图像缩略图设置不正确 [英] Image thumbnails not setting correctly
问题描述
我正在尝试制作文件浏览器.我实现了这一切,只是我的图像缩略图加载速度太慢.所以我读到我必须转移到 asynctask 然后在执行后更新 ui.在运行 asynctask 之前,我为所有文件提供了默认缩略图.在 asynctask 中,我将位置作为参数,因为我使用它们设置标签.然后我使用该位置检查文件.如果那是图像或视频,我会为它创建一个位图.在执行后,我创建了一个新的 viewholder 并使用 getTag(position) 为其分配相同的标签.然后我使用 setBitmapImage 分配位图.问题:即使对于不是图像/视频的文件,缩略图也会改变/闪烁.到目前为止我尝试过的事情:a)使用 AsyncTask 更新图像缩略图对于 Android ListView 不合适
b)Android ListView 使用 AsyncTask 更新图像缩略图原因 查看回收
I am trying to make a file explorer. I achieved it all except that my image thumbnails were loading too slow. So I read that I must move to asynctask and then in post execute update the ui. Before running asynctask I provide a default thumbnail to all my files. In asynctask I take position as parameter because I set tags using them. Then I check the file using that position. If thats image or video I create a bitmap for it. In post execute I create a new viewholder and assign it the same tag using getTag(position). Then I assign the bitmap using setBitmapImage. Problem: Thumbnails are changing/blinking even for the files that are not images/videos.
Things I have tried so far:
a)updating of Image Thumbnails using AsyncTask for Android ListView not coming proper
b)Android ListView updating of Image Thumbnails using AsyncTask Causes View recycling
这是我的 getView 代码:
here is my code for getView:
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
File file=new File(String.valueOf(filenames[position]));
if(file.isDirectory()){
img=R.drawable.folder;
}
else{
img=getImage(filenames[position]);
}
ViewHolder viewHolder = null;
if (convertView == null) {
LayoutInflater inflator = LayoutInflater.from(getContext());
convertView = inflator.inflate(R.layout.list_item, null);
viewHolder = new ViewHolder();
viewHolder.tv = (TextView) convertView.findViewById(R.id.textView1);
viewHolder.cb = (CheckBox) convertView.findViewById(R.id.checkBox1);
viewHolder.iv= (ImageView)convertView.findViewById(R.id.imageView);
viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int getPosition = (Integer) buttonView.getTag(); // Here we get the position that we have set for the checkbox using setTag.
myList.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state.
}
});
convertView.setTag(viewHolder);
convertView.setTag(R.id.textView1, viewHolder.tv);
convertView.setTag(R.id.checkBox1, viewHolder.cb);
convertView.setTag(R.id.checkBox1, viewHolder.iv);
}
else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.iv.getLayoutParams().height = 80;
viewHolder.iv.getLayoutParams().width = 80;
viewHolder.cb.setTag(position);
final ViewHolder ViewHolder= viewHolder;
ViewHolder.iv.setImageResource(img);
ViewHolder.tv.setText(myList.get(position).getName());
ViewHolder.cb.setChecked(myList.get(position).isSelected());
final View finalConvertView = convertView;
class myTask extends AsyncTask<Integer,Void,Bitmap>{
int pos;
public myTask(int pos){
this.pos=pos;
}
@Override
protected Bitmap doInBackground(Integer... params) {
Bitmap thumb=null;
if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){
thumb = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(String.valueOf(filenames[pos])), 64, 64);
}
else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){
thumb=ThumbnailUtils.createVideoThumbnail(filenames[pos].getPath(), MediaStore.Video.Thumbnails.MINI_KIND);
}
return thumb;
}
@Override
protected void onPostExecute(Bitmap thumb){
if(isCancelled()){
return;
}
ViewHolder v= (ViewHolder) finalConvertView.getTag(pos);
if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){
v.iv.setImageBitmap(thumb);
}
else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){
v.iv.setImageBitmap(thumb);
}
}
}
myTask m=new myTask(position);
m.execute();
return convertView;
}
推荐答案
我终于找到了答案.
