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端的信息。我还将位图位置存储到数据库中，当查看客户端信息时，该数据库在GridView中加载时是缩略图大小。
要选择图像，另一个Activity将从可以滚动的位置开始，并选择他们想要的图像，最多6张图像。
但是，在滚动整页并选择6张图片传递给客户Activity后，我会遇到Out Of Memory Exception。如何在开始下一个Activity之前清除内存？
这是我的Activity，他们最多可以选择6张图片
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！
为了澄清，我可以在没有OOM异常的情况下选择6张图片，但是只要我滚动浏览第一页或更多页面，我就会遇到OOM异常。
答案 0 :(得分：1)
您需要使用Glide来加载GridView中的图片，而不是AsyncTask函数中使用的setBitmap。
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;
}