Whenever I run the cam_thread I get the error "app passed NULL surface". This code supposedly works on the HTC Incredible 1. I've reconfigured it slightly to run on a droid x. However I still get this error.
public class Android_Activity extends Activity
{
Main_thread simulator;
ToggleButton togglebutton;
EditText ip_text;
SensorManager sm = null;
SurfaceView view;
Sensors_thread the_sensors=null;
String IP_address;
Android_Activity the_app;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
view = new SurfaceView(this);
sm = (SensorManager) getSystemService(SENSOR_SERVICE);
ip_text = (EditText) findViewById(R.id.IP_edit_txt);
togglebutton = (ToggleButton) findViewById(R.id.CameraButton);
togglebutton.setOnClickListener(new btn_listener());
the_app = this;
}
@Override
protected void onResume()
{
super.onResume();
}
protected void onStop()
{
super.onStop();
simulator.stop_simu();
this.finish();
}
private class btn_listener implements OnClickListener
{
public void onClick(View v)
{
// Perform action on clicks
if (togglebutton.isChecked())
{
IP_address = ip_text.getText().toString();
simulator = new Main_thread(the_app, view, sm, IP_address);
the_sensors = simulator.the_sensors;
sm.registerListener(the_sensors,
SensorManager.SENSOR_ORIENTATION |SensorManager.SENSOR_ACCELEROMETER,
SensorManager.SENSOR_DELAY_UI);
simulator.start();
Toast.makeText(Android_Activity.this, "Start streaming" + IP_address, Toast.LENGTH_SHORT).show();
} else
{
simulator.stop_simu();
sm.unregisterListener(the_sensors);
Toast.makeText(Android_Activity.this, "Stop streaming", Toast.LENGTH_SHORT).show();
}
}
}
}
Main Thread
package carl.IOIO_car;
import android.hardware.SensorManager;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class Main_thread extends Thread
{
SurfaceView parent_context;
SensorManager mSensorManager = null;
Cam_thread the_cam;
Sensors_thread the_sensors;
IOIO_Thread ioio_thread_;
String ip_address;
Android_Activity the_app;
public Main_thread(Android_Activity app, SurfaceView v, SensorManager m, String ip)
{
super();
parent_context = v;
mSensorManager = m;
ip_address = ip;
the_app = app;
Log.e("Debug Main", "IP is " + ip_address);
the_cam = new Cam_thread(parent_context,ip_address);
the_sensors = new Sensors_thread(mSensorManager,ip_address);
ioio_thread_ = new IOIO_Thread(the_app, ip_address);
}
public void run()
{
//ioio_thread_.start();
the_cam.start_thread();
}
public void stop_simu()
{
the_cam.stop_thread();
the_sensors.stop_thread();
//ioio_thread_.abort();
}
}
Cam_Thread
package carl.IOIO_car;
import java.io.ByteArrayOutputStream;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.List;
import android.graphics.Bitmap;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.util.Log;
import android.view.SurfaceView;
public class Cam_thread
{
Camera mCamera;
public static int HEADER_SIZE = 5;
public static int DATAGRAM_MAX_SIZE = 1450 - HEADER_SIZE;
int frame_nb = 0;
int size_packet_sent = 0;
InetAddress serverAddr;
DatagramSocket socket;
Bitmap mBitmap;
int[] mRGBData;
int width_ima, height_ima;
private static final String TAG = "IP_cam";
SurfaceView parent_context;
private boolean STOP_THREAD;
String ip_address;
public Cam_thread(SurfaceView context, String ip)
{
parent_context = context;
ip_address = ip;
}
private void init()
{
try
{
serverAddr = InetAddress.getByName(ip_address);
socket = new DatagramSocket();
if (mCamera!=null){
Log.e(TAG, "Nulling camera");
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.release();
mCamera=null;
}
if(mCamera == null){
mCamera = Camera.open();
Log.e(TAG, "Setting up camera");
Camera.Parameters parameters = mCamera.getParameters();
//get a list of supported preview sizes and assign one
List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
Camera.Size previewSize = previewSizes.get(0);
parameters.setPreviewSize(previewSize.width, previewSize.height);
//Set Frame rate
parameters.setPreviewFrameRate(30);
//Set Scene
List<String> modes = parameters.getSupportedSceneModes();
parameters.setSceneMode(modes.get(0));
//Set focus mode
List<String> focus = parameters.getSupportedFocusModes();
parameters.setFocusMode(focus.get(0));
//Apply parameters to camera object
mCamera.setParameters(parameters);
//Provide a surface
if(parent_context.getHolder()==null)
Log.e(TAG, "Its a null holder");
Log.e("Debug", "Before");
mCamera.setPreviewDisplay(parent_context.getHolder());
Log.e("Debug", "After");
//Sets a call when preview data is available
mCamera.setPreviewCallback(new cam_PreviewCallback());
Log.e(TAG, "Camera configured");
//Start the preview
Log.e(TAG, "Starting preview");
mCamera.startPreview();
/*
parameters.setPreviewSize(320, 240);
parameters.setPreviewFrameRate(30);
parameters.setSceneMode(Camera.Parameters.SCENE_MODE_SPORTS);
