尝试在列表视图的一侧显示缩略图

Question

我目前有一个listview，在选择目录后按字母顺序显示目录中的所有 .cue 文件，它使用 和外部程序来处理 .cue 文件。 我想做的是在后台的imageview中显示与 cue 文件匹配的缩略图。 例如，如果我在同一目录中有一个名为"a.cue"和"a.png"的文件， 当"a.cue"在listview中突出显示时， "a.png"同时在背景中显示为缩略图。这是我当前的代码：

public class openfileactivity7 extends Activity {
File path;
ListView list;
static ArrayList<String> bin_paths=new ArrayList<String>();
static ArrayList<String> bin_names=new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (audioplay.isplayingAudio) {

} else {audioplay.playAudio(this, R.raw.boot);
}

list=(ListView)findViewById(R.id.listView1);

bin_paths.clear();
bin_names.clear();

path = new File("/mnt/usb_storage/USB_DISK0/udisk0/cue/pcecd");
searchFolderRecursive1(path);


ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, bin_names);

Collections.sort(bin_paths);
Collections.sort(bin_names);
adapter.sort(new Comparator<String>() {
@Override
public int compare(String lhs, String rhs) {
return lhs.compareTo(rhs);
}
});

list.setAdapter(adapter);

list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
String path = bin_paths.get(arg2);
File file = new File(path);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file), "application/cue");
intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
startActivity(intent);
if (audioplay.isplayingAudio) {
audioplay.stopAudio();
}
startActivity(intent);
}
});
}


private static void searchFolderRecursive1(File folder)
{
if (folder != null)
{
if (folder.listFiles() != null)
{
for (File file : folder.listFiles())
{
if (file.isFile())
{
if(file.getName().contains(".cue"))
{
//   Log.e("ooooooooooooo", "path__="+file.getName());
file.getPath();
bin_names.add(file.getName());
bin_paths.add(file.getPath());
//    Log.e("bin_paths", ""+bin_names);
}
}
else
{
searchFolderRecursive1(file);
}
}
}
}
}

}

Answer 1

尝试以下示例(未测试下面的代码(。

1(主要活动.class-------------------

public class MainActivity extends AppCompatActivity implements ItemAdapter.Listener {
private ListView lv;
private ItemAdapter itemAdapter;
private List<String> bin_names;
private List<String> bin_paths;
private List<String> bin_images_paths;
private static final String NO_IMAGE = "no_image";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.demo11);
//Search for .cue files --- populate bin_names --- populate bin_path ---
// check if an image (in the same directory) for the corresponding .cue file exists:
// if yes add image path otherwise add NO_IMAGE.
// done with data population part...
lv = (ListView) findViewById(R.id.lv);
itemAdapter = new ItemAdapter(getApplication() , bin_names , bin_paths , bin_images_paths , MainActivity.this);
lv.setAdapter(itemAdapter);
}
@Override
protected void onResume() {
super.onResume();
if(itemAdapter != null){// refresh data
itemAdapter.notifyDataSetChanged();
}
}
@Override
public void PlayM(int position) {
//open file
// get file path by using bin_paths.get(position).
File file = new File(bin_paths.get(position));
if(file.exists()){
if(file.getName().contains(".cue")){
Toast.makeText(getApplicationContext() , "Play " + bin_paths.get(position) , Toast.LENGTH_LONG).show();
}else{
//refresh data.
if(itemAdapter != null){
itemAdapter.notifyDataSetChanged();
}
}
}else{
//refresh data.
if(itemAdapter != null){
itemAdapter.notifyDataSetChanged();
}
}
}
}

2( 项目适配器.class---------------------------

public class ItemAdapter extends BaseAdapter {
private Context mContext;
private LayoutInflater layoutInflater;
private Listener callback;
private List<String> n = new ArrayList<String>();
private List<String> p = new ArrayList<String>();
private List<String> i = new ArrayList<String>();

public ItemAdapter(Context c , List<String> n , List<String> p , List<String> i , Listener l) {
mContext = c;
callback = l;
this.n = n; //names
this.p = p; //paths
this.i = i; //images;
layoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
return p.size();
}
public Object getItem(int position) {
return p.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(final int position, View convertView, ViewGroup parent) {
TextView tv;
ImageView iv;
View view = convertView;

if (convertView == null) {
if (layoutInflater != null) {
view = layoutInflater.inflate(R.layout.demo10, null);
}
}
tv = (TextView) view.findViewById(R.id.tv);
iv = (ImageView) view.findViewById(R.id.iv);
File file = new File(p.get(position));
if(file.exists()){
if(!file.getName().contains(".cue")){// is not a .cue file
n.remove(position);
p.remove(position);
i.remove(position);
this.notifyDataSetChanged();
}else{
//everything is fine.
tv.setText(n.get(position));
tv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(callback != null) {
callback.PlayM(position);
}
}
});
File image = new File(i.get(position)); // check if image exists
if(image.exists()){
if(image.getName().contains(".jpg") || image.getName().contains(".png")){
Bitmap b = BitmapFactory.decodeFile(i.get(position));
iv.setImageBitmap(b);
iv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(callback != null){
callback.PlayM(position);
}
}
});
}else{
// hide imageView
iv.setVisibility(View.GONE);
}
}else{
// hide imageView
iv.setVisibility(View.GONE);
}
}
}else{ // doesn't exist
n.remove(position);
p.remove(position);
i.remove(position);
this.notifyDataSetChanged();
}
return view;
}
public interface Listener {
public void PlayM(int position);
}
}

3( 演示11.xml--------------

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/lv">
</ListView>
</android.support.constraint.ConstraintLayout>

4( 演示10.xml-------------------

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tv"
android:textSize="17sp"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:layout_toStartOf="@id/iv"
android:layout_marginStart="20dp"
android:textStyle="bold"
android:text="Name"/>
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_weight="20"
android:layout_centerVertical="true"
android:layout_alignParentEnd="true"
android:layout_marginEnd="10dp"
android:id="@+id/iv"/>
</RelativeLayout>