这是 ListAdapter 类:
Here is the ListAdapter Class:
class ListAdapter extends ArrayAdapter<Modal> {
private final Context context;
private int img;
private List<Modal> myList;
private File filenames[];
private List<Integer> selectedItems=new ArrayList<Integer>();
private CheckBox cb;
public ListAdapter(Context context, List<Modal> list, File filenames[]) {
super(context, R.layout.list_item, list);
this.context = context;
this.myList = list;
this.filenames=filenames;
}
@Override
public int getViewTypeCount() {
if(getCount()>0){
return getCount();
}
return 1;
}
@Override
public int getItemViewType(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
static class ViewHolder {
TextView tv;
CheckBox cb;
static ImageView iv;
}
public int getImage(File filename){
if(String.valueOf(filename).contains(".rar")||String.valueOf(filename).contains(".zip")){
return R.drawable.archive;
}
else if(String.valueOf(filename).contains(".doc")||String.valueOf(filename).contains(".docx")){
return R.drawable.doc;
}
else if(String.valueOf(filename).contains(".pdf")){
return R.drawable.pdf;
}
else if(String.valueOf(filename).contains(".txt")){
return R.drawable.txt;
}
else if(String.valueOf(filename).contains(".ppt")||String.valueOf(filename).contains(".pptx")){
return R.drawable.ppt;
}
else if(String.valueOf(filename).contains(".xls")||String.valueOf(filename).contains(".xlsx")){
return R.drawable.xls;
}
else if((String.valueOf(filename).contains(".jpeg")||String.valueOf(filename).contains(".jpg")||String.valueOf(filename).contains(".png")||String.valueOf(filename).contains(".bmp")||String.valueOf(filename).contains(".webp")||String.valueOf(filename).contains(".gif"))){
return R.drawable.image;
}
else if((String.valueOf(filename).contains(".mp4")||String.valueOf(filename).contains(".mkv")||String.valueOf(filename).contains(".webm")||String.valueOf(filename).contains(".3gp")||String.valueOf(filename).contains(".3gpp"))||String.valueOf(filename).contains(".MOV")){
return R.drawable.video;
}
else if((String.valueOf(filename).contains(".mp3")||String.valueOf(filename).contains(".wav")||String.valueOf(filename).contains(".wma")||String.valueOf(filename).contains(".MP2")||String.valueOf(filename).contains(".AAC")||String.valueOf(filename).contains(".AC3")||String.valueOf(filename).contains(".AU")||String.valueOf(filename).contains(".OGG")||String.valueOf(filename).contains(".FLAC"))){
return R.drawable.music;
}
else {
return R.drawable.unknown;
}
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
File file=new File(String.valueOf(filenames[position]));
if(file.isDirectory()){
img=R.drawable.folder;
}
else{
img=getImage(filenames[position]);
}
ViewHolder viewHolder = null;
if (convertView == null) {
LayoutInflater inflator = LayoutInflater.from(getContext());
convertView = inflator.inflate(R.layout.list_item, null);
viewHolder = new ViewHolder();
viewHolder.tv = (TextView) convertView.findViewById(R.id.textView1);
viewHolder.cb = (CheckBox) convertView.findViewById(R.id.checkBox1);
viewHolder.iv= (ImageView)convertView.findViewById(imageView);
viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int getPosition = (Integer) buttonView.getTag(); // Here we get the position that we have set for the checkbox using setTag.
myList.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state.
}
});
convertView.setTag(viewHolder);
convertView.setTag(R.id.textView1, viewHolder.tv);
convertView.setTag(R.id.checkBox1, viewHolder.cb);
convertView.setTag(R.id.checkBox1, viewHolder.iv);
}
else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.iv.getLayoutParams().height = 150;
viewHolder.iv.getLayoutParams().width = 150;
viewHolder.cb.setTag(position);
final ViewHolder ViewHolder= viewHolder;
ViewHolder.tv.setText(myList.get(position).getName());
ViewHolder.cb.setChecked(myList.get(position).isSelected());
viewHolder.iv.setImageResource(img);
Log.v("this","viewHolderMT: "+String.valueOf(viewHolder)+" position: "+position);
myTask m=new myTask(position,viewHolder.iv);
m.execute();
return convertView;
}
class myTask extends AsyncTask<Integer,Bitmap,Bitmap>{
int pos;
ImageView iv;
public myTask(int pos,ImageView iv){
this.pos=pos;
this.iv=iv;
iv.setTag(pos);
}
@Override
protected Bitmap doInBackground(Integer... params) {
Bitmap thumb=null;
if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){
thumb = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(String.valueOf(filenames[pos])), 150, 150);
}
else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")||String.valueOf(filenames[pos]).contains(".MOV")){
thumb=ThumbnailUtils.createVideoThumbnail(filenames[pos].getPath(), MediaStore.Video.Thumbnails.MINI_KIND);
}
return thumb;
}
@Override
protected void onProgressUpdate(Bitmap... thumb){
}
@Override
protected void onPostExecute(Bitmap thumb){
if(thumb!=null && (Integer)iv.getTag()==this.pos) {
if ((String.valueOf(filenames[pos])).contains(".jpeg") || String.valueOf(filenames[pos]).contains(".jpg") || String.valueOf(filenames[pos]).contains(".png") || String.valueOf(filenames[pos]).contains(".bmp") || String.valueOf(filenames[pos]).contains(".webp") || String.valueOf(filenames[pos]).contains(".gif")) {
iv.setImageBitmap(thumb);
}
else if ((String.valueOf(filenames[pos])).contains(".mp4") ||String.valueOf(filenames[pos]).contains(".MOV")|| String.valueOf(filenames[pos]).contains(".mkv") || String.valueOf(filenames[pos]).contains(".webm") || String.valueOf(filenames[pos]).contains(".3gp") || String.valueOf(filenames[pos]).contains(".3gpp")) {
iv.setImageBitmap(thumb);
}
}
}
}
}
我犯的错误:
- 将 AsyncTask 移到 getview() 之外
- 在异步构造函数中引用 imageView
- 同时实现 getItemViewType() 和 getItemId() 函数
- 没有检查 onPostExecute 中的位置标签,因此图像乱码.
我花了一段时间才弄明白.希望能帮到其他人!
This took a while for me to figure out. Hope it helps others!
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