java - 从手机存储传递选定图像时内存不足

Question

我正在创建一个应用程序，您可以在其中存储有关手机中客户的信息。我还将位图位置存储到数据库中，加载后查看客户端信息时，该数据库的缩略图大小为 GridView 中的缩略图大小。

要选择图像，另一个 Activity 将启动，他们可以滚动并选择他们想要的图像，最多 6 个图像。

但是，在滚动整个页面并选择 6 个图像传递给客户端 Activity 后，我遇到了内存不足异常。如何在开始下一个 Activity 之前清除内存？

这是我的Activity，他们在其中最多选择 6 张图像

public class CustomGalleryActivity extends Activity {

    private GridView grdImages;
    private Button btnSelect;
    private GalleryImageAdapter imageAdapter;
    private String[] arrPath;
    private boolean[] thumbnailsselection;
    private int ids[];
    private int count;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.custom_gallery);
        grdImages= (GridView) findViewById(R.id.grdImages);
        btnSelect= (Button) findViewById(R.id.btnSelect);

        final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
        final String orderBy = MediaStore.Images.Media._ID;
        @SuppressWarnings("deprecation")
        Cursor 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.arrPath = new String[this.count];
        ids = new int[count];
        this.thumbnailsselection = new boolean[this.count];

        for (int i = 0; i < this.count; i++) {
            imagecursor.moveToPosition(i);
            ids[i] = imagecursor.getInt(image_column_index);
            int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
            arrPath[i] = imagecursor.getString(dataColumnIndex);
        }

        imageAdapter = new GalleryImageAdapter();
        grdImages.setAdapter((ListAdapter) imageAdapter);
        imagecursor.close();

        btnSelect.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                selectOnClick();
            }
        });
    }

    @Override
    public void onBackPressed() {
        setResult(Activity.RESULT_CANCELED);
        super.onBackPressed();
    }

    /**
     * This method used to set bitmap.
     * @param iv represented ImageView
     * @param id represented id
     */
    private void setBitmap(final ImageView iv, final int id) {
        new AsyncTask<Void, Void, Bitmap>() {
            @Override
            protected Bitmap doInBackground(Void... params) {
                return MediaStore.Images.Thumbnails.getThumbnail(getApplicationContext().getContentResolver(), id, MediaStore.Images.Thumbnails.MICRO_KIND, null);
            }

            @Override
            protected void onPostExecute(Bitmap result) {
                super.onPostExecute(result);
                iv.setImageBitmap(result);
            }
        }.execute();
    }

    public class GalleryImageAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

        public GalleryImageAdapter() {
            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) {
            final ViewHolder holder;

            if (convertView == null) {
                holder = new ViewHolder();
                convertView = mInflater.inflate(R.layout.custom_gallery_item, null);
                holder.imgThumb = (ImageView) convertView.findViewById(R.id.imgThumb);
                holder.chkImage = (CheckBox) convertView.findViewById(R.id.chkImage);

                convertView.setTag(holder);

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

            holder.chkImage.setId(position);
            holder.imgThumb.setId(position);
            holder.chkImage.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    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.imgThumb.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    int id = holder.chkImage.getId();
                    if (thumbnailsselection[id]) {
                        holder.chkImage.setChecked(false);
                        thumbnailsselection[id] = false;
                    } else {
                        holder.chkImage.setChecked(true);
                        thumbnailsselection[id] = true;
                    }
                }
            });


            try {
                setBitmap(holder.imgThumb, ids[position]);
            } catch (Throwable e) {
            }
            holder.chkImage.setChecked(thumbnailsselection[position]);
            holder.id = position;
            return convertView;
        }
    }

    class ViewHolder {
        ImageView imgThumb;
        CheckBox chkImage;
        int id;
    }

    public void selectOnClick() {
        final int len = thumbnailsselection.length;
        int cnt = 0;
        int i;
        String selectImages = "";

        for (i = 0; i < len; i++) {
            if (thumbnailsselection[i]) {
                cnt++;
                selectImages = selectImages + arrPath[i] + "|";
            }
        }

        if (cnt < 6) {
            for(i = cnt; i < 6; i++) {
                selectImages = selectImages + "blank" + "|";
            }
        }

        if (cnt == 0 ) {
            selectImages = "blank|blank|blank|blank|blank|blank|";
        }

        if (cnt > 6) {
            Toast.makeText(getApplicationContext(), "Please only select 6 images.", Toast.LENGTH_LONG).show();

        } else {
            Log.d("SelectedImages", selectImages);
            Intent intent = new Intent();
            intent.putExtra("data", selectImages);
            setResult(Activity.RESULT_OK, intent);
            finish();
        }
    }
}

感谢您的任何意见或建议!

澄清一下，我可以选择 6 个图像，而不会出现 OOM 异常，但是当我滚动浏览第一页或更多页面时，我就会遇到 OOM 异常。

Answer 1

您需要使用Glide用于在 GridView 中加载图像，而不是在 setBitmap 函数中使用的 AsyncTask 中。

要在代码中添加 Glide，您需要在 build.gradle 文件中添加以下内容。

repositories {
  mavenCentral() // jcenter() works as well because it pulls from Maven Central
}

dependencies {
  compile 'com.github.bumptech.glide:glide:4.0.0-RC0'
  compile 'com.android.support:support-v4:25.3.1'
  annotationProcessor 'com.github.bumptech.glide:compiler:4.0.0-RC0'
}

然后您需要将 BitMap 转换为 ByteArray，然后像这样修改您的 setBitmap 函数。

private void setBitmap(final ImageView iv, final int id) {
    byte[] byteArray = 
        bitmapToByte(MediaStore.Images.Thumbnails.getThumbnail(getApplicationContext().getContentResolver(), id, MediaStore.Images.Thumbnails.MICRO_KIND, null);

    Glide.with(this).load(byteArray.asBitmap().into(iv);
}

private byte[] bitmapToByte(Bitmap bitmap){
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
    byte[] byteArray = stream.toByteArray();
    return byteArray;
}