nullpointer exception raises when i click on the button

Question

When I click on CheckData button on android, it is throwing a nullpointer exception.

SaveData.java

public class SaveData extends Activity implements OnClickListener {     
    static final int DIALOG_ID = 0;

    private Uri mImageCaptureUri;
    private ImageView mImageView;   
    public static class Certificates {
    private Bitmap bmp;

        public Certificates(Bitmap b) {
        bmp = b;
        }
        public Bitmap getBitmap() { return bmp; }
    }

    private static final int PICK_FROM_CAMERA = 1;
    private static final int PICK_FROM_FILE = 2;

    @Override
        protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.addname);

        View button1Click=findViewById(R.id.btn_choose);
        button1Click.setOnClickListener(this);
        View button2Click = findViewById(R.id.Button01add);
        button2Click.setOnClickListener(this);
        View button3Click = findViewById(R.id.Button01check);
        button3Click.setOnClickListener(this);  
    }

        public void onClick(View v){        
        switch(v.getId()){

        case R.id.Button01add:
            showDialog(DIALOG_ID);
            break;

        case R.id.Button01check:
            startActivity(new Intent (SaveData.this,CheckData.class));
            break;
        }

// picking an image from camera or gallery         
            final String [] items           = new String [] {"From Camera", "From SD Card"};                
            ArrayAdapter<String> adapter    = new ArrayAdapter<String> (this, android.R.layout.select_dialog_item,items);
            AlertDialog.Builder builder     = new AlertDialog.Builder(this);

            builder.setTitle("Select Image");
            builder.setAdapter( adapter, new DialogInterface.OnClickListener() {
                public void onClick( DialogInterface dialog, int item ) {
                    if (item == 0) {
                        Intent intent    = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                        File file        = new File(Environment.getExternalStorageDirectory(), "tmp_avatar_" + String.valueOf(System.currentTimeMillis()) + ".jpg");
                        mImageCaptureUri = Uri.fromFile(file);

                        try {           
                            intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, mImageCaptureUri);
                            intent.putExtra("return-data", true);                           
                            startActivityForResult(intent, PICK_FROM_CAMERA);
                    }   catch (Exception e) {
                            e.printStackTrace();
                        }           

                        dialog.cancel();
                    } else {
                        Intent intent = new Intent();

                        intent.setType("image/*");
                        intent.setAction(Intent.ACTION_GET_CONTENT);

                        startActivityForResult(Intent.createChooser(intent, "Complete action using"), PICK_FROM_FILE);
                    }
                }
            } );

            final AlertDialog dialog = builder.create();

            mImageView = (ImageView) findViewById(R.id.image1);

            ((Button) findViewById(R.id.btn_choose)).setOnClickListener(new View.OnClickListener() {            
                @Override
                public void onClick(View v) {
                    dialog.show();
                }
            });
        }

        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            if (resultCode != RESULT_OK) return;

            Bitmap bitmap   = null;
            String path     = "";

            if (requestCode == PICK_FROM_FILE) {
                mImageCaptureUri = data.getData(); 
                path = getRealPathFromURI(mImageCaptureUri); //from Gallery 

                if (path == null)
                    path = mImageCaptureUri.getPath(); //from File Manager

                if (path != null) 
                    bitmap  = BitmapFactory.decodeFile(path);
            } else {
                path    = mImageCaptureUri.getPath();
                bitmap  = BitmapFactory.decodeFile(path);
            }

            mImageView.setImageBitmap(bitmap);      
        }

        public String getRealPathFromURI(Uri contentUri) {
            String [] proj      = {MediaStore.Images.Media.DATA};
            Cursor cursor       = managedQuery( contentUri, proj, null, null,null);

            if (cursor == null) return null;

            int column_index    = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);

            cursor.moveToFirst();

            return cursor.getString(column_index);
        }

    protected final Dialog onCreateDialog(final int id) {
        Dialog dialog = null;
        switch(id) {
        case DIALOG_ID:
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setMessage("Information saved successfully ! Add Another Info?")
            .setCancelable(false)
            .setPositiveButton("No", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {

                    SaveData.this.finish();
              }
            })
        .setNegativeButton("Yes", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.cancel();
                }
            });
            AlertDialog alert = builder.create(); 
            dialog = alert;
            break;
        default:
        }
        return dialog;
    }
// menu option  
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.layout.mymenu, menu);        
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getItemId() == R.id.item1) {
            Log.d("Option", "Save option is clicked");           
        }
        if(item.getItemId() == R.id.item2) {
            Log.d("Option", "Delete option is clicked");
        }
        if(item.getItemId() == R.id.item3) {
            Log.d("Option", "Exit option is clicked");
        }       
        return super.onOptionsItemSelected(item);       
    }
}