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
parameters.setColorEffect(Camera.Parameters.EFFECT_NONE);
mCamera.setParameters(parameters);
mCamera.setPreviewDisplay(parent_context.getHolder());
mCamera.setPreviewCallback(new cam_PreviewCallback());
Log.e(TAG, "Starting preview");
mCamera.startPreview();
*/
}
}
catch (Exception exception)
{
Log.e(TAG, "Error: ", exception);
}
}
public void start_thread()
{
Log.e("Cam", "Started the Cam thread");
init();
}
public void stop_thread()
{
STOP_THREAD = true;
if (mCamera!=null){
mCamera.stopPreview();
mCamera.release();
mCamera=null;
}
socket.close();
}
public void send_data_UDP()
{
Log.e(TAG, "Started sending cam data");
if(mBitmap != null)
{
int size_p=0,i;
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.JPEG, 50, byteStream); // !!!!!!! change compression rate to change packets size
byte data[] = byteStream.toByteArray();
Log.e(TAG, "SIZE: " + data.length);
int nb_packets = (int) Math.ceil(data.length / (float)DATAGRAM_MAX_SIZE);
int size = DATAGRAM_MAX_SIZE;
/* Loop through slices */
for(i = 0; i < nb_packets; i++)
{
if(i >0 && i == nb_packets-1) size = data.length - i * DATAGRAM_MAX_SIZE;
/* Set additional header */
byte[] data2 = new byte[HEADER_SIZE + size];
data2[0] = (byte)frame_nb;
data2[1] = (byte)nb_packets;
data2[2] = (byte)i;
data2[3] = (byte)(size >> 8);
data2[4] = (byte)size;
/* Copy current slice to byte array */
System.arraycopy(data, i * DATAGRAM_MAX_SIZE, data2, HEADER_SIZE, size);
try
{
size_p = data2.length;
DatagramPacket packet = new DatagramPacket(data2, size_p, serverAddr, 9000);
socket.send(packet);
Log.e(TAG, "Sent a cam frame!");
} catch (Exception e) { Log.e(TAG, "Error: ", e);}
}
frame_nb++;
if(frame_nb == 128) frame_nb=0;
}
}
/* function converting image to RGB format taken from project: ViewfinderEE368
* http://www.stanford.edu/class/ee368/Android/ViewfinderEE368/
*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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);
}
}
}
// Preview callback used whenever new frame is available...send image via UDP !!!
private class cam_PreviewCallback implements PreviewCallback
{
@Override
public void onPreviewFrame(byte[] data, Camera camera)
{
if(STOP_THREAD == true)
{
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
mCamera.release();
mCamera = null;
return;
}
if (mBitmap == null) //create Bitmap image first time
{
Camera.Parameters params = camera.getParameters();
width_ima = params.getPreviewSize().width;
height_ima = params.getPreviewSize().height;
mBitmap = Bitmap.createBitmap(width_ima, height_ima, Bitmap.Config.RGB_565);
mRGBData = new int[width_ima * height_ima];
}
decodeYUV420SP(mRGBData, data, width_ima, height_ima);
mBitmap.setPixels(mRGBData, 0, width_ima, 0, 0, width_ima, height_ima);
send_data_UDP();
}
}
}
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="carl.IOIO_car"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<application android:icon="@drawable/icon" android:debuggable="true" android:label="@string/app_name">
<activity android:name="carl.IOIO_car.Android_Activity"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.UPDATE_DEVICE_STATS"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
</manifest>
This original code was written by Dr. Oros. http://www.cogsci.uci.edu/~noros/android_car.html
05-22 11:27:24.977 16750-16750/com.egomez.facedetection I/CameraActivity﹕ Switching Camera 05-22 11:27:25.219 16750-16750/com.egomez.facedetection D/Camera﹕ app passed NULL surface
To get rid of that error I had to get holder of SurfaceView (on the scenario I was attempting to fix was Switching from front camera to back camera and viceversa).
public void switchCamera(){
Log.i(TAG, "Switching Camera");
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
//mCamera = null;
}
//swap the id of the camera to be used
if (camId == Camera.CameraInfo.CAMERA_FACING_BACK) {
camId = Camera.CameraInfo.CAMERA_FACING_FRONT;
}else {
camId = Camera.CameraInfo.CAMERA_FACING_BACK;
}
try {
mCamera = Camera.open(camId);
//mCamera.setDisplayOrientation(90);
//You must get the holder of SurfaceView!!!
mCamera.setPreviewDisplay(mView.getHolder());
//Then resume preview...
mCamera.startPreview();
}
catch (Exception e) { e.printStackTrace(); }
}
Hope it helps for anyone running into similar issue.
Thats not true. Just set up a small delay with a Handler and it works fine on Nexus too.
Just had the problem myself with black Pictures on those devices but with 1sec of delay everything works fine
All camera things and stuff must be created from Activity for example OnCreate or something, signal for take photo can be pushed from different context.
来源：https://stackoverflow.com/questions/12098298/android-camera-app-passed-null-surface