android - capturing image and displaying -
i trying click images camera , displaying them in gridview. using below code getting "unfortunately camera has stopped working" error. please suggest
logcat:beginning of crash**07-09 01:14:01.734 3873-3873/? e/androidruntime﹕ fatal exception: main process: com.example.sakshi.intel, pid: 3873 java.lang.runtimeexception: unable start activity componentinfo{com.example.sakshi.intel/com.example.sakshi.intel.mainactivity}: java.lang.nullpointerexception: attempt invoke interface method 'int java.util.list.size()' on null object reference @ android.app.activitythread.performlaunchactivity(activitythread.java:2298) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2360) @ android.app.activitythread.access$800(activitythread.java:144) @ android.app.activitythread$h.handlemessage(activitythread.java:1278) @ android.os.handler.dispatchmessage(handler.java:102) @ android.os.looper.loop(looper.java:135) @ android.app.activitythread.main(activitythread.java:5221) @ java.lang.reflect.method.invoke(native method) @ java.lang.reflect.method.invoke(method.java:372) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:899) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:694) caused by: java.lang.nullpointerexception: attempt invoke interface method 'int java.util.list.size()' on null object reference @ com.example.sakshi.intel.mainactivity$imageadapter.getcount(mainactivity.java:89) @ android.widget.gridview.setadapter(gridview.java:201) @ com.example.sakshi.intel.mainactivity.oncreate(mainactivity.java:45) @ android.app.activity.performcreate(activity.java:5933) @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1105) @ android.app.activitythread.performlaunchactivity(activitythread.java:2251) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2360) @ android.app.activitythread.access$800(activitythread.java:144) @ android.app.activitythread$h.handlemessage(activitythread.java:1278) @ android.os.handler.dispatchmessage(handler.java:102) @ android.os.looper.loop(looper.java:135) @ android.app.activitythread.main(activitythread.java:5221) @ java.lang.reflect.method.invoke(native method) @ java.lang.reflect.method.invoke(method.java:372)**
using below code: activity_main.xml`
<button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="photo" android:onclick="takepicture"/> <gridview android:id="@+id/gridview1" android:layout_width="match_parent" android:layout_height="wrap_content"></gridview> `
mainactivity.java public class mainactivity extends actionbaractivity {
private list<string> mylist; // string list contains file paths images private gridview gridview; private string mcurrentphotopath; // file path last image captured static final int request_take_photo = 1; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); // initialize gridview gridview = (gridview) findviewbyid(r.id.gridview1); gridview.setadapter(new imageadapter(this)); // initialize gridview thumbnail click handler /*gridview.setonitemclicklistener(new adapterview.onitemclicklistener() { @override public void onitemclick(adapterview<?> parent, view v, int position, long id) { // send file path image display activity intent intent = new intent(getapplicationcontext(), imagedisplayactivity.class); intent.putextra("path", mylist.get(position)); startactivity(intent); } });*/ } @override public boolean oncreateoptionsmenu(menu menu) { // inflate menu; adds items action bar if present. getmenuinflater().inflate(r.menu.menu_main, menu); return true; } @override public boolean onoptionsitemselected(menuitem item) { // handle action bar item clicks here. action bar // automatically handle clicks on home/up button, long // specify parent activity in androidmanifest.xml. int id = item.getitemid(); //noinspection simplifiableifstatement if (id == r.id.action_settings) { return true; } return super.onoptionsitemselected(item); } public class imageadapter extends baseadapter { private context mcontext; public imageadapter(context c) { mcontext = c; } public int getcount() { return mylist.size(); } public object getitem(int position) { return null; } public long getitemid(int position) { return 0; } public view getview(int position, view convertview, viewgroup parent) { imageview imageview; if (convertview == null) { imageview = new imageview(mcontext); imageview.setlayoutparams(new gridview.layoutparams(85, 85)); imageview.setscaletype(imageview.scaletype.center_crop); imageview.setpadding(8, 8, 8, 8); } else { imageview = (imageview) convertview; } bitmapfactory.options bmoptions = new bitmapfactory.options(); bmoptions.injustdecodebounds = false; bmoptions.insamplesize = 4; bmoptions.inpurgeable = true; bitmap bitmap = bitmapfactory.decodefile(mylist.get(position), bmoptions); imageview.setimagebitmap(bitmap); return imageview; } } private void takepicture() { intent takepictureintent = new intent(mediastore.action_image_capture ); if (takepictureintent.resolveactivity(getpackagemanager()) != null) { file photofile = null; try { photofile = createimagefile(); } catch (ioexception ex) { // error occurred while creating file } // continue if file created if (photofile != null) { takepictureintent.putextra(mediastore. extra_output, uri. fromfile(photofile)); startactivityforresult(takepictureintent, request_take_photo); } } } private file createimagefile() throws ioexception { // create image file name string timestamp = new simpledateformat("yyyymmdd_hhmmss").format( new date()); string imagefilename = "jpeg_" + timestamp + "_" ; file storagedir = environment.getexternalstoragepublicdirectory(environment.directory_pictures); file image = file. createtempfile( imagefilename, /* prefix */ ".jpg", /* suffix */ storagedir /* directory */ ); // save file: path use action_view intents mcurrentphotopath = image.getabsolutepath(); return image; } @override protected void onactivityresult(int requestcode, int resultcode, intent data) { if (requestcode == request_take_photo && resultcode == result_ok) { // save image gallery intent mediascanintent = new intent(intent.action_media_scanner_scan_file ); file f = new file(mcurrentphotopath ); uri contenturi = uri.fromfile(f); mediascanintent.setdata(contenturi); this.sendbroadcast(mediascanintent); // add image path list mylist.add( mcurrentphotopath); // refresh gridview image thumbnails gridview.invalidateviews(); } } }
you trying access size of list, mylist in getcount(), inside imageadapter class. , exception happened.
the exception occurred because mylist null object.
why null? possibly because in mylist.add( mcurrentphotopath); inside onactivityresult, value of mcurrentphotopath might null.
add check inside onactivityresult :
if (mcurrentphotopath != null) { mylist.add(mcurrentphotopath); } else { // can't access image file path.show toast or something. }
now, experience phone manufactures return file path, return bitmap of image captured. not sure, might return both. expecting access file path of captured image won't app.
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