如何使用New Folder Picker API将图像从SD卡显示到ListView？(How to Display images from SD Card to ListView with the

如何使用New Folder Picker API将图像从SD卡显示到ListView？(How to Display images from SD Card to ListView with the New Folder Picker API?)

我正在尝试从SD卡中选择一个文件夹并显示该文件夹中的图像列表。

它在Android 5.0之前工作正常，所以我开始使用New SD Card Access API更新它以选择文件夹。

public void FolderSelectionAlertDialog_Lollipop() { Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE); startActivityForResult(intent, 556); } @Override public void onActivityResult(int requestCode, int resultCode, Intent resultData) { if(resultCode == RESULT_OK) { // Get Uri from Storage Access Framework. Uri_Lollipop = resultData.getData(); // Persist access permissions. this.getContentResolver().takePersistableUriPermission(Uri_Lollipop, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION); } }

由于某些原因，ListView中没有显示图像。

这是代码：

public void ListView_Load_Lollipop() { DocumentFile documentFile = DocumentFile.fromTreeUri(this, Uri_Lollipop); Locale defaultLocale = Locale.getDefault(); for(DocumentFile file : documentFile.listFiles()) { String FileName = file.getName(); if(FileName.toLowerCase(defaultLocale).endsWith(".jpg") || FileName.toLowerCase(defaultLocale).endsWith(".png") || FileName.toLowerCase(defaultLocale).endsWith(".jpeg")) { mListViewObject = new ListViewObject(); mListViewObject.setName(FileName); Uri uri = file.getUri(); String imagePath = uri.getPath(); mListViewObject.setImageUrl("file:///" + imagePath); ListViewObject_List.add(mListViewObject); } } }

适配器：

public View getView(final int position, View convertView, ViewGroup parent) { ViewHolder viewHolder = new ViewHolder(); LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (convertView == null) { convertView = inflater.inflate(R.layout.listview_layout, parent, false); viewHolder.imageView = (ImageView)convertView.findViewById(R.id.ListViewImage); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder)convertView.getTag(); } Picasso.with(mContext) .load(getItem(position).getImageUrl()) .fit() .centerCrop() .into(viewHolder.imageView); } class ViewHolder { RelativeLayout layout; ImageView imageView; }

有人可以指导我吗？

非常感谢

更新：4-28-16

我忘了添加这个

listViewAdapter = new ListViewAdapter(this, ListViewObject_List); listView.setAdapter(listViewAdapter);

至

public void ListView_Load_Lollipop() { DocumentFile documentFile = DocumentFile.fromTreeUri(this, Uri_Lollipop); Locale defaultLocale = Locale.getDefault(); for(DocumentFile file : documentFile.listFiles()) { String FileName = file.getName(); if(FileName.toLowerCase(defaultLocale).endsWith(".jpg") || FileName.toLowerCase(defaultLocale).endsWith(".png") || FileName.toLowerCase(defaultLocale).endsWith(".jpeg")) { mListViewObject = new ListViewObject(); mListViewObject.setName(FileName); Uri uri = file.getUri(); String imagePath = uri.getPath(); mListViewObject.setImageUrl("file:///" + imagePath); ListViewObject_List.add(mListViewObject); } } }

感谢@ CommonsWare的回答：我能够通过将图像Uri而不是图像路径直接传递给对象类来解决我的问题。

我希望将来可以帮助别人。

I am trying to select a folder from SD Card and display the list of images inside this folder.

It was working fine until Android 5.0, so I started updating it with the New SD Card Access API to pick the folder.

public void FolderSelectionAlertDialog_Lollipop() { Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE); startActivityForResult(intent, 556); } @Override public void onActivityResult(int requestCode, int resultCode, Intent resultData) { if(resultCode == RESULT_OK) { // Get Uri from Storage Access Framework. Uri_Lollipop = resultData.getData(); // Persist access permissions. this.getContentResolver().takePersistableUriPermission(Uri_Lollipop, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION); } }

For some reasons, there is no image showing in the ListView.

Here is the code:

public void ListView_Load_Lollipop() { DocumentFile documentFile = DocumentFile.fromTreeUri(this, Uri_Lollipop); Locale defaultLocale = Locale.getDefault(); for(DocumentFile file : documentFile.listFiles()) { String FileName = file.getName(); if(FileName.toLowerCase(defaultLocale).endsWith(".jpg") || FileName.toLowerCase(defaultLocale).endsWith(".png") || FileName.toLowerCase(defaultLocale).endsWith(".jpeg")) { mListViewObject = new ListViewObject(); mListViewObject.setName(FileName); Uri uri = file.getUri(); String imagePath = uri.getPath(); mListViewObject.setImageUrl("file:///" + imagePath); ListViewObject_List.add(mListViewObject); } } }

Adapter:

public View getView(final int position, View convertView, ViewGroup parent) { ViewHolder viewHolder = new ViewHolder(); LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (convertView == null) { convertView = inflater.inflate(R.layout.listview_layout, parent, false); viewHolder.imageView = (ImageView)convertView.findViewById(R.id.ListViewImage); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder)convertView.getTag(); } Picasso.with(mContext) .load(getItem(position).getImageUrl()) .fit() .centerCrop() .into(viewHolder.imageView); } class ViewHolder { RelativeLayout layout; ImageView imageView; }

Can someone please guide me on this?

Thanks a lot

Update: 4-28-16

I forgot to add this

listViewAdapter = new ListViewAdapter(this, ListViewObject_List); listView.setAdapter(listViewAdapter);

to

public void ListView_Load_Lollipop() { DocumentFile documentFile = DocumentFile.fromTreeUri(this, Uri_Lollipop); Locale defaultLocale = Locale.getDefault(); for(DocumentFile file : documentFile.listFiles()) { String FileName = file.getName(); if(FileName.toLowerCase(defaultLocale).endsWith(".jpg") || FileName.toLowerCase(defaultLocale).endsWith(".png") || FileName.toLowerCase(defaultLocale).endsWith(".jpeg")) { mListViewObject = new ListViewObject(); mListViewObject.setName(FileName); Uri uri = file.getUri(); String imagePath = uri.getPath(); mListViewObject.setImageUrl("file:///" + imagePath); ListViewObject_List.add(mListViewObject); } } }

Thanks to @CommonsWare's answer: I was able to resolve my problem by passing the image Uri instead of the image path directly to the object class.

I hope it helps someone else in the future.