database connect in php

Example (MySQLi Object-Oriented)

<?php
$servername = "localhost";
$username = "username";
$password = "password";

$conn = new mysqli($servername, $username, $password);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>

Example (MySQLi Procedural)

<?php
$servername = "localhost";
$username = "username";
$password = "password";

$conn = mysqli_connect($servername, $username, $password);

if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
?>

Example (PDO)

<?php
$servername = "localhost";
$username = "username";
$password = "password";

try {
    $conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
   
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully";
    }
catch(PDOException $e)
    {
    echo "Connection failed: " . $e->getMessage();
    }
?>

how to get facebook profile in andriod

public class FacebookInfo extends Activity {
...
String get_id, get_name, get_gender, get_email, get_birthday, get_locale, get_location;

private Session.StatusCallback fbStatusCallback = new Session.StatusCallback() {
    public void call(Session session, SessionState state, Exception exception) {
        if (state.isOpened()) {
            Request.executeMeRequestAsync(session, new Request.GraphUserCallback() {
                public void onCompleted(GraphUser user, Response response) {
                    if (response != null) {
                        // do something with <response> now
                        try{
                            get_id = user.getId();
                            get_name = user.getName();
                            get_gender = (String) user.getProperty("gender");
                            get_email = (String) user.getProperty("email");
                            get_birthday = user.getBirthday();
                            get_locale = (String) user.getProperty("locale");
                            get_location = user.getLocation().toString();  

                        Log.d(LOG_TAG, user.getId() + "; " + 
                            user.getName() + "; " +
                            (String) user.getProperty("gender") + "; " +       
                            (String) user.getProperty("email") + "; " +
                            user.getBirthday()+ "; " +
                            (String) user.getProperty("locale") + "; " +
                            user.getLocation());
                        } catch(Exception e) {
                             e.printStackTrace();
                             Log.d(LOG_TAG, "Exception e");
                         }

                    }
                }
            });
        }
    }
};
...
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fbinfo);
    try {
        openActiveSession(this, true, fbStatusCallback, Arrays.asList(
                new String[] { "email",  "user_location", "user_birthday",
 "user_likes", "publish_actions" }), savedInstanceState);
    }
    catch (Exception e) {
        e.printStackTrace();
    }
  private  Session openActiveSession(Activity activity, boolean allowLoginUI,
 StatusCallback callback, List<String> permissions, Bundle savedInstanceState) {
    OpenRequest openRequest = new OpenRequest(activity).
setPermissions(permissions).setLoginBehavior(SessionLoginBehavior.
SSO_WITH_FALLBACK).setCallback(callback).
setDefaultAudience(SessionDefaultAudience.FRIENDS);

    Session session = Session.getActiveSession();
    Log.d(LOG_TAG, "" + session);
    if (session == null) {
        Log.d(LOG_TAG, "" + savedInstanceState);
        if (savedInstanceState != null) {
            session = Session.restoreSession(this, null, fbStatusCallback, savedInstanceState);
        }
        if (session == null) {
            session = new Session(this);
        }
        Session.setActiveSession(session);
        if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED) || allowLoginUI) {
            session.openForRead(openRequest);
            return session;
        }
    }
    return null;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
}
}

how to create carousel view in android

MainActivity.java

public class MainActivity extends FragmentActivity {

    public final static int LOOPS = 1000;
    public static int FIRST_PAGE; // = count * LOOPS / 2;
    public final static float BIG_SCALE = 1.0f;
    public final static float SMALL_SCALE = 0.7f;
    public final static float DIFF_SCALE = BIG_SCALE - SMALL_SCALE;
    public MyPagerAdapter adapter;
    public static ViewPager pager;
    /*** variables for the View */
    public int coverUrl[];
    public int img_id[] =new int[] {0,1,2,3,4,5,6};
    public static int count;

    public static MainActivity mainActivityCtx;

