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PONull Pointer Exception occuring during graph generation
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2012-02-10T12:19:17.047
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Friends.. I am trying to drawing some graph. My application is running fine for first attempt but when I am trying to draw the graph repeatedly for 2,3 attempts then it is showing Null Pointer exception...What will be the solution? Here is my code: <pre><code>public class ECG extends Activity { /** Called when the activity is first created. */ Context cnt; Callback c; Camera mCamera; boolean mFinished; DrawMyGraph g; ImageView clock,graph_Text,heart_Index,graph_View; static long startTime = 0; static int beats = 0; volatile boolean show=false; SurfaceHolder sh; SurfaceView sv; TextView show_BPM; Button on,off; int no,count=0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); show_BPM=(TextView)findViewById(R.id.showBPM); sv=(SurfaceView)findViewById(R.id.surfaceView1); clock=(ImageView)findViewById(R.id.clock); graph_Text=(ImageView)findViewById(R.id.graphText); heart_Index=(ImageView)findViewById(R.id.heartIndex); graph_View=(ImageView)findViewById(R.id.graphview); graph_Text.setBackgroundResource(R.drawable.graphtext2); on=(Button)findViewById(R.id.on); off=(Button)findViewById(R.id.off); Random r=new Random(); no=r.nextInt(84-60)+60; Context context = getApplicationContext(); CharSequence text = "cover the camera with your index finger......!"; int duration = 100000; Toast toast = Toast.makeText(context, text, duration); toast.show(); /////////////////////////////// //////////////////////////// g = new DrawMyGraph(this, 26); addContentView(g, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); startCamPreview(); } public void startCamPreview() { SurfaceView sv = (SurfaceView) findViewById(R.id.surfaceView1); SurfaceHolder sh = sv.getHolder(); mCamera = Camera.open(); try { mCamera.setPreviewDisplay(sh); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } sh.addCallback(new Callback() { @Override public void surfaceDestroyed(SurfaceHolder holder) { // TODO Auto-generated method stub System.out.println("Deleted"); mCamera.setPreviewCallback(null); mCamera.stopPreview(); mCamera.release(); mCamera = null; } @Override public void surfaceCreated(SurfaceHolder holder) { System.out.println("Created"); mCamera.setPreviewCallback(new PreviewCallback() { public void onPreviewFrame(byte[] data, Camera camera) { Camera.Parameters params = camera.getParameters(); int width = params.getPreviewSize().width; int height = params.getPreviewSize().height; byte[] mYUVData = new byte[data.length]; int[] mRGBData = new int[width * height]; System.arraycopy(data, 0, mYUVData, 0, data.length); decodeYUV420SP(mRGBData, mYUVData, width, height); int[] mRedHistogram = new int[256]; calculateIntensityHistogram(mRGBData, mRedHistogram, width, height, 0); double imageRedMean = 0; double redHistogramSum = 0; for (int bin = 0; bin < 256; bin++) { imageRedMean += mRedHistogram[bin] * bin; redHistogramSum += mRedHistogram[bin]; } // bin imageRedMean /= redHistogramSum; double[] mBinSquared; mBinSquared = new double[256]; for (int bin = 0; bin < 256; bin++) { mBinSquared[bin] = ((double) bin) * bin; } double imageRed2ndMoment = 0; for (int bin = 0; bin < 256; bin++) { imageRed2ndMoment += mRedHistogram[bin] * mBinSquared[bin]; } // bin imageRed2ndMoment /= redHistogramSum; double imageRedStdDev = Math.sqrt((imageRed2ndMoment - imageRedMean * imageRedMean)); int val = (new Double(imageRedStdDev * 100000) .intValue()); show_BPM.setText(String.valueOf(no)); int v = new Double(imageRedStdDev).intValue(); for (int l = 0; l < 1; l++) { } int yVal=250; if (imageRedStdDev < 15 && val != 0) { show=true; g.addPoint(yVal); g.addPoint(yVal); float flt=(float)Math.random(); g.addPoint(yVal+flt*25); g.addPoint(yVal); g.addPoint(yVal); flt=(float)Math.random(); g.addPoint(yVal-flt*20); g.addPoint(yVal); g.addPoint(yVal); flt=(float)Math.random(); g.addPoint(yVal-flt*30); g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); flt=(float)Math.random(); g.addPoint(yVal+flt*35); try { Thread.sleep(500); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } else { show=false; if(val==0){ count++; g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); show_BPM.setText(String.valueOf(0)); }else{ count++; g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); g.addPoint(yVal); show_BPM.setText(String.valueOf(0)); } } } }); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { System.out.println("Changed"); Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(320, 240); parameters.setPreviewFrameRate(15); parameters.setSceneMode(Camera.Parameters.SCENE_MODE_NIGHT); parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO); mCamera.setParameters(parameters); mCamera.startPreview(); g.invalidate(); } }); // fl.addView(b); } static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) { final