我有一个能够通过onLongClick删除特定图像的列表视图，但到目前为止它还没有工作。测试时，会出现对话框如果我想要删除，我按是/确定并且吐司显示项目已删除，但该项目仍在那里。
更新（由于user1140237，我的删除和删除功能正常工作）
更新主要活动
private String[] FilePathStrings;
private String[] FileNameStrings;
private File[] listFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yearbook);
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"/CapturyGallery");
// Check for SD Card
if (!Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "Error! No SDCARD Found!", Toast.LENGTH_LONG)
.show();
} else {
// Locate the image folder in your SD Card
file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"/CapturyGallery");
// Create a new folder if no folder named CapturyGallery exist
file.mkdirs();
}
if (file.isDirectory())
{
listFile = file.listFiles();
// Create a String array for FilePathStrings
FilePathStrings = new String[listFile.length];
// Create a String array for FileNameStrings
FileNameStrings = new String[listFile.length];
for (int i = 0; i < listFile.length; i++)
{
//Get the path image file
FilePathStrings[i] = listFile[i].getAbsolutePath();
// Get the name image file
FileNameStrings[i] = listFile[i].getName();
}
}
Arrays.sort(listFile);
final ListAdapter listAdapter = new CustomAdapter(Yearbook.this, FilePathStrings, FileNameStrings);
ListView lv = (ListView) findViewById(R.id.ListingView);
lv.setAdapter(listAdapter);
final ArrayList<String> list = new ArrayList(Arrays.asList(FilePathStrings));
lv.setOnItemClickListener(this);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
//Deletes item
AlertDialog.Builder adb=new AlertDialog.Builder(Yearbook.this);
adb.setTitle("Delete?");
adb.setMessage("Are you sure you want to delete " + FileNameStrings[position]);
final int positionToRemove = position;
adb.setNegativeButton("Cancel", null);
adb.setPositiveButton("Ok", new AlertDialog.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
File file = new File(list.get(positionToRemove));
if (file.delete()) {
list.remove(position);
((CustomAdapter) listAdapter).updateMyData(FilePathStrings, FileNameStrings);
Toast.makeText(getApplicationContext(), FileNameStrings[position] + " deleted", Toast.LENGTH_LONG).show();
}
}
});
adb.show();
return true;
}
});
}
CUSTOMADAPTER
public class CustomAdapter extends BaseAdapter {
private Activity activity;
private String[] filepath;
private String[] filename;
private static LayoutInflater inflater = null;
public CustomAdapter(Activity a, String[] fpath, String[] fname) {
activity = a;
filepath = fpath;
filename = fname;
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void updateMyData(String[] fpath, String[] fname) {
filepath = fpath;
filename = fname;
notifyDataSetChanged();
}
@Override
public int getCount() {
return filepath.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
class MyViewHolder {
ImageView myImage;
TextView timestamp;
TextView myName;
TextView myHeader;
MyViewHolder(View v) {
myImage = (ImageView) v.findViewById(R.id.PicView);
timestamp = (TextView) v.findViewById(R.id.timestamp);
myName = (TextView) v.findViewById(R.id.myName);
myHeader = (TextView) v.findViewById(R.id.textSeparator);
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
MyViewHolder holder = null;
if (vi == null) {
vi = inflater.inflate(R.layout.custom_row, null);
holder = new MyViewHolder(vi);
vi.setTag(holder);
} else {
holder = (MyViewHolder) vi.getTag();
}
Bitmap bmp = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(filepath[position]),100,100);
holder.myImage.setImageBitmap(bmp);
//PicImage.setScaleType(ImageView.ScaleType.CENTER_CROP);
holder.myImage.setPadding(8, 8, 8, 8);
//Set Title
holder.myName.setText(filename[position]);
ExifInterface intf = null;
try {
intf = new ExifInterface(filepath[position]);
} catch(IOException e) {
e.printStackTrace();
}
if(intf != null) {
String dateString = intf.getAttribute(ExifInterface.TAG_DATETIME);
holder.timestamp.setText("Date Taken: " + dateString.toString());
}
return vi;
}
所以我的最后一个问题是，每当我从列表视图中删除某些内容时，它就会崩溃。但是，该文件确实被删除了。我不确定是什么错误，因为我在手机上测试了它
答案 0 :(得分：1)
您还需要更新自定义适配器中的列表数据。删除后比调用notifydatasetchanged
在您的惯例中保留以下方法来更新列表数据＆amp;之后在longpress中调用它
public void updateMyData(String[] fpath, String[] fname) {
filepath = fpath;
filename = fname;
notifyDataSetChanged();
}
您需要从longPress
调用此方法 list.remove(position);
((CustomAdapter )listAdapter).updateMyData( FilePathStrings, FileNameStrings); /// here in your case you need to define both array global sorry not time to clean up your code
Toast.makeText(getApplicationContext(), FileNameStrings[position] +" deleted",Toast.LENGTH_LONG).show();
<强>已更新
从提到的目录中删除文件＆amp;更新列表视图您需要先从该位置删除文件，而不是需要更新listview
File file = new File(list.get(position));
if (file.delete()) {// this will required permission in Manifest for Write_EXTERNAL_STORATE