    public static int currentPage = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        coverUrl = new int[] { R.drawable.images_one, R.drawable.images_two,R.drawable.images_three,R.drawable.images_for,R.drawable.images_fiv,R.drawable.images_six,R.drawable.images_seven, };

        mainActivityCtx = this;
        pager = (ViewPager) findViewById(R.id.myviewpager);
        count = coverUrl.length;
        DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        int pageMargin = 0;
        pageMargin = (int) ((metrics.widthPixels / 4) * 2);
        pager.setPageMargin(-pageMargin);

        try {
            adapter = new MyPagerAdapter(this, this.getSupportFragmentManager());
            pager.setAdapter(adapter);
            adapter.notifyDataSetChanged();

            //FIRST_PAGE = count * LOOPS / 2;

            pager.setOnPageChangeListener(adapter);
            // Set current item to the middle page so we can fling to both
            // directions left and right
            pager.setCurrentItem(FIRST_PAGE); // FIRST_PAGE
            // pager.setFocusableInTouchMode(true);
            pager.setOffscreenPageLimit(3);
            // Set margin for pages as a negative number, so a part of next and
            // previous pages will be showed

        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }
}

MyFragment.java

public class MyFragment extends Fragment {
    public static Fragment newInstance(MainActivity context, int pos,
            float scale) {
        Bundle b = new Bundle();
        b.putInt("pos", pos);
        b.putFloat("scale", scale);
        return Fragment.instantiate(context, MyFragment.class.getName(), b);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        if (container == null) {
            return null;
        }

        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(400, 400);
        LinearLayout fragmentLL = (LinearLayout) inflater.inflate(R.layout.main_fragment,
                container, false);
        final int pos = this.getArguments().getInt("pos");
        //TextView tv = (TextView) fragmentLL.findViewById(R.id.text);

        //tv.setText("Image " + pos);

        final ImageView iv = (ImageView) fragmentLL.findViewById(R.id.pagerImg);
       
        iv.setLayoutParams(layoutParams);
        iv.setImageResource(MainActivity.mainActivityCtx.coverUrl[pos]);
        iv.setId(MainActivity.mainActivityCtx.img_id[pos]);
        iv.setPadding(15, 15, 15, 15);

        MyLinearLayout root = (MyLinearLayout) fragmentLL.findViewById(R.id.root);
        float scale = this.getArguments().getFloat("scale");
        root.setScaleBoth(scale);

        return fragmentLL;
    }
}

MyLinearLayout.java

public class MyLinearLayout extends LinearLayout {
    private float scale = MainActivity.BIG_SCALE;

    public MyLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyLinearLayout(Context context) {
        super(context);
    }

    public void setScaleBoth(float scale) {
        this.scale = scale;
        this.invalidate();

    }

    @Override
    protected void onDraw(Canvas canvas) {
        // The main mechanism to display scale animation, you can customize it
        // as your needs
        int w = this.getWidth();
        int h = this.getHeight();
        canvas.scale(scale, scale, w / 2, h / 2);

        super.onDraw(canvas);
    }

}

MyPagerAdapter.java

public class MyPagerAdapter extends FragmentPagerAdapter implements
        ViewPager.OnPageChangeListener {

    private MyLinearLayout cur = null;
    private MyLinearLayout next = null;
    private MainActivity context;
    private FragmentManager fm;
    private float scale;
    int pCount = 0;

    public MyPagerAdapter(MainActivity context, FragmentManager fm) {
        super(fm);
        this.fm = fm;
        this.context = context;
    }

    @Override
    public Fragment getItem(int position) {
        // make the first pager bigger than others
        try {
            if (position == MainActivity.FIRST_PAGE)
                scale = MainActivity.BIG_SCALE;
            else
                scale = MainActivity.SMALL_SCALE;

            position = position % MainActivity.count;

        } catch (Exception e) {
            // TODO: handle exception
        }
        return MyFragment.newInstance(context, position, scale);
    }

    @Override
    public int getCount() {
        int count = 0;
        try {
            count = 4 ;//MainActivity.count * MainActivity.LOOPS;
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        return count;
    }

