Android Camera Will Not Work. Startpreview Fails

Android Camera will not work. startPreview fails

I took your code and got the same error as you. However, on debugging it appears to me that the preview might be failing because it seemed like the width and height dimensions were round the wrong way but its not just a case of switching them around as I think the orientation also plays a part.

Anyway, I've substituted your CameraSurfaceView with my own (see below) and I think it works now. There is no exception but the screen is completely bright green (I think this might be because I don't have the vertex.vsh or the fragment.vsh files.

package stackOverflow.test;

import java.io.IOException;
import java.util.List;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Display;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;

public class CameraSurfaceView extends ViewGroup implements SurfaceHolder.Callback
{

private Size mPreviewSize;
private List<Size> mSupportedPreviewSizes;        
private Context mContext;
private SurfaceView mSurfaceView;
private SurfaceHolder mHolder;
private final String TAG = "CameraSurfaceView";
private Camera mCamera;
private List<String> mSupportedFlashModes;

public CameraSurfaceView(Context context)
{
    super(context);
    mContext = context;
    mCamera = Camera.open();        
    setCamera(mCamera);

    mSurfaceView = new SurfaceView(context);
    addView(mSurfaceView, 0);        
    mHolder = mSurfaceView.getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    mHolder.setKeepScreenOn(true);
}

public CameraSurfaceView(Context context, AttributeSet attrs)
{
    super(context, attrs);
    mContext = context;            
}

public void setSupportedPreviewSizes(List<Size> supportedPreviewSizes)
{
    mSupportedPreviewSizes = supportedPreviewSizes;
}

public Size getPreviewSize()
{
    return mPreviewSize;
}

public void setCamera(Camera camera)
{
    mCamera = camera;
    if (mCamera != null)
    {
        mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();                
        mSupportedFlashModes = mCamera.getParameters().getSupportedFlashModes();
        // Set the camera to Auto Flash mode.
        if (mSupportedFlashModes.contains(Camera.Parameters.FLASH_MODE_AUTO))
        {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);             
            mCamera.setParameters(parameters);
        }                   
    }
    requestLayout();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder)
{
    // Surface will be destroyed when we return, so stop the preview.
    if (mCamera != null)
    {
        mCamera.stopPreview();
    }
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)
{
    // Now that the size is known, set up the camera parameters and begin
    // the preview.
    if (mCamera != null)
    {
        Camera.Parameters parameters = mCamera.getParameters();        
        Size previewSize = getPreviewSize();
        parameters.setPreviewSize(previewSize.width, previewSize.height);                

        mCamera.setParameters(parameters);
        mCamera.startPreview();
    }

}

@Override
public void surfaceCreated(SurfaceHolder holder)
{
    // The Surface has been created, acquire the camera and tell it where
    // to draw.
    try
    {
        if (mCamera != null)
        {
            mCamera.setPreviewDisplay(holder);
        }
    }
    catch (IOException exception)
    {
        Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{        
    final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
    final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
    setMeasuredDimension(width, height);

    if (mSupportedPreviewSizes != null)
    {
        mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
    }
}

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom)
{
    if (changed)
    {                            
        final View cameraView = getChildAt(0);          

        final int width = right - left;
        final int height = bottom - top;

        int previewWidth = width;
        int previewHeight = height;
        if (mPreviewSize != null)
        {
            Display display = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

            switch (display.getRotation())
            {
                case Surface.ROTATION_0:
                    previewWidth = mPreviewSize.height;
                    previewHeight = mPreviewSize.width;
                    mCamera.setDisplayOrientation(90);
                    break;
                case Surface.ROTATION_90:
                    previewWidth = mPreviewSize.width;
                    previewHeight = mPreviewSize.height;
                    break;
                case Surface.ROTATION_180:
                    previewWidth = mPreviewSize.height;
                    previewHeight = mPreviewSize.width;
                    break;
                case Surface.ROTATION_270:
                    previewWidth = mPreviewSize.width;
                    previewHeight = mPreviewSize.height;
                    mCamera.setDisplayOrientation(180);
                    break;
            }                                    
        }

        final int scaledChildHeight = previewHeight * width / previewWidth;

        cameraView.layout(0, height - scaledChildHeight, width, height);

    }
}


private Size getOptimalPreviewSize(List<Size> sizes, int width, int height)
{           
    Size optimalSize = null;                                

    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio = (double) height / width;

