Unable to view images properly in a GridView

问题

MainActivity:

public class AndroidCustomGalleryActivity extends Activity {
    private int count;
    private Bitmap[] thumbnails;
    private boolean[] thumbnailsselection;
    private String[] arrPath;
    private ImageAdapter imageAdapter;
    ArrayList<String> f = new ArrayList<String>();// list of file paths
    File[] listFile;
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_android_custom_gallery);
        getFromSdcard();
        GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);
        imageAdapter = new ImageAdapter();
        imagegrid.setAdapter(imageAdapter);


    }
    public void getFromSdcard()
    {
        File file= new File(android.os.Environment.getExternalStorageDirectory(),"SnapBoard");

            if (file.isDirectory())
            {
                listFile = file.listFiles();


                for (int i = 0; i < listFile.length; i++)
                {

                    f.add(listFile[i].getAbsolutePath());

                }
            }
    }

    public class ImageAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

        public ImageAdapter() {
            mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        public int getCount() {
            return f.size();
        }

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

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

        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder;
            if (convertView == null) {
                holder = new ViewHolder();
                convertView = mInflater.inflate(
                        R.layout.galleryitem, null);
                holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage);

                convertView.setTag(holder);
            }
            else {
                holder = (ViewHolder) convertView.getTag();
            }


            Bitmap myBitmap = BitmapFactory.decodeFile(f.get(position));
            holder.imageview.setImageBitmap(myBitmap);
            return convertView;
        }
    }
    class ViewHolder {
        ImageView imageview;


    }
        }

XML:

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


<GridView
    android:id="@+id/PhoneImageGrid"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:columnWidth="90dp"
    android:gravity="center"
    android:horizontalSpacing="10dp"
    android:numColumns="auto_fit"
    android:stretchMode="columnWidth"
    android:verticalSpacing="10dp" />


</RelativeLayout>

GalleryItem.xml :

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

    <ImageView
        android:id="@+id/thumbImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />

    <CheckBox
        android:id="@+id/itemCheckBox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true" />

</RelativeLayout>

SnapShot:

I am able to retrieve the images from a seperate folder from my SD card and display it in a grid view but the view seems rather collapsed. Does it has something to do with screen size ? I am using a Galaxy ACE DUOS (3.5 inch). Will try to post the screen shot shortly. Help will be much appreciated. Thanks in advance.

EDIT:

Logcat:

12-19 11:08:25.335: D/dalvikvm(22171): GC_EXTERNAL_ALLOC freed 66K, 47% free 2957K/5511K, external 58486K/58486K, paused 39ms
12-19 11:08:25.351: E/dalvikvm-heap(22171): 9830400-byte external allocation too large for this process.
12-19 11:08:25.390: E/GraphicsJNI(22171): VM won't let us allocate 9830400 bytes
12-19 11:08:25.390: D/dalvikvm(22171): GC_FOR_MALLOC freed <1K, 47% free 2957K/5511K, external 58486K/58486K, paused 30ms
12-19 11:08:25.390: D/skia(22171): --- decoder->decode returned false

回答1:

Instead of using a seperate imageview in your inflator what you have to do is remove imageview from inflator and set your thnumbnail as a background for your inflator relativewlayout.

回答2:

I think so your problem is when ur are getting the view of grid view there is mistake.

Error

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

Correction

public Object getItem(int position) {
        return f.get(position);
}

The error is because whenever you display image, you allocate the image size in Virtual memory. This can be overridden by resizing the bitmap and reducing the size and then display the image.

public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);

// "RECREATE" THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
return resizedBitmap;
}

In your Code

Bitmap myresizedbitmap= getResizedBitmap(myBitmap,300, 300);
holder.imageview.setImageBitmap(myresizedbitmap);

来源：https://stackoverflow.com/questions/20673919/unable-to-view-images-properly-in-a-gridview