in app want load image gallery or take image using camera , want apply parallax scrollview effect on image.i have xml file called header ,it contains image view , 2 buttons,one loading image 1 taking image using camera.i tried code app crashes when run app ,it shows runtime exception in logcat,can me find out problem??
logcat
06-03 12:39:02.683 27327-27327/? e/androidruntime﹕ fatal exception: main java.lang.runtimeexception: unable start activity componentinfo{in.zoid.parallaxtutorial/in.zoid.parallaxtutorial.mainactivity}: java.lang.nullpointerexception @ android.app.activitythread.performlaunchactivity(activitythread.java:2110) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2135) @ android.app.activitythread.access$700(activitythread.java:140) @ android.app.activitythread$h.handlemessage(activitythread.java:1237) @ android.os.handler.dispatchmessage(handler.java:99) @ android.os.looper.loop(looper.java:137) @ android.app.activitythread.main(activitythread.java:4921) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:511) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1027) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:794) @ dalvik.system.nativestart.main(native method) caused by: java.lang.nullpointerexception @ in.zoid.parallaxtutorial.mainactivity.oncreate(mainactivity.java:71) @ android.app.activity.performcreate(activity.java:5206) @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1094) @ android.app.activitythread.performlaunchactivity(activitythread.java:2074)
mainactivity.java public class mainactivity extends activity { private int lasttop = 0; //imageview image; listview listview; private static int result_load_image = 1; private static final int camera_request = 1888; private imageview imageview; arrayadapter adapter; arraylist<string> items = new arraylist<>(); public void parallax(final view v) { final rect r = new rect(); v.getlocalvisiblerect(r); if (lasttop != r.top) { lasttop = r.top; v.post(new runnable() { @override public void run() { v.sety((float) (r.top / 2.0)); } }); } } @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); listview = (listview) findviewbyid(r.id.listview); items.add("list item 1"); items.add("list item 2"); items.add("list item 3"); items.add("list item 4"); items.add("list item 5"); items.add("list item 6"); items.add("list item 7"); items.add("list item 8"); items.add("list item 9"); items.add("list item 10"); items.add("list item 11"); items.add("list item 12"); items.add("list item 13"); items.add("list item 14"); items.add("list item 15"); items.add("list item 16"); items.add("list item 17"); items.add("list item 18"); items.add("list item 19"); items.add("list item 20"); view view = getlayoutinflater().inflate(r.layout.header, null, false); button buttonloadimage = (button) findviewbyid(r.id.buttonloadpicture); buttonloadimage.setonclicklistener(new view.onclicklistener() { @override public void onclick(view arg0) { intent = new intent( intent.action_pick, android.provider.mediastore.images.media.external_content_uri); startactivityforresult(i, result_load_image); } }); this.imageview = (imageview)this.findviewbyid(r.id.imgview); /* button photobutton = (button) this.findviewbyid(r.id.button2); photobutton.setonclicklistener(new view.onclicklistener() { @override public void onclick(view v) { intent cameraintent = new intent(android.provider.mediastore.action_image_capture); startactivityforresult(cameraintent, camera_request); } });*/ //imageview block end // image = (imageview) view.findviewbyid(r.id.image); listview.addheaderview(view); adapter = new arrayadapter(this, android.r.layout.simple_list_item_1, items); listview.setadapter(adapter); adapter.notifydatasetchanged(); listview.setonscrolllistener(new abslistview.onscrolllistener() { @override public void onscrollstatechanged(abslistview view, int scrollstate) { parallax(imageview); } @override public void onscroll(abslistview view, int firstvisibleitem, int visibleitemcount, int totalitemcount) { parallax(imageview); } }); } } header.xml
<!--?xml version="1.0" encoding="utf-8"?--> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <imageview android:id="@+id/imgview" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_weight="1"></imageview> <relativelayout android:id="@+id/relativelayout1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:background="@android:color/black" > <button android:id="@+id/buttonloadpicture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="0" android:text="load picture" android:layout_gravity="center"></button> <button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="take picture" android:layout_alignparentright="true"/> </relativelayout> </linearlayout>
i think problem here:
button buttonloadimage = (button) findviewbyid(r.id.buttonloadpicture); you should use this
button buttonloadimage = (button) view.findviewbyid(r.id.buttonloadpicture); because header not added activity layout yet, code null pointer when find buttonloadpicture.
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