    @Override
    public void onPageScrolled(int position, float positionOffset,
            int positionOffsetPixels) {
        try {
            if (positionOffset >= 0f && positionOffset <= 1f) {
                cur = getRootView(position);
                next = getRootView(position + 1);

                cur.setScaleBoth(MainActivity.BIG_SCALE- MainActivity.DIFF_SCALE * positionOffset);
                next.setScaleBoth(MainActivity.SMALL_SCALE+ MainActivity.DIFF_SCALE * positionOffset);

                pCount++;
            }
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }

    @Override
    public void onPageSelected(int position) {
       
        //System.out.println("!!!!!!!!!!!"+position);
       
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }

    private MyLinearLayout getRootView(int position) {
        return (MyLinearLayout) fm
                .findFragmentByTag(this.getFragmentTag(position)).getView()
                .findViewById(R.id.root);
    }

    private String getFragmentTag(int position) {
        return "android:switcher:" + context.pager.getId() + ":" + position;
    }
}

activity.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    android:orientation="vertical" >

    <android.support.v4.view.ViewPager
        android:id="@+id/myviewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center"
        android:layout_marginLeft="0dp"
        android:layout_marginRight="0dp"
        android:overScrollMode="never" />

</LinearLayout>

main_freagment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical" >

    <com.your.MyLinearLayout
        android:id="@+id/root"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:gravity="center"
        android:orientation="vertical" >

        <ImageView
            android:id="@+id/pagerImg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:src="@drawable/ic_launcher" />

         </com.your.MyLinearLayout>

</LinearLayout>

how to use gesture detector in android

 Left & Right Touch Event

final GestureDetector gesture = new GestureDetector(getApplicationContext(),
                new GestureDetector.SimpleOnGestureListener() {

                    @Override
                    public boolean onDown(MotionEvent e) {
                        return true;
                    }

                    @Override
                    public boolean onFling(MotionEvent e1, MotionEvent e2,
                            float velocityX, float velocityY) {
                        final int SWIPE_MIN_DISTANCE = 120;
                        final int SWIPE_MAX_OFF_PATH = 250;
                        final int SWIPE_THRESHOLD_VELOCITY = 200;
                        try {
                            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                                return false;
                            if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
                                    && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                               
                                System.out.println("Left");
                               
                            } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
                                    && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {

                                System.out.println("Right");
                               
                            }
                        } catch (Exception e) {
                            // nothing
                        }
                        return super.onFling(e1, e2, velocityX, velocityY);
                    }
                });

        layout.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return gesture.onTouchEvent(event);
            }
        });

how to create custom camera in android example

Detecting camera hardware

private boolean checkCameraHardware(Context context) {
    if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
    
        return true;
    } else {
     
        return false;
    }
}

Accessing cameras


public static Camera getCameraInstance(){
    Camera c = null;
    try {
        c = Camera.open();
    }
    catch (Exception e){
      
    }
    return c;
}


Creating a preview class

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;

       
        mHolder = getHolder();
        mHolder.addCallback(this);
       
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

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

    public void surfaceDestroyed(SurfaceHolder holder) {
       
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
     
        if (mHolder.getSurface() == null){
        
          return;
        }
        try {
            mCamera.stopPreview();
        } catch (Exception e){
         
        }

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

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

preview in a layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
  <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"/>
</LinearLayout>

 Creating a CameraActivity class.

public class CameraActivity extends Activity {

    private Camera mCamera;
    private CameraPreview mPreview;
    private Camera mCamera;
    private SurfaceView mPreview;
    private MediaRecorder mMediaRecorder;
    public static final int MEDIA_TYPE_IMAGE = 1;
    public static final int MEDIA_TYPE_VIDEO = 2;
    private boolean isRecording = false;

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

        // Create an instance of Camera
        mCamera = getCameraInstance();

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


    Button captureButton = (Button) findViewById(id.button_capture);
    captureButton.setOnClickListener(
        new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               
                mCamera.takePicture(null, null, mPicture);

