using internal camera through SurfaceView

Question

I am using internal camera through SurfaceView. but I have problem when I press Home Button and restart. I find a lot similar Questions. and I try many method but they can not fix. Maybe I miss something, So please help me. thanks I try method below list that can't fix NullPointerException 1. thread method (it doesn't work)

the LogCat show

D/AndroidRuntime(571): Shutting down VM
W/dalvikvm(571): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
E/AndroidRuntime(571): FATAL EXCEPTION: main
E/AndroidRuntime(571): java.lang.NullPointerException
E/AndroidRuntime(571): at com.exampl.cameraexample.Preview.surfaceCreated(Preview.java:56)
E/AndroidRuntime(571): at android.view.SurfaceView.updateWindow(SurfaceView.java:562)
E/AndroidRuntime(571): at android.view.SurfaceView.access$000(SurfaceView.java:82)
E/AndroidRuntime(571): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:171)
E/AndroidRuntime(571): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:590)
E/AndroidRuntime(571): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1596)
E/AndroidRuntime(571): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2418)
E/AndroidRuntime(571): at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(571): at android.os.Looper.loop(Looper.java:137)
E/AndroidRuntime(571): at android.app.ActivityThread.main(ActivityThread.java:4340)
E/AndroidRuntime(571): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(571): at java.lang.reflect.Method.invoke(Method.java:511)
E/AndroidRuntime(571): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) E/AndroidRuntime(571): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
E/AndroidRuntime(571): at dalvik.system.NativeStart.main(Native Method)

this is Mainactivity

package com.example.cameraexample;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Date;
import java.text.SimpleDateFormat;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.res.Configuration;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;

public class MainActivity extends Activity {
private static final String TAG = "CameraDemo";
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;

private Camera mCamera;
private Preview mPreview;
//Button captureButton;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setRequestedOrientation(1);

    //if (checkCameraHardware(this)) {
 // Create an instance of Camera
    //mCamera = getCameraInstance();
   // }

 // Create our Preview view and set it as the content of our activity.
   // mPreview = new Preview(this, mCamera);
   // FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
   // preview.addView(mPreview);

    // Add a listener to the Capture button
    Button captureButton = (Button) findViewById(R.id.button_capture);
    captureButton.setOnClickListener(
        new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // get an image from the camera
                mCamera.takePicture(null, null, mPicture);
            }
        }
    );
    Log.d(TAG, "onCreate");
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
  // TODO Auto-generated method stub
  super.onConfigurationChanged(newConfig);
  Log.d(TAG, "onConfigurationChanged");

}


/** A safe way to get an instance of the Camera object. */
public static Camera getCameraInstance(){
    Camera c = null;
    try {
        c = Camera.open(); // attempt to get a Camera instance
        Log.d(TAG, "OPEN Camera!!!");
    }
    catch (Exception e){
        // Camera is not available (in use or does not exist)
        Log.d(TAG, "NULL Camera");
    }
    Log.d(TAG, "OPEN Camera");
    return c; // returns null if camera is unavailable

}

PictureCallback mPicture = new PictureCallback() {
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
        if (pictureFile == null){
            Log.d(TAG, "Error creating media file, check storage permissions: ");
            return;
            }

        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
        } catch (FileNotFoundException e) {
            Log.d(TAG, "File not found: " + e.getMessage());
        } catch (IOException e) {
            Log.d(TAG, "Error accessing file: " + e.getMessage());
        }
        mCamera.startPreview();

        Log.d(TAG, "onPictureTaken");
    }
};

/** Create a File for saving an image or video */
@SuppressLint("SimpleDateFormat")
private static File getOutputMediaFile(int type){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_PICTURES), "MyCameraApp");
    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }

    // Create a media file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date(type));
    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;
}

@Override
protected void onDestroy() {
 // TODO Auto-generated method stub
 super.onDestroy();
 Toast.makeText(this, "onDestroy", Toast.LENGTH_LONG).show();
 Log.d(TAG, "onDestroy");
}

