Question

有人能告诉我这里的nullpointerexception是什么？它说它在第49行，＆＃34; cigstxt = currentUser.get（＆＃34; inADay＆＃34;）。toString（）;＆＃34;。我不知道第49行怎么可能是nullpointer但是第50行不能。

public class Welcome extends RegisterInformationActivity {

Button logout;
String cigstxt;
String moneysavedtxt;
String notsmokedtxt;
String timesavedtxt;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.welcome);

    TextView cigs = (TextView)findViewById(R.id.days);
    TextView moneysaved = (TextView)findViewById(R.id.moneysaved);
    TextView timesaved = (TextView)findViewById(R.id.timesaved);
    TextView notsmoked = (TextView)findViewById(R.id.notsmoked);

    final ParseUser currentUser = ParseUser.getCurrentUser();

    String struser = currentUser.getUsername().toString();

    TextView txtuser = (TextView)findViewById(R.id.textView);

    txtuser.setText(struser);

     cigstxt = currentUser.get("inADay").toString();
     moneysavedtxt = currentUser.get("days").toString();
     notsmokedtxt = currentUser.get("inABox").toString();
     timesavedtxt = currentUser.get("price").toString();

    cigs.setText(String.valueOf(cigstxt));
    moneysaved.setText(String.valueOf(moneysavedtxt));
    timesaved.setText(String.valueOf(timesavedtxt));
    notsmoked.setText(String.valueOf(notsmokedtxt));

    logout = (Button)findViewById(R.id.btnlogout);

    logout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            ParseUser.logOut();
            finish();
        }
    });
}}

logcat的：

04-28 21:30:48.196  20869-20869/com.lacher.quitsmoking_doitnow E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.lacher.quitsmoking_doitnow, PID: 20869
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lacher.quitsmoking_doitnow/com.lacher.quitsmoking_doitnow.Welcome}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2224)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2283)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5153)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:796)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:612)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.lacher.quitsmoking_doitnow.Welcome.onCreate(Welcome.java:49)
            at android.app.Activity.performCreate(Activity.java:5312)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2181)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2283)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1205)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5153)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:796)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:612)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

这是一个parse.com数据库的问题，我搞砸了（删除了最后一个用户名）。代码一直很好。现在它完美无缺！

java.lang.NullPointerException Parse.com

1 个答案: