Android Camera unlock mediarecorder -
i want write app records video through smartphone camera. found website : http://developer.android.com/guide/topics/media/camera.html#custom-camera
im using source code started.
my main activity:
public class mainactivity extends activity { protected static final string tag = null; private camera mcamera; private camerapreview mpreview; private mediarecorder mmediarecorder=null; public static final int media_type_image = 1; public static final int media_type_video = 2; private boolean isrecording = false; /** safe way instance of camera object. */ public static camera getcamerainstance(){ camera c = null; try { c = camera.open(); // attempt camera instance } catch (exception e){ // camera not available (in use or not exist) } return c; // returns null if camera unavailable } @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); // create instance of camera mcamera = getcamerainstance(); // create our preview view , set content of our activity. mpreview = new camerapreview(this, mcamera); framelayout preview = (framelayout) findviewbyid(r.id.camera_preview); preview.addview(mpreview); // add listener capture button final button capturebutton = (button) findviewbyid(r.id.button_capture); capturebutton.setonclicklistener( new view.onclicklistener() { @override public void onclick(view v) { if (isrecording) { // stop recording , release camera mmediarecorder.stop(); // stop recording releasemediarecorder(); // release mediarecorder object mcamera.lock(); // take camera access mediarecorder // inform user recording has stopped capturebutton.settext("capture"); //setcapturebuttontext("capture"); isrecording = false; } else { // initialize video camera if (preparevideorecorder()) { // camera available , unlocked, mediarecorder prepared, // can start recording mmediarecorder.start(); // inform user recording has started capturebutton.settext("stop"); //setcapturebuttontext("stop"); isrecording = true; } else { // prepare didn't work, release camera releasemediarecorder(); // inform user } } } } ); } @suppresslint("newapi") private boolean preparevideorecorder(){ mcamera = getcamerainstance(); log.d(tag, "mcamera object: " + mcamera.getnumberofcameras()); mmediarecorder = new mediarecorder(); // step 1: unlock , set camera mediarecorder try{ mcamera.unlock(); }catch (runtimeexception r){ log.d(tag, "mcamera unlock: " + r.getmessage()); } mmediarecorder.setcamera(mcamera); // step 2: set sources mmediarecorder.setaudiosource(mediarecorder.audiosource.mic); mmediarecorder.setvideosource(mediarecorder.videosource.camera); // step 3: set camcorderprofile (requires api level 8 or higher) mmediarecorder.setprofile(camcorderprofile.get(camcorderprofile.quality_high)); // step 4: set output file mmediarecorder.setoutputfile(getoutputmediafile(media_type_video).tostring()); // step 5: set preview output mmediarecorder.setpreviewdisplay(mpreview.getholder().getsurface()); // step 6: prepare configured mediarecorder try { mmediarecorder.prepare(); } catch (illegalstateexception e) { log.d(tag, "illegalstateexception preparing mediarecorder: " + e.getmessage()); releasemediarecorder(); return false; } catch (ioexception e) { log.d(tag, "ioexception preparing mediarecorder: " + e.getmessage()); releasemediarecorder(); return false; } return true; } @override protected void onpause() { super.onpause(); releasemediarecorder(); // if using mediarecorder, release first releasecamera(); // release camera on pause event } private void releasemediarecorder(){ if (mmediarecorder != null) { mmediarecorder.reset(); // clear recorder configuration mmediarecorder.release(); // release recorder object mmediarecorder = null; mcamera.lock(); // lock camera later use } } private void releasecamera(){ if (mcamera != null){ mcamera.release(); // release camera other applications mcamera = null; } } /** create file saving image or video */ private static file getoutputmediafile(int type){ // safe, should check sdcard mounted // using environment.getexternalstoragestate() before doing this. file mediastoragedir = new file(environment.getexternalstoragepublicdirectory( environment.directory_pictures), "mycameraapp"); // location works best if want created images shared // between applications , persist after app has been uninstalled. // create storage directory if not exist if (! mediastoragedir.exists()){ if (! mediastoragedir.mkdirs()){ log.d("mycameraapp", "failed create directory"); return null; } } // create media file name string timestamp = new simpledateformat("yyyymmdd_hhmmss").format(new date()); file mediafile; if (type == media_type_image){ mediafile = new file(mediastoragedir.getpath() + file.separator + "img_"+ timestamp + ".jpg"); } else if(type == media_type_video) { mediafile = new file(mediastoragedir.getpath() + file.separator + "vid_"+ timestamp + ".mp4"); } else { return null; } return mediafile; } } my camera preview class:
