Can not pass bitmap between activities in android

问题

I need to change background of the activity dynamically , by selecting an image from an other activity. and passing the selected image back to the calling activity , but when i try to get the image , it is null. here is my code.

  public class SelectGoalBackground extends OrmLiteBaseActivity<DatabaseHelper> {// implements{



GridView gridview ;
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.select_goal_background);
   final String from = getIntent().getExtras().getString("from");
    goalsList = new ArrayList<Goal>();

    try {
        goalsList = getTop3Goals();
    } catch (SQLException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (java.sql.SQLException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }


     gridview = (GridView) findViewById(R.id.gridview);
    gridview.setAdapter(new ImageAdapter(this));

    gridview.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View v, int position, long id) {

           ImageView l = (ImageView)gridview.getChildAt(position);
              Drawable path= l.getDrawable();


            Bitmap bitmap = ((BitmapDrawable)path).getBitmap();

            Intent intent = new Intent(SelectGoalBackground.this, AlarmAppActivity.class);

            intent.putExtra("Bitmap", bitmap);
            startActivity(intent);
            SelectGoalBackground.this.finish();
            return;

    });

}


public class ImageAdapter extends BaseAdapter {
    private Context mContext;

    public ImageAdapter(Context c) {
        mContext = c;
    }

    public int getCount() {
        return mThumbIds.length;
    }

    public Object getItem(int position) {
        return null;
    }

    public long getItemId(int position) {
        return 0;
    }

    // create a new ImageView for each item referenced by the Adapter
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView imageView;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);
        } else {
            imageView = (ImageView) convertView;
        }
       Bitmap bm = BitmapFactory.decodeResource(getResources(), mThumbIds[position]);
        imageView.setImageBitmap(bm);
        return imageView;
    }

    // references to our images
    private Integer[] mThumbIds = {
            R.drawable.sample_0, R.drawable.sample_1

    };
}

and in calling activity i get this bitmap like this

    RelativeLayout rel_lay = (RelativeLayout) findViewById(R.id.main_lay);
    Bitmap bitmap = (Bitmap)this.getIntent().getParcelableExtra("Bitmap");


    if (bitmap != null) {

        Log.v("bitmap", "not null");
        Drawable drawable = new BitmapDrawable(getResources(), bitmap);
        rel_lay.setBackgroundDrawable(drawable);
    }

but bitmap is null here and it is not setting background of this activity. any kind of help is appreciated , plz help

回答1:

There are 3 Solutions to solve this issue.

1) First Convert Image into Byte Array and then pass into Intent and in next activity get byte array from Bundle and Convert into Image(Bitmap) and set into ImageView.

Convert Bitmap to Byte Array:-

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();

Pass byte array into intent:-

Intent intent = new Intent(this, NextActivity.class);
intent.putExtra("picture", byteArray);
startActivity(intent);

Get Byte Array from Bundle and Convert into Bitmap Image:-

Bundle extras = getIntent().getExtras();
byte[] byteArray = extras.getByteArray("picture");

Bitmap bmp = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);
ImageView image = (ImageView) findViewById(R.id.imageView1);

image.setImageBitmap(bmp);

2) First Save image into SDCard and in next activity set this image into ImageView.

3) Pass Bitmap into Intent and get bitmap in next activity from bundle, but the problem is if your Bitmap/Image size is big at that time the image is not load in next activity.

来源：https://stackoverflow.com/questions/11720589/can-not-pass-bitmap-between-activities-in-android

标签

android

bitmap

drawable