int frameSize = width * height; for (int j = 0, yp = 0; j < height; j++) { int uvp = frameSize + (j >> 1) * width, u = 0, v = 0; for (int i = 0; i < width; i++, yp++) { int y = (0xff & ((int) yuv420sp[yp])) - 16; if (y < 0) y = 0; if ((i & 1) == 0) { v = (0xff & yuv420sp[uvp++]) - 128; u = (0xff & yuv420sp[uvp++]) - 128; } int y1192 = 1192 * y; int r = (y1192 + 1634 * v); int g = (y1192 - 833 * v - 400 * u); int b = (y1192 + 2066 * u); if (r < 0) r = 0; else if (r > 262143) r = 262143; if (g < 0) g = 0; else if (g > 262143) g = 262143; if (b < 0) b = 0; else if (b > 262143) b = 262143; rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff); } } } static public void calculateIntensityHistogram(int[] rgb, int[] histogram, int width, int height, int component) { for (int bin = 0; bin < 256; bin++) { histogram[bin] = 0; } // bin if (component == 0) // red { for (int pix = 0; pix < width * height; pix += 3) { int pixVal = (rgb[pix] >> 16) & 0xff; histogram[pixVal]++; } // pix } else if (component == 1) // green { for (int pix = 0; pix < width * height; pix += 3) { int pixVal = (rgb[pix] >> 8) & 0xff; histogram[pixVal]++; } // pix } else // blue { for (int pix = 0; pix < width * height; pix += 3) { int pixVal = rgb[pix] & 0xff; histogram[pixVal]++; } // pix } } public void onWindowFocusChanged(boolean hasFocus) { super.onWindowFocusChanged(hasFocus); clock.setBackgroundResource(R.anim.clockanimation); AnimationDrawable clock_Anim=new AnimationDrawable(); clock_Anim=(AnimationDrawable)clock.getBackground(); clock_Anim.start(); timer.start(); } CountDownTimer timer=new CountDownTimer(30000,1000){ @Override public void onFinish()throws NullPointerException { // TODO Auto-generated method stub mCamera.stopPreview();**//This is the line for which shows NullPointer exception** g.invalidate(); Canvas.freeGlCaches(); graph_Text.setBackgroundResource(R.drawable.graphtext3); if(count>0) { System.out.println("Hiiiiiii"); show_BPM.setText(String.valueOf(0)); } else { System.out.println("Helllooo"); show_BPM.setText(String.valueOf(no)); } } @Override public void onTick(long arg0) { // TODO Auto-generated method stub } }; class DrawMyGraph extends View { public LinkedList<Float> yValues = null; private int size = 0; private LinkedList<Integer> xValues = null; private LinkedList<Long> beatList = new LinkedList<Long>(); public DrawMyGraph(Context context, int size) { super(context); yValues = new LinkedList<Float>(); int inc = 5; this.size = size * inc; xValues = new LinkedList<Integer>(); int cnt = 468; for (int i = 0; i < this.size * inc; i++) { xValues.add(cnt); cnt = cnt - (inc - 2); } } @Override protected void onDraw(Canvas canvas) { Bitmap bitmap=Bitmap.createBitmap(2 , 2, Bitmap.Config.RGB_565); graph_View.setImageBitmap(bitmap); Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setStyle(Paint.Style.STROKE); paint.setStrokeWidth(2); paint.setColor(Color.RED); invalidate(); for (int i = 0, j = 1; i < yValues.size() && j < yValues.size(); i++, j++) { canvas.drawLine(xValues.get(i) + 30, (yValues.get(i) - 10)*2, xValues.get(j) + 30, (yValues.get(j) - 10)*2, paint); } super.onDraw(canvas); } public int getSize() { return size; } public void addPoint(float p) { if (yValues.size() > size) { yValues.removeLast(); } yValues.addFirst(p); } public void addBeat(long beat) { beatList.add(beat); } } public void onBackPressed() { finish(); return; } } </code></pre> this is what my logcat saying <blockquote> 02-10 17:34:25.570: W/dalvikvm(3681): threadid=1: thread exiting with uncaught exception (group=0x40015578) 02-10 17:34:25.574: E/AndroidRuntime(3681): FATAL EXCEPTION: main 02-10 17:34:25.574: E/AndroidRuntime(3681): java.lang.NullPointerException 02-10 17:34:25.574: E/AndroidRuntime(3681): at com.android.ecg.ECG$1.onFinish(ECG.java:312) 02-10 17:34:25.574: E/AndroidRuntime(3681): at android.os.CountDownTimer$1.handleMessage(CountDownTimer.java:118) 02-10 17:34:25.574: E/AndroidRuntime(3681): at android.os.Handler.dispatchMessage(Handler.java:99) 02-10 17:34:25.574: E/AndroidRuntime(3681): at android.os.Looper.loop(Looper.java:123) 02-10 17:34:25.574: E/AndroidRuntime(3681): at android.app.ActivityThread.main(ActivityThread.java:3687) 02-10 17:34:25.574: E/AndroidRuntime(3681): at java.lang.reflect.Method.invokeNative(Native Method) 02-10 17:34:25.574: E/AndroidRuntime(3681): at java.lang.reflect.Method.invoke(Method.java:507) 02-10 17:34:25.574: E/AndroidRuntime(3681): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842) 02-10 17:34:25.574: E/AndroidRuntime(3681): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600) 02-10 17:34:25.574: E/AndroidRuntime(3681): at dalvik.system.NativeStart.main(Native Method) </blockquote>
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<android><graph><nullpointerexception>
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Null Pointer Exception occuring during graph generation
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