            }
        });

Button captureButton = (Button) findViewById(id.button_capture);
captureButton.setOnClickListener(
    new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (isRecording) {
               
                mMediaRecorder.stop();
                releaseMediaRecorder();
                mCamera.lock();        

             
                setCaptureButtonText("Capture");
                isRecording = false;
            } else {
               
                if (prepareVideoRecorder()) {
                  
                    mMediaRecorder.start();

                   
                    setCaptureButtonText("Stop");
                    isRecording = true;
                } else {
                 
                    releaseMediaRecorder();
                   
                }
            }
        }
    });
 }

private 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: " +
                e.getMessage());
            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());
        }
    }
  };

private boolean prepareVideoRecorder(){
    mMediaRecorder = new MediaRecorder();
  
    mCamera.unlock();
    mMediaRecorder.setCamera(mCamera);
  
    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);    
    mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);       
    mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
    mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());
    mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());

    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;
}

private static Uri getOutputMediaFileUri(int type){
      return Uri.fromFile(getOutputMediaFile(type));
}

private static File getOutputMediaFile(int type){
  
    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_PICTURES), "MyCameraApp");
   
  
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }
  
    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;
}

@Override
    protected void onPause() {
        super.onPause();
        releaseMediaRecorder();      
        releaseCamera();             
    }

    private void releaseMediaRecorder(){
        if (mMediaRecorder != null) {
            mMediaRecorder.reset();  
            mMediaRecorder.release();
            mMediaRecorder = null;
            mCamera.lock();          
        }
    }

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

how to open camera using camera intent in android

private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;
private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 200;

private Uri fileUri;


// CAPTURE IMAGE intent
   Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
   fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
   intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
   startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

//CAPTURE VIDEO Intent
  Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
  fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);
  intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
  intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
  startActivityForResult(intent, CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE);

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {
        if (resultCode == RESULT_OK) {
         
            Toast.makeText(this, "Image saved to:\n" +
                     data.getData(), Toast.LENGTH_LONG).show();
        } else if (resultCode == RESULT_CANCELED) {
          
        } else {
           
        }
    }

    if (requestCode == CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE) {
        if (resultCode == RESULT_OK) {
          
            Toast.makeText(this, "Video saved to:\n" +
                     data.getData(), Toast.LENGTH_LONG).show();
        } else if (resultCode == RESULT_CANCELED) {
           
        } else {
         
        }
    }
}

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera" android:required="false" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />

how to scan barcode in android example

//call intent your scan button

Intent intent = new Intent(TrackingActivity.this,CameraTestActivity.class);
startActivity(intent);

//add this CameraPreview

CameraPreview.java

import java.io.IOException;

import android.app.Activity;
import android.os.Bundle;

import android.util.Log;

import android.view.View;
import android.view.Surface;
import android.view.SurfaceView;
import android.view.SurfaceHolder;

import android.content.Context;

import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.Parameters;

/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private PreviewCallback previewCallback;
    private AutoFocusCallback autoFocusCallback;

    public CameraPreview(Context context, Camera camera,
                         PreviewCallback previewCb,
                         AutoFocusCallback autoFocusCb) {
        super(context);
        mCamera = camera;
        previewCallback = previewCb;
        autoFocusCallback = autoFocusCb;

        /*
         * Set camera to continuous focus if supported, otherwise use
         * software auto-focus. Only works for API level >=9.
         */
        /*
        Camera.Parameters parameters = camera.getParameters();
        for (String f : parameters.getSupportedFocusModes()) {
            if (f == Parameters.FOCUS_MODE_CONTINUOUS_PICTURE) {
                mCamera.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
                autoFocusCallback = null;
                break;
            }
        }
        */