DataManipulator.java:

public class DataManipulator {
public static final String KEY_IMG = "image";

 private DatabaseHelper mDbHelper;
    private SQLiteDatabase mDb;

    private static final String DATABASE_NAME = "DBtest";
    private static final int DATABASE_VERSION = 1;

    private static final String CERTIFICATES_TABLE = "certificates";

    private static final String CREATE_CERTIFICATES_TABLE = "create table "+CERTIFICATES_TABLE+" (" +KEY_IMG+" blob not null) ";

    private final Context mCtx;
    private static class DatabaseHelper extends SQLiteOpenHelper {
        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        public void onCreate(SQLiteDatabase db) {
            db.execSQL(CREATE_CERTIFICATES_TABLE);
        }

        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS "+CERTIFICATES_TABLE);
            onCreate(db);
        }
    }
    public void Reset() { mDbHelper.onUpgrade(this.mDb, 1, 1); }

    public DataManipulator(Context ctx) {
        mCtx = ctx;
        mDbHelper = new DatabaseHelper(mCtx);
    }

    public DataManipulator open() throws SQLException {
        mDb = mDbHelper.getWritableDatabase();
        return this;
    }

    public void close() { mDbHelper.close(); }

    public void createCertificatesEntry(Certificates certificates) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        certificates.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out);
        ContentValues cv = new ContentValues();
        cv.put(KEY_IMG, out.toByteArray());
        mDb.insert(CERTIFICATES_TABLE,  null, cv);
    }
    public Certificates getFirstCertificatesFromDB() throws SQLException {
        Cursor cur = mDb.query(true, CERTIFICATES_TABLE,  new String[] {KEY_IMG}, null, null, null, null, null, null);
        if(cur.moveToFirst()) {
            byte[] blob = cur.getBlob(cur.getColumnIndex(KEY_IMG));
            ByteArrayInputStream inputStream = new ByteArrayInputStream(blob);
            Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
            cur.close();
            return new Certificates(bitmap);
        }
        cur.close();
        return null;
    }    
}

DataManipulator.java:60 is certificates.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out);

CheckData.java:

    public class CheckData extends ListActivity  {     
    TextView selection;
    DataManipulator dm;
    private DataManipulator DataManipulator;

        protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.check);
        dm = new DataManipulator(this);

        LinearLayout layout = new LinearLayout(this);
        ImageView image = new ImageView(this);
        DataManipulator = new DataManipulator(this);

        Certificates testCertificates = new Certificates(BitmapFactory.decodeFile(Context.STORAGE_SERVICE));

        DataManipulator.open();
        DataManipulator.createCertificatesEntry( (Certificates) testCertificates);
        DataManipulator.close(); 

        testCertificates = null;

        DataManipulator.open();
        testCertificates = DataManipulator.getFirstCertificatesFromDB();
        DataManipulator.close();

        image.setImageBitmap(((Certificates) testCertificates).getBitmap());

        setContentView(layout);
    }
}

CheckData.java:29 is DataManipulator.createCertificatesEntry( (Certificates) testCertificates);

Logcat error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{list.certificates/list.certificates.CheckData}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
at android.app.ActivityThread.access$600(ActivityThread.java:122)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4340)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at list.certificates.DataManipulator.createCertificatesEntry(DataManipulator.java:60)
at list.certificates.CheckData.onCreate(CheckData.java:29)
at android.app.Activity.performCreate(Activity.java:4465)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)

certificates.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out); — Abhinai, Jun 28 '12 at 08:12

score 8 · Answer 1 · edited May 23 '17 at 12:23

8

You're getting a null from certificates.getBitmap() because there's not a bitmap there. In your initial assignment, you're trying to decode a file that doesn't exist. Using Context.STORAGE_SERVICE doesn't work that way, it's just a string equaling storage.

For example code of how to use a storage manager properly, try this.

If you're just trying to decode a resource(drawable, raw, etc) use another form of decode:

InputStream is = context.getResources().openRawResource(resID);
Bitmap bitmap = BitmapFactory.decodeStream(is);

Update: Assuming I know what it is you're trying to do, the problem is that you're switching to the CheckData activity without passing the selected bitmap in any way. The activity has no way of knowing what bitmap to use, and Context.STORAGE_SERVICE is not a bitmap in any way, so you can't decode it.

For good answers on how to pass the bitmap to the new activity, look here.

In short, you could add an mBitmap variable to SaveData, and pass it along to CheckData.

