Question

我正在编写一个代码来实现Android设备中的小图库。我的代码如下。代码正在运行，但是它会给出内存异常请帮忙。我很新鲜到android。提前谢谢。

public class GalleryActivity extends Activity{
/*
 * Storage Variable
 */
private int count;
private Bitmap[] thumbnails;        //Images to be displayed
private String[] arrPath;           //Path of the images to be displayed
private ImageAdapter imageAdapter;  //Set how the images to be displayed

Cursor imagecursor;                 //To move through the query
Layout grid;

/*
 * Shows the Images in the form of a gallery
 */
@SuppressWarnings("deprecation")
public void showGallery() {
    final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
    final String orderBy = MediaStore.Images.Media._ID;
    imagecursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                                columns,
                                null,
                                null, 
                                orderBy);
    int image_column_index = imagecursor.getColumnIndex(MediaStore.Images.Media._ID);
    this.count = imagecursor.getCount();
    this.thumbnails = new Bitmap[this.count];
    this.arrPath = new String[this.count];
    GridView imagegrid = (GridView) findViewById(R.id.PhotoGrid);
    imageAdapter = new ImageAdapter();
    imagegrid.setAdapter(imageAdapter);

    for (int i = 0; i < this.count; i++) {
        imagecursor.moveToPosition(i);
        int id = imagecursor.getInt(image_column_index);
        int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
        thumbnails[i] = MediaStore.Images.Thumbnails.getThumbnail(
                getApplicationContext().getContentResolver(), id,
                MediaStore.Images.Thumbnails.MICRO_KIND, null);
        arrPath[i]= imagecursor.getString(dataColumnIndex);

    }
}


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Intent intent = getIntent();            // To know from where the activity was called
    String action = intent.getAction();
    String type = intent.getType();
    showGallery();
}

@Override
public void onLowMemory() {
    System.gc();
    System.out.println("Low Memory $$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
    super.onLowMemory();
}

/*
 * Unregister every resource before exiting
 * @see android.app.Activity#onDestroy()
 */
@Override
protected void onDestroy() {
    super.onDestroy();
    if(imagecursor != null){
        imagecursor.close();
    }
    if(socket != null){
        try {
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/*
 * Class        : ImageAdapter
 * Description  : Contains functions to populate the GridView to form an image
 */
public class ImageAdapter extends BaseAdapter {
    private LayoutInflater mInflater;

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

    @Override
    public int getCount() {
        return count;
    }

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView holder;
        convertView = mInflater.inflate(
        R.layout.one_image, null);
        holder = (ImageView)convertView.findViewById(R.id.PhotoImage);
        convertView.setTag(holder);
        holder.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                int id = v.getId();
                System.out.println(String.valueOf(id));
                Intent intent = new Intent(GalleryActivity.this, ViewImage.class);
                intent.putExtra("path", arrPath[id]);
                intent.putExtra("command", "upload");
                System.out.println(arrPath[id]);
                startActivity(intent);
            }
        });
        holder.setImageBitmap(thumbnails[position]);
        holder.setId(position);
        return convertView;
    }
}// ImageAdapter

public class SimpleGestureDetector extends SimpleOnGestureListener implements OnClickListener{

    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_MAX_OFF_PATH = 250;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        return super.onDoubleTap(e);
    }

    @Override
    public void onClick(View arg0) {

    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        try {
            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            // right to left swipe
            if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {

            }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                System.out.println("Left");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }
}

}// GalleryActivity

Answer 1

This post将真正帮助您，还有一些Google I / O视频讨论此主题，请查看：2013 one

Answer 2

使用convertView不为null然后尝试其他

     @Override
            public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder2;
        if (convertView == null) {

                holder2 = new ViewHolder();
                convertView = mInflater.inflate(
                R.layout.one_image, null);
                holder1 = (ImageView)convertView.findViewById(R.id.PhotoImage);
                convertView.setTag(holder1);

              }
           else {

            holder2= (ViewHolder) convertView .getTag();
            }

                return convertView;
            }

private static class ViewHolder {
        ImageView holder1;

    }

Answer 3

最好使用已经可用于此目的的Universal Image Loader库。你无需担心任何事情，只需查看他们的文档即可。请参阅此处：https://github.com/nostra13/Android-Universal-Image-Loader

实现图库时的内存不足

3 个答案: