Question

我的上传活动从图库中选择图片并上传。

我从另一个打开我的上传活动，当我在Marshmallow打开它时效果很好，但是当我从Lollipop打开它时，它需要花费太多时间才能打开。

我的代码有什么问题导致这种冲突？

    public class UploadActivity extends Activity {
    // LogCat tag
    private static final String TAG = ImagesForAds.class.getSimpleName();

    private int count;
    private Bitmap[] thumbnails;
    private boolean[] thumbnailsselection;
    private String[] arrPath;
    private ImageAdapter imageAdapter;
    private static final int PICK_FROM_CAMERA = 1;
    ArrayList<String> IPath = new ArrayList<String>();
    public static Uri uri;
    final String[] columns = { MediaStore.Images.Media.DATA,
            MediaStore.Images.Media._ID };
    final String orderBy = MediaStore.Images.Media._ID;
    Cursor imagecursor = managedQuery(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null,
            null, orderBy);
    int image_column_index = imagecursor
            .getColumnIndex(MediaStore.Images.Media._ID);

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

        this.count = imagecursor.getCount();
        this.thumbnails = new Bitmap[this.count];
        this.arrPath = new String[this.count];
        this.thumbnailsselection = new boolean[this.count];
        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);
        }
        GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);
        imageAdapter = new ImageAdapter();
        imagegrid.setAdapter(imageAdapter);
        imagecursor.close();
        final Button uploadBtn = (Button) findViewById(R.id.uploadDONE);
        uploadBtn.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                final int len = thumbnailsselection.length;
                int cnt = 0;
                String selectImages = "";
                for (int i = 0; i < len; i++) {
                    if (thumbnailsselection[i]) {
                        cnt++;
                        selectImages = arrPath[i];
                        IPath.add(selectImages);
                    }
                }

                if (cnt == 0) {
                    Toast.makeText(getApplicationContext(),
                            "Please select at least one image",
                            Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(getApplicationContext(),
                            "You've selected Total " + cnt + " image(s).",
                            Toast.LENGTH_LONG).show();
                    Log.d("SelectedImages", selectImages);

                    Intent intentMessage = new Intent(UploadActivity.this,
                            ImagesForAds.class);
                    intentMessage.putStringArrayListExtra("IMAGE", IPath);
                    startActivity(intentMessage);
                }
            }
        });
    }

    public class ImageAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

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

        public int getCount() {
            return count;
        }

        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);
                holder.checkbox = (CheckBox) convertView
                        .findViewById(R.id.itemCheckBox);

                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }
            holder.checkbox.setId(position);
            holder.imageview.setId(position);
            holder.checkbox.setOnClickListener(new View.OnClickListener() {

                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    CheckBox cb = (CheckBox) v;
                    int id = cb.getId();
                    if (thumbnailsselection[id]) {
                        cb.setChecked(false);
                        thumbnailsselection[id] = false;
                    } else {
                        cb.setChecked(true);
                        thumbnailsselection[id] = true;
                    }
                }
            });
            holder.imageview.setImageBitmap(thumbnails[position]);
            holder.checkbox.setChecked(thumbnailsselection[position]);
            holder.id = position;
            return convertView;
        }
    }

    class ViewHolder {
        ImageView imageview;
        CheckBox checkbox;
        int id;
    }

    @Override
    public void onBackPressed() {
        Intent i = new Intent(UploadActivity.this, ImagesForAds.class);
        UploadActivity.this.finish();
        startActivity(i);
        super.onBackPressed();
    }
}

Answer 1

你正在使用的棉花糖手机可能在媒体商店中有更多的图像，这就是你的活动开始缓慢的原因。

也就是说，您的代码中存在一般性能问题：

对游标中的每一行使用方法moveToPosition，最好在循环中使用moveToFirst和moveToNext方法。
您正在活动开始时将所有缩略图加载到内存中。当图像很多时，这可能需要很长时间，也可能很容易耗尽内存。最好根据需要在适配器中加载这些tumbnails。

更好的是，让你的适配器继承自CursorAdapter，这应该给你最好的启动时间。

我的UploadActivity和Lollipop版本之间存在冲突

1 个答案: