How to save a bitmap on internal storage

this is my code I and I want to save this bitmap on my internal storage. The public boolean saveImageToInternalStorage is a code from google but I don't know how to use it. when I touch button2 follow the button1 action.

public class MainActivity extends Activity implements OnClickListener {
Button btn, btn1;
SurfaceView sv;
Bitmap bitmap;
Canvas canvas;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    btn=(Button)findViewById(R.id.button1);
    btn1=(Button)findViewById(R.id.button2);
    sv=(SurfaceView)findViewById(R.id.surfaceView1);

    btn.setOnClickListener(this);
    btn1.setOnClickListener(this);

    bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

}
@Override
public void onClick(View v) {
    canvas=sv.getHolder().lockCanvas();
    if(canvas==null) return;
    canvas.drawBitmap(bitmap, 100, 100, null);
    sv.getHolder().unlockCanvasAndPost(canvas);


}

public boolean saveImageToInternalStorage(Bitmap image) {

    try {
    // Use the compress method on the Bitmap object to write image to
    // the OutputStream
    FileOutputStream fos = openFileOutput("desiredFilename.png", Context.MODE_PRIVATE);

    // Writing the bitmap to the output stream
    image.compress(Bitmap.CompressFormat.PNG, 100, fos);
    fos.close();

    return true;
    } catch (Exception e) {
    Log.e("saveToInternalStorage()", e.getMessage());
    return false;
    }
    }
 }

Solution

To Save your bitmap in sdcard use the following code

Store Image

private void storeImage(Bitmap image) {
    File pictureFile = getOutputMediaFile();
    if (pictureFile == null) {
        Log.d(TAG,
                "Error creating media file, check storage permissions: ");// e.getMessage());
        return;
    } 
    try {
        FileOutputStream fos = new FileOutputStream(pictureFile);
        image.compress(Bitmap.CompressFormat.PNG, 90, fos);
        fos.close();
    } catch (FileNotFoundException e) {
        Log.d(TAG, "File not found: " + e.getMessage());
    } catch (IOException e) {
        Log.d(TAG, "Error accessing file: " + e.getMessage());
    }  
}

To Get the Path for Image Storage

/** Create a File for saving an image or video */
private  File getOutputMediaFile(){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this. 
    File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
            + "/Android/data/"
            + getApplicationContext().getPackageName()
            + "/Files"); 

    // 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()){
            return null;
        }
    } 
    // Create a media file name
    String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmm").format(new Date());
    File mediaFile;
        String mImageName="MI_"+ timeStamp +".jpg";
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);  
    return mediaFile;
}

EDIT From Your comments i have edited the onclick view in this the button1 and button2 functions will be executed separately.

public onClick(View v){

switch(v.getId()){
case R.id.button1:
//Your button 1 function
break;
case R.id. button2:
//Your button 2 function
break;
} 
}