For this, change the code in SaveData.onClick() to:

case R.id.Button01check:
    Intent intent = new Intent (SaveData.this,CheckData.class);
    intent.putExtra("bitmapData", mBitmap)
    startActivity(intent);
    break;

And, in onActivityResult(), add this at the end:

mBitmap = bitmap;

In CheckData.onCreate():

Bitmap bmp = getIntent().getExtras().get("bitmapData");
if(bmp != null) {
    Certificates testCertificates = new Certificates(bmp);
} else {
    // Back out gracefully //
}

edited May 23 '17 at 12:23

Community

1
1

answered Jun 26 '12 at 18:24

Geobits

22,218
6
59
103

i would like to pick image from gallery or sdcard while picking it runs fine while clicking on checkdata its throwing an error as nullpointer exception – Abhinai Jun 27 '12 at 08:01
Did you put it at the end of `onActivityResult()` like I said? If so, `bitmap` _has_ to resolve, you're already using it on the last current line in that function. Put it directly after `mImageView.setImageBitmap(bitmap);` As for `mBitmap`, you need to declare it in the `SaveData` class with `Bitmap mBitmap;` – Geobits Jun 28 '12 at 08:20
yes i have added this mBitmap = bitmap; at here as protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode != RESULT_OK) { mBitmap = bitmap; return; } – Abhinai Jun 28 '12 at 08:34
What class did you put it in? You already have that function in the `SaveData` class, which is where it needs to go. Just put the one line at the end of the existing function, directly after the line I said. – Geobits Jun 28 '12 at 16:48
i texted only this line as mBitmap=bitmap; in onActivityResult but it is showing as it cannot be resolved – Abhinai Jun 29 '12 at 07:20

score 2 · Answer 2 · edited May 23 '17 at 11:50

2

Problem root:

Your problem is in this line

 Certificates testCertificates = 
             new Certificates(BitmapFactory.decodeFile(Context.STORAGE_SERVICE));

The parameter to decodeFile is invalid hence it returns null. The parameter should be the path to the image file, whereas you are passing a constant that is to be used for retrieving the storage service.

Fix:

You already have the bitmap in SaveData activity. You need to pass it to CheckData activity through intent. Add the bitmap to the intent :

   case R.id.Button01check:
        Intent intent = new Intent(this, CheckData.class);
        intent.putExtra("BitmapImage", bitmap);
        startActivity(intent);

Then in CheckData activity, retrieve the bitmap from intent and create the Certificates object.

Bitmap bitmap = (Bitmap) getIntent().getParcelableExtra("BitmapImage");
Certificates testCertificates = new Certificates(bitmap );

Reference: How can I pass a Bitmap object from one activity to another

edited May 23 '17 at 11:50

Community

1
1

answered Jun 28 '12 at 05:38

Ron

24,175
8
56
97

bitmap and intent cannot be resolved.. How can i resolve them – Abhinai Jun 28 '12 at 08:04
imported package for Bitmap but getting error on bitmap and intent if i import intent then i am getting an error as Cannot make a static reference to the non-static method getParcelableExtra(String) from the type Intent – Abhinai Jun 28 '12 at 10:00
i am having the same error as nullpointer exception it didnt solve the problem for me – Abhinai Jun 28 '12 at 10:39
sorry to say but it didnt solve the problem for me, the same logcat and the same errors which are posted above at line 29 in checkData.java and 60 in DataMAnipulator.java – Abhinai Jun 28 '12 at 10:47
can i have your email id so that i can send this app to your emailid so that u can rectify the error – Abhinai Jun 28 '12 at 10:55

score 1 · Answer 3 · answered Jun 18 '12 at 10:30

1

Either certificates is null, or certificates.getBitmap() is returning null. Add logging to find out which.

answered Jun 18 '12 at 10:30

Graham Borland

60,055
21
138
179

its showing the same error when i checked whether the certificate is null or certificate entry is null – samsun Jun 18 '12 at 11:54

score 0 · Answer 4 · answered Jun 18 '12 at 10:33

0

check certificates is null or not before inserting data as:

public void createCertificatesEntry(Certificates certificates) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
  if(certificates !=null)
{
        certificates.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out);
        ContentValues cv = new ContentValues();
        cv.put(KEY_IMG, out.toByteArray());
        mDb.insert(CERTIFICATES_TABLE,  null, cv);
}
else
{
}

    }

answered Jun 18 '12 at 10:33

ρяσѕρєя K

132,198
53
198
213

sam u can also put validation for null on this line`DataManipulator.createCertificatesEntry( (Certificates) testCertificates);` – ρяσѕρєя K Jun 18 '12 at 10:40
its showing the same error when i checked whether the certificates entry is null – samsun Jun 18 '12 at 11:50

score -1 · Answer 5 · answered Jul 02 '12 at 21:50

generally , in order to handle exceptions, i would give you this tip:

when you get the exception on the logcat , double click (or press ENTER) each of the red lines of the logs in this chunk , till the text cursor goes to the correct line that you got the exception .

then , once you know on which of the variables you got the expcetion , put a breakpoint there ,on the event of clicking , and on the event of onCreate , to see why you got this exception .

however , your code has so many weird things , for example:

why do you call setContentView twice in the same method ?
why do you try to decode a bitmap file which its name is Context.STORAGE_SERVICE ?
why do you have a class and and instance with the same name (DataManipulator) ? please use a more standard way to name fields and variables.

nullpointer exception raises when i click on the button

5 Answers5

Problem root:

Fix:

Linked

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