java - Android Application Crashes when Creating custom class object -


i'm working on first android app , i'm having trouble creating object of class have programmed in java using oncreate function of activity. activity starts great when not instantiate object, when attempt create object app crashes when switching activity. oncreate function looks this...

    protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_entry);     // show button in action bar.     setupactionbar();     forcetable testtable = new forcetable();     double factor = testtable.returnvalue(forcetypes.newtons, forcetypes.newtons); }

forcetable class have programmed, code looks this...

public class forcetable {  private double[][] forcetable;  protected enum forcetypes {newtons(0), pounds(1), kilopond(2);     public int num;     private forcetypes(int num)     {         this.num = num;     } };  protected final class values{     private final static double zerozero = 1.00;     private final static double zeroone = 4.44872162;     private final static double zerotwo = 9.80665;     private final static double onezero = .224808943;     private final static double oneone = 1.00;     private final static double onetwo = 2.20462262;     private final static double twozero = .10197164;     private final static double twoone = .45359237;     private final static double twotwo = 1.00; }  public forcetable() {     this.maketable(); }  private void maketable() {     forcetable[0][0] = values.zerozero;     forcetable[0][1] = values.zeroone;     forcetable[0][2] = values.zerotwo;     forcetable[1][0] = values.onezero;     forcetable[1][1] = values.oneone;     forcetable[1][2] = values.onetwo;     forcetable[2][0] = values.twozero;     forcetable[2][1] = values.twoone;     forcetable[2][2] = values.twotwo;        }  public double returnvalue(forcetypes ifyouhave, forcetypes thenyouhave){     double factor = forcetable[thenyouhave.num][ifyouhave.num];     return factor; }

}

it's been long time since have programmed in java, , since activity starts fine without instantiating must java code forcetable. notice wrong? there's chance it's easy i'm not brushed on...

here logcat

08-08 18:08:13.206: e/(9801): : can't open file reading 08-08 18:08:13.206: e/(9801): : can't open file reading 08-08 18:10:34.045: w/dalvikvm(9801): threadid=1: thread exiting uncaught exception (group=0x4136b438) 08-08 18:10:34.045: e/androidruntime(9801): fatal exception: main 08-08 18:10:34.045: e/androidruntime(9801): java.lang.runtimeexception: unable start activity componentinfo{khandy.application.convertible/khandy.application.convertible.entryactivity}: java.lang.nullpointerexception 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread.performlaunchactivity(activitythread.java:2110) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread.handlelaunchactivity(activitythread.java:2135) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread.access$700(activitythread.java:143) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread$h.handlemessage(activitythread.java:1241) 08-08 18:10:34.045: e/androidruntime(9801): @ android.os.handler.dispatchmessage(handler.java:99) 08-08 18:10:34.045: e/androidruntime(9801): @ android.os.looper.loop(looper.java:137) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread.main(activitythread.java:4950) 08-08 18:10:34.045: e/androidruntime(9801): @ java.lang.reflect.method.invokenative(native method) 08-08 18:10:34.045: e/androidruntime(9801): @ java.lang.reflect.method.invoke(method.java:511) 08-08 18:10:34.045: e/androidruntime(9801): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1004) 08-08 18:10:34.045: e/androidruntime(9801): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:771) 08-08 18:10:34.045: e/androidruntime(9801): @ dalvik.system.nativestart.main(native method) 08-08 18:10:34.045: e/androidruntime(9801): caused by: java.lang.nullpointerexception 08-08 18:10:34.045: e/androidruntime(9801): @ khandy.application.convertible.forcetable.maketable(forcetable.java:34) 08-08 18:10:34.045: e/androidruntime(9801): @ khandy.application.convertible.forcetable.(forcetable.java:29) 08-08 18:10:34.045: e/androidruntime(9801): @ khandy.application.convertible.entryactivity.oncreate(entryactivity.java:21) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activity.performcreate(activity.java:5179) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1094) 08-08 18:10:34.045: e/androidruntime(9801): @ android.app.activitythread.performlaunchactivity(activitythread.java:2074) 08-08 18:10:34.045: e/androidruntime(9801): ... 11 more

you nullpointerexception @ line

forcetable[0][0] = values.zerozero;

because try access array without creating first. before accessing it, create that

forcetable = new double[][]; forcetable[0][0] = values.zerozero;

and please post logcat output! makes easier find problem.


-

Comments

Post a Comment

Popular posts from this blog

PySide and Qt Properties: Connecting signals from Python to QML -

i trying run simple pyside appliccation design made in qml. call function in qml python in separated thread. i have following qml view: import qt 4.7 rectangle { visible: true width: 100; height: 100 color: "lightgrey" text { id: datestr objectname: "datestr" x: 10 y: 10 text: "init text" font.pixelsize: 12 function updatedata(text) { datestr.text = qstr(text) console.log("you said: " + text) } } } here application: some imports.... #!/usr/bin/python import sys import time pyside import qtdeclarative, qtcore pyside.qtgui import qapplication pyside.qtdeclarative import qdeclarativeview the qthread worker.... #worker thread class worker(qtcore.qthread): updateprogress = qtcore.signal(int) def __init__(self, child): qtcore.qthread.__init__(self) self.child = child def run(self):
Read more

c# - DevExpress.Wpf.Grid.InfiniteGridSizeException was unhandled -

Image
when using devexpress, see error: devexpress.wpf.grid.infinitegridsizeexception unhandled message="by default, infinite grid height not allowed since grid rows rendered , hence grid work slowly. fix issue, should place grid container give finite height grid, or should manually specify grid's height or maxheight. note can avoid exception setting gridcontrol.allowinfinitegridsize static property true, in case grid run slowly." the problem dxgrid has infinite height. to fix, set height non-infinite. snoop absolutely invaluable this: if "height" xaml element infinite (i.e. 0 or nan ), can set using one of following: option 1: height="{binding path=actualheight, relativesource={relativesource mode=findancestor, ancestortype=uielement}}" option 2: verticalalignment="stretch" option 3: height="auto" hint: use verticalalignment="stretch" if child of grid <rowdefinition height=
Read more

scala - 'wrong top statement declaration' when using slick in IntelliJ -

Image
i'm porting project scala 2.9 2.10, therefore have use slick instead of scalaquery. i'm using slick 2.1.0 since supports ms access. according this tutorial , upgrade guide changed robs object class , added val robs : why error message wrong top statement declaration , how rid of it? edit: i'm new scala... according this question seems can't put val outside of methods or classes, right? code above directly in packge. right approach slick then? should move code in class or trait? according this changed val robs = tablequery[robs] to object robs extends tablequery(new robs(_)) {} . no warnings or errors anymore. :)
Read more