    // Try to find a size match which suits the whole screen minus the menu on the left.
    for (Size size : sizes)
    {
        if (size.height != width) continue;
        double ratio = (double) size.width / size.height;
        if (ratio <= targetRatio + ASPECT_TOLERANCE && ratio >= targetRatio - ASPECT_TOLERANCE)
        {
            optimalSize = size;
        }               
    }

    // If we cannot find the one that matches the aspect ratio, ignore the requirement.
    if (optimalSize == null)
    {
        // TODO : Backup in case we don't get a size.
    }

    return optimalSize;
}

public void previewCamera()
{        
    try 
    {           
        mCamera.setPreviewDisplay(mHolder);         
        mCamera.startPreview();                 
    }
    catch(Exception e)
    {
        Log.d(TAG, "Cannot start preview.", e);    
    }
}


/*public void onPreviewFrame(byte[] data, Camera arg1) { 
    Log.d("CameraSurfaceView", "PREVIEW FRAME:"); 
    byte[] pixels = new byte[use_size.width * use_size.height * 3]; ; 
    decodeYUV420SP(pixels, data, use_size.width,  use_size.height);  
    renderer.bindCameraTexture(pixels, use_size.width,  use_size.height); 
}*/ 

void decodeYUV420SP(byte[] 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*3] = (byte) (b << 6); 
            rgb[yp*3 + 1] = (byte) (b >> 2); 
            rgb[yp*3 + 2] = (byte) (b >> 10); 
        }   
    }   
  }   
}

You'll notice I commented out your onPreviewFrame() method just to get it running and also the line context.surface_view.renderer = renderer.

I'm not familiar with the OpenGL library but perhaps this is enough to get you going again.

Camera not working - startPreview fails

On your SurfaceView Holder, make sure to set the type to SURFACE_TYPE_PUSH_BUFFERS

@Override
public void onCreate(Bundle savedInstanceState) {
   // ...
   SurfaceView s=(SurfaceView)findViewById(R.id.surface);
   SurfaceHolder h=s.getHolder();
   h.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

Android camea startPreview() fails when taking multiple pictures

Thanks for the suggestion from Alex Cohn, I found a solution. This solution is only tested on the HTC Sensation device, but it has dramatic effect on this device.

I just put a sleep instruction before startPreview() that would be called in onPictureTaken():

try
{
    Thread.sleep(20);
}
catch (Exception e)
{
    e.printStackTrace();
}

Then I run a test 100 times, where each run takes 3 pictures in succession. With the sleep, I didn't get any error from startPreview() in 100 runs. If There is no sleep, I need to reopen the camera 78 times, and restart the device 8 times in 100 runs.

camera startPreview failed

I have solved deleting some lines in surfaceChanged

 public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.
        Log.d("Function", "surfaceChanged iniciado");
        if (mHolder.getSurface() == null){
          // preview surface does not exist
          return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
          // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or
        // reformatting changes here


        // start preview with new settings
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

So the error must be in i one of these lines:

Parameters parameters= mCamera.getParameters();
    parameters.setPreviewSize(w, h);
    mCamera.setParameters(parameters);

Someone could explain me what was wrong in those lines?

android.hardware.Camera fails to open every second time

Here is my onStop and onResume methods. I'm not using onPause. And it works perfectly:

  @Override
    protected void onResume() {
        super.onResume();
        if (mCamera == null) {
            restartPreview();
        }
    }
    @Override
    public void onStop() {

        // stop the preview
        if (mCamera != null) {
            stopCameraPreview();
            mCamera.release();
            mCamera = null;
        }

        super.onStop();
    }

 private void restartPreview() {
        if (mCamera != null) {
            stopCameraPreview();
            mCamera.release();
            mCamera = null;
        }



            getCamera(mCameraID);
            startCameraPreview();
        }

private void startCameraPreview() {


        try {
            mCamera.setPreviewDisplay(mSurfaceHolder);
            mCamera.startPreview();

            setSafeToTakePhoto(true);
            setCameraFocusReady(true);
        } catch (IOException e) {
            Log.d("st", "Can't start camera preview due to IOException " + e);
            e.printStackTrace();
        }
    }

 private void stopCameraPreview() {
        setSafeToTakePhoto(false);
        setCameraFocusReady(false);

        // Nulls out callbacks, stops face detection
        mCamera.stopPreview();
        mPreviewView.setCamera(null);
    }

maybe some implementations not equals yours but i think it is help you.

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