：在java.lang.reflect.Method.invoke(Method.java:511) 02-11 23:08:59.554: E/AndroidRuntime(17234)：at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) 02-11 23:08:59.554: E/AndroidRuntime(17234)：at com.android.internal.os.ZygoteInit.main(ZygoteInit.java：( 557) 02-11 23:08:59.554: E/AndroidRuntime(17234)：at dalvik.system.NativeStart.main(原生方法)
Zamowienie.class公共类Zamowienie {
public int id;
public int zam_id;
public String suma;
public Klient klient;
public Zamowienie(int id, String suma, Klient klient) {
super();
this.zam_id = id;
this.suma = suma;
this.klient = klient;
}
public Zamowienie() {
super();
}
public int getId() {
return id;
}
public int getZam_id() {
return zam_id;
}
public void setZam_id(int zam_id) {
this.zam_id = zam_id;
}
public void setId(int id) {
this.id = id;
}
public String getSuma() {
return suma;
}
public void setSuma(String suma) {
this.suma = suma;
}}
回答 3
Stack Overflow用户
发布于 2014-02-11 22:52:26
在onCreate()中，您可以这样做：
final Zamowienie zam = new Zamowienie();然后尝试访问zam.klient
但是您从来没有将zam.klient设置为任何东西，所以它是空的。
Stack Overflow用户
发布于 2014-02-11 22:43:00
尝试将其放入OnClick中：
Toast.makeText(Wyslij.this,
zam.klient.getNazwa()+ " "+zam.klient.getNip()+" "+zam.klient.getAdres().toString(), Toast.LENGTH_LONG)
.show();Stack Overflow用户
发布于 2014-02-11 22:52:25
您正在引用类klient变量Zamownienie。变量未设置。您正在调用Zamownienie的no-arg构造函数，这意味着klient被设置为null。
请考虑使用标准的Java命名约定，同时不要给类变量public范围。
HTH
https://stackoverflow.com/questions/21714119
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