@Override
protected void onPause() {
    super.onPause();
    Toast.makeText(this, "onPause", Toast.LENGTH_LONG).show();
    releaseCamera();              // release the camera immediately on pause event
    Log.d(TAG, "onPause");
}

@Override
protected void onRestart() {
 // TODO Auto-generated method stub
 super.onRestart();
 Toast.makeText(this, "onRestart", Toast.LENGTH_LONG).show();
 Log.d(TAG, "onRestart");
}

@Override
protected void onResume() {
 // TODO Auto-generated method stub
 super.onResume();
 //if (checkCameraHardware(this)) {
 // Create an instance of Camera
    mCamera = getCameraInstance();
   // }

 // Create our Preview view and set it as the content of our activity.
    mPreview = new Preview(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(mPreview);   
 Toast.makeText(this, "onResume", Toast.LENGTH_LONG).show();
 Log.d(TAG, "onResume");

}

@Override
protected void onStart() {
 // TODO Auto-generated method stub
 super.onStart();
 Toast.makeText(this, "onStart", Toast.LENGTH_LONG).show();
 Log.d(TAG, "onStart");
}

@Override
protected void onStop() {
 // TODO Auto-generated method stub
 super.onStop();
 Toast.makeText(this, "onStop", Toast.LENGTH_LONG).show();
 Log.d(TAG, "onStop");
}

private void releaseCamera(){
    if (mCamera != null){
        mCamera.release();        // release the camera for other applications
        mCamera = null;
    }
}


}

the other preview.java

package com.example.cameraexample;

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.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;

public class Preview extends SurfaceView implements SurfaceHolder.Callback, Runnable {
private static final String TAG = "Preview";

private Thread thread;
private boolean running;
private SurfaceHolder mHolder;
private Camera mCamera;

@SuppressWarnings("deprecation")
public Preview(Context context, Camera camera) {
    super(context);
    mCamera = camera;
    if(camera==null){

        Log.e("Camera","my camera is null...");

        }
    // Install a SurfaceHolder.Callback so we get notified when the
    // underlying surface is created and destroyed.
    mHolder = getHolder();
    mHolder.addCallback(this);
    // deprecated setting, but required on Android versions prior to 3.0
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    Log.d(TAG, "Preview");
}

public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, now tell the camera where to draw the preview.


    try {
        Log.d(TAG, "surfaceCreated STARTED");
        running = true;
        thread = new Thread(this, "himi_Thread_one");
        thread.start();

        mCamera.setPreviewDisplay(holder);
        mCamera.setDisplayOrientation(90);
        mCamera.startPreview();
    } catch (IOException e) {
        Log.d(TAG, "Error setting camera preview: " + e.getMessage());
    }
    Log.d(TAG, "surfaceCreated");
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // empty. Take care of releasing the Camera preview in your activity.
     running = false;
    Log.d(TAG, "surfaceDestroyed");
}

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.

    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.setDisplayOrientation(90);
        mCamera.startPreview();

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


public void run() {
    while (running) {
        try {
            Thread.sleep(100);
        } catch (Exception ex) {
        }
    }
    Log.d(TAG, "RUN");
}
}

and AndoridMainfest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.cameraexample"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.CHANGE_CONFIGURATION"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />  
<uses-feature android:name="android.hardware.camera.autofocus" /> 
<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity

        android:name="com.example.cameraexample.MainActivity"
        android:label="@string/app_name" 
        android:configChanges="orientation|keyboard|keyboardHidden|screenSize">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

the layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
/>

<Button
android:id="@+id/button_capture"
android:text="Capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>

</RelativeLayout>

Answer 1

Finally, I got the solution fix this problem.

revise releaseCamera()

private void releaseCamera(){
    if (mCamera != null){   
        mPreview.getHolder().removeCallback(mPreview);
        mCamera.release();        // release the camera for other applications
        mCamera = null;
    }
}

YES!!! when I press the HOME button then restart. there is no crash.