How to capture image automatically when application start in android? -

hi friends working on application.

in application when application start pic should automatically captured camera.

my code is:

1. camera demo

    public class camerademo extends activity      {         private static final string tag = "camerademo";         camera camera;         preview preview;         button buttonclick;         chronometer ch;          /** called when activity first created. */         @override       public void oncreate(bundle savedinstancestate)          {             super.oncreate(savedinstancestate);             setcontentview(r.layout.main);              preview = new preview(this);             ((framelayout) findviewbyid(r.id.preview)).addview(preview);              buttonclick = (button) findviewbyid(r.id.buttonclick);             ch=(chronometer)findviewbyid(r.id.chronometer1);             ch.start();              preview.camera.takepicture(shuttercallback,rawcallback,jpegcallback);        // if write above code here shows error.              buttonclick.setonclicklistener( new onclicklistener()              {                 public void onclick(view v)                  {                      buttonclick.setvisibility(view.invisible);                     preview.camera.takepicture(shuttercallback, rawcallback,jpegcallback);                                // here works perfactly                     toast.maketext(camerademo.this,""+ch.gettext(), toast.length_long).show();                 }             });              log.d(tag, "oncreate'd");         }           shuttercallback shuttercallback = new shuttercallback()          {             public void onshutter()              {                 log.d(tag, "onshutter'd");             }         };          /** handles data raw picture */         picturecallback rawcallback = new picturecallback()          {             public void onpicturetaken(byte[] data, camera camera)              {                 log.d(tag, "onpicturetaken - raw");             }         };          /** handles data jpeg picture */         picturecallback jpegcallback = new picturecallback()          {             public void onpicturetaken(byte[] data, camera camera)              {                 fileoutputstream outstream = null;                 try                 {                     // write local sandbox file system                     // outstream = camerademo.this.openfileoutput(string.format("%d.jpg", system.currenttimemillis()), 0);                       // or write sdcard                     outstream = new fileoutputstream(string.format("/sdcard/tmp/%d.jpg", system.currenttimemillis()));                       outstream.write(data);                     outstream.close();                     log.d(tag, "onpicturetaken - wrote bytes: " + data.length);                 }                 catch (filenotfoundexception e)                  {                     e.printstacktrace();                 }                 catch (ioexception e)                  {                     e.printstacktrace();                 }                                  {                 }                 log.d(tag, "onpicturetaken - jpeg");             }         };      } 

2. preview.java

package com.example;  import java.io.filenotfoundexception; import java.io.fileoutputstream; import java.io.ioexception;  import android.content.context; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.hardware.camera; import android.hardware.camera.previewcallback; import android.util.log; import android.view.surfaceholder; import android.view.surfaceview;   class preview extends surfaceview implements surfaceholder.callback {     private static final string tag = "preview";      surfaceholder mholder;     public camera camera;      @suppresswarnings("deprecation")     preview(context context)     {         super(context);          // install surfaceholder.callback notified when         // underlying surface created , destroyed.         mholder = getholder();         mholder.addcallback(this);         mholder.settype(surfaceholder.surface_type_push_buffers);     }      public void surfacecreated(surfaceholder holder)      {         // surface has been created, acquire camera , tell         // draw.         camera = camera.open();         try          {             camera.setpreviewdisplay(holder);              camera.setpreviewcallback(new previewcallback()              {                  public void onpreviewframe(byte[] data, camera arg1)                  {                     fileoutputstream outstream = null;                     try                      {                         outstream = new fileoutputstream(string.format("/sdcard/tmp/%d.jpg", system.currenttimemillis()));                           outstream.write(data);                         outstream.close();                         log.d(tag, "onpreviewframe - wrote bytes: " + data.length);                     }                     catch (filenotfoundexception e)                      {                         e.printstacktrace();                     }                     catch (ioexception e)                      {                         e.printstacktrace();                     }                                          {                     }                         preview.this.invalidate();                 }             });         }         catch (ioexception e)          {             e.printstacktrace();         }     }      public void surfacedestroyed(surfaceholder holder)      {         // surface destroyed when return, stop preview.         // because cameradevice object not shared resource, it's         // important release when activity paused.         camera.stoppreview();         camera = null;     }      public void surfacechanged(surfaceholder holder, int format, int w, int h)      {         // size known, set camera parameters , begin         // preview.         camera.parameters parameters = camera.getparameters();         parameters.setpreviewsize(w, h);         camera.setparameters(parameters);         camera.startpreview();     }      @override     public void draw(canvas canvas)      {             super.draw(canvas);             paint p= new paint(color.red);             log.d(tag,"draw");             canvas.drawtext("preview", canvas.getwidth()/2, canvas.getheight()/2, p );     } } 

for had given above permisson:

<uses-permission android:name="android.permission.camera" />

my error log is:

fatal exception: main java.lang.runtimeexception: unable start activity componentinfo{com.example/com.example.camerademo}: java.lang.nullpointerexception     @ android.app.activitythread.performlaunchactivity(activitythread.java:2343)     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2395)     @ android.app.activitythread.access$600(activitythread.java:162)     @ android.app.activitythread$h.handlemessage(activitythread.java:1364)     @ android.os.handler.dispatchmessage(handler.java:107)     @ android.os.looper.loop(looper.java:194)     @ android.app.activitythread.main(activitythread.java:5371)     @ java.lang.reflect.method.invokenative(native method)     @ java.lang.reflect.method.invoke(method.java:525)     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:833)     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:600)     @ dalvik.system.nativestart.main(native method) caused by: java.lang.nullpointerexception     @ com.example.camerademo.oncreate(camerademo.java:41)     @ android.app.activity.performcreate(activity.java:5122)     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1081)     @ android.app.activitythread.performlaunchactivity(activitythread.java:2307)     ... 11 more 

my problem is:

when using code in button click event work perfectly. need when start application image should capture automatically.

same code not working in oncreate() event , application stops unfortunately.

please tell solution of this.

thank you.

your surfaceview not yet created when call

preview.camera.takepicture(shuttercallback,rawcallback,jpegcallback);

so camera null @ time..

try call after dealy..

  @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.camera);         preview = new preview(this);          ((framelayout) findviewbyid(r.id.preview)).addview(preview);          new java.util.timer().schedule(                  new java.util.timertask() {                     @override                     public void run() {                         // code here                          preview.camera.takepicture(shuttercallback,rawcallback,jpegcallback);                     }                 },                  2000          );       } 

this works perfect me... hope works too.. best luck :)