/** basic camera preview class */ public class camerapreview extends surfaceview implements surfaceholder.callback { private surfaceholder mholder; private camera mcamera; private static final string tag = "preview"; public camerapreview(context context, camera camera) { super(context); mcamera = camera; // install surfaceholder.callback notified when // underlying surface created , destroyed. mholder = getholder(); mholder.addcallback(this); // deprecated setting, required on android versions prior 3.0 mholder.settype(surfaceholder.surface_type_push_buffers); } public void surfacecreated(surfaceholder holder) { // surface has been created, tell camera draw preview. try { mcamera.setpreviewdisplay(holder); mcamera.startpreview(); } catch (ioexception e) { log.d(tag, "error setting camera preview: " + e.getmessage()); } } public void surfacedestroyed(surfaceholder holder) { // empty. take care of releasing camera preview in activity. } public void surfacechanged(surfaceholder holder, int format, int w, int h) { // if preview can change or rotate, take care of events here. // make sure stop preview before resizing or reformatting it. if (mholder.getsurface() == null){ // preview surface not exist return; } // stop preview before making changes try { mcamera.stoppreview(); } catch (exception e){ // ignore: tried stop non-existent preview } // set preview size , make resize, rotate or // reformatting changes here // start preview new settings try { mcamera.setpreviewdisplay(mholder); mcamera.startpreview(); } catch (exception e){ log.d(tag, "error starting camera preview: " + e.getmessage()); } } } but when run app on samsung s5660 api 2.3.3 error:
06-07 19:55:48.859: d/(20274): mcamera object: 1 06-07 21:10:19.159: d/(20465): mcamera unlock: null 06-07 19:55:48.859: w/dalvikvm(20274): threadid=1: thread exiting uncaught exception (group=0x40018578) 06-07 19:55:48.859: e/androidruntime(20274): fatal exception: main 06-07 19:55:48.859: e/androidruntime(20274): java.lang.nullpointerexception 06-07 19:55:48.859: e/androidruntime(20274): @ com.example.videocapture.mainactivity.preparevideorecorder(mainactivity.java:118) 06-07 19:55:48.859: e/androidruntime(20274): @ com.example.videocapture.mainactivity.access$5(mainactivity.java:111) 06-07 19:55:48.859: e/androidruntime(20274): @ com.example.videocapture.mainactivity$1.onclick(mainactivity.java:91) 06-07 19:55:48.859: e/androidruntime(20274): @ android.view.view.performclick(view.java:2485) 06-07 19:55:48.859: e/androidruntime(20274): @ android.view.view$performclick.run(view.java:9080) 06-07 19:55:48.859: e/androidruntime(20274): @ android.os.handler.handlecallback(handler.java:587) 06-07 19:55:48.859: e/androidruntime(20274): @ android.os.handler.dispatchmessage(handler.java:92) 06-07 19:55:48.859: e/androidruntime(20274): @ android.os.looper.loop(looper.java:130) 06-07 19:55:48.859: e/androidruntime(20274): @ android.app.activitythread.main(activitythread.java:3687) 06-07 19:55:48.859: e/androidruntime(20274): @ java.lang.reflect.method.invokenative(native method) 06-07 19:55:48.859: e/androidruntime(20274): @ java.lang.reflect.method.invoke(method.java:507) 06-07 19:55:48.859: e/androidruntime(20274): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:867) 06-07 19:55:48.859: e/androidruntime(20274): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:625) 06-07 19:55:48.859: e/androidruntime(20274): @ dalvik.system.nativestart.main(native method) the null pointer exeception @ lin 118 preparevideorecorder():
// step 1: unlock , set camera mediarecorder mcamera.unlock(); when app starts camera displayed , when hit button "capture" error thrown. think problem "mcamera = getcamerainstance();" called again in function , first 1 created in main activity camera preview class.
i added logtag after "mcamera = getcamerainstance();" in preparevideorecorder() see if null cann see report says "06-07 19:55:48.859: d/(20274): mcamera object: 1"
the solution remove line mcamera = getcamerainstance(); in preparevideorecorder() function.
Comments
Post a Comment