java - context is null in custom view -

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i'm working on custom view extends horizontalscrollview , i'm doing following code:

public bottomnavigation(context context) {     super(context, null, 0); }  public bottomnavigation(context context, attributeset attrs) {     super(context, attrs, 0); }  public bottomnavigation(context context, attributeset attrs, int defstyleattr) {     super(context, attrs, defstyleattr);     this.context = context; }  @override protected void onsizechanged(int w, int h, int oldw, int oldh) {     super.onsizechanged(w, h, oldw, oldh);     createitems(); }  public void createitems() {     if (items < 4) {         return;     }     height = getheight();     width = getwidth();     paddingtop = height / 7;     itemsheight = height - paddingtop;     itemswidth = width / 4;     requestlayout();     views.clear();     removeallviews();     linearlayout linearlayout = new linearlayout(context);     linearlayout.setorientation(linearlayout.horizontal);     linearlayout.layoutparams layoutparams = new linearlayout.layoutparams(height, viewgroup.layoutparams.wrap_content);     linearlayout.setlayoutparams(layoutparams);     addview(linearlayout);     for(int i=0;i<items;i++)     {         linearlayout linearlayout1 = new linearlayout(context);         linearlayout.layoutparams layoutparams1 = new linearlayout.layoutparams(height, itemswidth);         linearlayout1.setlayoutparams(layoutparams1);         linearlayout1.setorientation(linearlayout.vertical);     } }

but i'm getting error when running application:

 java.lang.runtimeexception: unable start activity componentinfo{com.example.amir_p.bottomnavigation3/com.example.amir_p.bottomnavigation3.mainactivity}: java.lang.nullpointerexception: attempt invoke virtual method 'android.content.res.resources android.content.context.getresources()' on null object reference       @ android.app.activitythread.performlaunchactivity(activitythread.java:2450)       @ android.app.activitythread.handlelaunchactivity(activitythread.java:2510)       @ android.app.activitythread.-wrap11(activitythread.java)       @ android.app.activitythread$h.handlemessage(activitythread.java:1363)       @ android.os.handler.dispatchmessage(handler.java:102)       @ android.os.looper.loop(looper.java:148)       @ android.app.activitythread.main(activitythread.java:5459)       @ java.lang.reflect.method.invoke(native method)       @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:726)       @ com.android.internal.os.zygoteinit.main(zygoteinit.java:616)    caused by: java.lang.nullpointerexception: attempt invoke virtual method 'android.content.res.resources android.content.context.getresources()' on null object reference       @ android.view.viewconfiguration.get(viewconfiguration.java:366)       @ android.view.view.<init>(view.java:3794)       @ android.view.view.<init>(view.java:3898)       @ android.view.viewgroup.<init>(viewgroup.java:573)       @ android.widget.linearlayout.<init>(linearlayout.java:203)       @ android.widget.linearlayout.<init>(linearlayout.java:199)       @ android.widget.linearlayout.<init>(linearlayout.java:195)       @ android.widget.linearlayout.<init>(linearlayout.java:191)       @ com.example.amir_p.bottomnavigation3.bottomnavigation.createitems(bottomnavigation.java:68)       @ com.example.amir_p.bottomnavigation3.bottomnavigation.setitems(bottomnavigation.java:108)

after debugging noticed context null why? problem?

you initialize context member variable in 1 of 3 constructors , apparently either 1 of other 2 invoked.

in custom view, don't need store context reference yourself. call getcontext() whenever need context.


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