        // 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);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            mCamera.setPreviewDisplay(holder);
        } catch (IOException e) {
            Log.d("DBG", "Error setting camera preview: " + e.getMessage());
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Camera preview released in activity
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        /*
         * 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
        }

        try {
            // Hard code camera surface rotation 90 degs to match Activity view in portrait
            mCamera.setDisplayOrientation(90);

            mCamera.setPreviewDisplay(mHolder);
            mCamera.setPreviewCallback(previewCallback);
            mCamera.startPreview();
            mCamera.autoFocus(autoFocusCallback);
        } catch (Exception e){
            Log.d("DBG", "Error starting camera preview: " + e.getMessage());
        }
    }
}

CameraTestActivity.java

import net.sourceforge.zbar.Config;
import net.sourceforge.zbar.Image;
import net.sourceforge.zbar.ImageScanner;
import net.sourceforge.zbar.Symbol;
import net.sourceforge.zbar.SymbolSet;
import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.PreviewCallback;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.TextView;


/* Import ZBar Class files */

public class CameraTestActivity extends Activity
{
    private Camera mCamera;
    private CameraPreview mPreview;
    private Handler autoFocusHandler;

//    TextView scanText;
//    Button scanButton;

    ImageScanner scanner;
   
    private boolean barcodeScanned = false;
    private boolean previewing = true;

    static {
        System.loadLibrary("iconv");
    }

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

        autoFocusHandler = new Handler();
        mCamera = getCameraInstance();

        /* Instance barcode scanner */
        scanner = new ImageScanner();
        scanner.setConfig(0, Config.X_DENSITY, 3);
        scanner.setConfig(0, Config.Y_DENSITY, 3);

        mPreview = new CameraPreview(this, mCamera, previewCb, autoFocusCB);
        FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview);
        preview.addView(mPreview);

//        scanText = (TextView)findViewById(R.id.scanText);

//       scanButton = (Button)findViewById(R.id.ScanButton);

//       scanButton.setOnClickListener(new OnClickListener() {
//               public void onClick(View v) {
                    if (barcodeScanned) {
                        barcodeScanned = false;
//                       scanText.setText("Scanning...");
                        mCamera.setPreviewCallback(previewCb);
                        mCamera.startPreview();
                        previewing = true;
                        mCamera.autoFocus(autoFocusCB);
                    }
//                }
//          });
    }

    public void onPause() {
        super.onPause();
        releaseCamera();
    }

    /** A safe way to get an instance of the Camera object. */
    public static Camera getCameraInstance(){
        Camera c = null;
        try {
            c = Camera.open();
        } catch (Exception e){
        }
        return c;
    }

    private void releaseCamera() {
        if (mCamera != null) {
            previewing = false;
            mCamera.setPreviewCallback(null);
            mCamera.release();
            mCamera = null;
        }
    }

    private Runnable doAutoFocus = new Runnable() {
            public void run() {
                if (previewing)
                    mCamera.autoFocus(autoFocusCB);
            }
        };

    PreviewCallback previewCb = new PreviewCallback() {
            public void onPreviewFrame(byte[] data, Camera camera) {
                Camera.Parameters parameters = camera.getParameters();
                Size size = parameters.getPreviewSize();

                Image barcode = new Image(size.width, size.height, "Y800");
                barcode.setData(data);

                int result = scanner.scanImage(barcode);
                Datalist.result = result;
               
                if (result != 0) {
                    previewing = false;
                    mCamera.setPreviewCallback(null);
                    mCamera.stopPreview();
                   
                    SymbolSet syms = scanner.getResults();
                    for (Symbol sym : syms) {
//                        scanText.setText("barcode result " + sym.getData());
                        Datalist.barcode_result = sym.getData();
                        barcodeScanned = true;
                       
                    }
                    onBackPressed();
                }
            }
        };

    // Mimic continuous auto-focusing
    AutoFocusCallback autoFocusCB = new AutoFocusCallback() {
            public void onAutoFocus(boolean success, Camera camera) {
                autoFocusHandler.postDelayed(doAutoFocus, 1000);
            }
        };
}

//add permission

AndroidManifest

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

// libray

https://github.com/dm77/ZBarScanner