// if file is deleted from SD CARD
list.remove(position);
((CustomAdapter )listAdapter).updateMyData( FilePathStrings, FileNameStrings); /// here in your case you need to define both array global sorry not time to clean up your code
Toast.makeText(getApplicationContext(), FileNameStrings[position] + " deleted", Toast.LENGTH_LONG).show();
}
* CustomAdapter *
public class CustomAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<String> filepath;
private ArrayList<String> filename;
private JSONArray jListData;
private int size = 0;
public CustomAdapter(Activity a, JSONArray jListData) {
activity = a;
this.jListData = jListData;
if (filepath != null)
size = jListData.length();
}
public void updateMyData(JSONArray jListData) {
this.jListData = jListData;
size = jListData.length();
notifyDataSetChanged();
}
@Override
public int getCount() {
return size;
}
public JSONObject getItem(int position) {
try {
return (JSONObject) jListData.get(position);
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
public long getItemId(int position) {
return position;
}
class MyViewHolder {
ImageView myImage;
TextView timestamp;
TextView myName;
TextView myHeader;
MyViewHolder(View v) {
myImage = (ImageView) v.findViewById(R.id.PicView);
timestamp = (TextView) v.findViewById(R.id.timestamp);
myName = (TextView) v.findViewById(R.id.myName);
myHeader = (TextView) v.findViewById(R.id.textSeparator);
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
MyViewHolder holder = null;
try {
if (vi == null) {
vi = LayoutInflater.from(activity).inflate(R.layout.custom_row, parent, false);
holder = new MyViewHolder(vi);
vi.setTag(holder);
} else {
holder = (MyViewHolder) vi.getTag();
}
JSONObject rowObject = this.jListData.getJSONObject(position);
Bitmap bmp = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(rowObject.optString("filename")), 100, 100);
holder.myImage.setImageBitmap(bmp);
//PicImage.setScaleType(ImageView.ScaleType.CENTER_CROP);
holder.myImage.setPadding(8, 8, 8, 8);
//Set Title
holder.myName.setText(rowObject.optString("filename"));
ExifInterface intf = null;
try {
intf = new ExifInterface(rowObject.optString("filepath"));
} catch (IOException e) {
e.printStackTrace();
}
if (intf != null) {
String dateString = intf.getAttribute(ExifInterface.TAG_DATETIME);
holder.timestamp.setText("Date Taken: " + dateString.toString());
}
} catch (JSONException e) {
}
return vi;
}
}
<强> 活性
private JSONArray jArrayFileData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yearbook);
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "/CapturyGallery");
// Check for SD Card
if (!Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "Error! No SDCARD Found!", Toast.LENGTH_LONG)
.show();
} else {
// Locate the image folder in your SD Card
file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "/CapturyGallery");
// Create a new folder if no folder named CapturyGallery exist
file.mkdirs();
}
jArrayFileData = new JSONArray();
if (file.isDirectory()) {
listFile = file.listFiles();
// Create a String array for FilePathStrings
FilePathStrings = new String[listFile.length];
// Create a String array for FileNameStrings
FileNameStrings = new String[listFile.length];
for (int i = 0; i < listFile.length; i++) {
JSONObject jObject = new JSONObject();
//Get the path image file
// FilePathStrings[i] = listFile[i].getAbsolutePath();
// Get the name image file
// FileNameStrings[i] = listFile[i].getName();
jObject.put("filepath", listFile[i].getAbsolutePath());
jObject.put("filename", listFile[i].getName());
jArrayFileData.put(jObject);
}
}
// Arrays.sort(listFile);
final ListAdapter listAdapter = new CustomAdapter(Yearbook.this, jArrayFileData);
ListView lv = (ListView) findViewById(R.id.ListingView);
lv.setAdapter(listAdapter);
// final ArrayList<String> list = new ArrayList(Arrays.asList(FilePathStrings));
lv.setOnItemClickListener(this);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
//Deletes item
AlertDialog.Builder adb = new AlertDialog.Builder(Yearbook.this);
adb.setTitle("Delete?");
adb.setMessage("Are you sure you want to delete " + FileNameStrings[position]);
final int positionToRemove = position;
adb.setNegativeButton("Cancel", null);
adb.setPositiveButton("Ok", new AlertDialog.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
try {
File file = new File(list.get(positionToRemove));
if (file.delete()) {
Toast.makeText(getApplicationContext(), jArrayFileData.getJSONObject(position).optString("filename") + " deleted", Toast.LENGTH_LONG).show();
jArrayFileData.remove(position);
// list.remove(position);
((CustomAdapter) listAdapter).updateMyData(jArrayFileData);
}
} catch (JSONException e) {
}
}
});
adb.show();
return true;
}
});
}
答案 1 :(得分：0)
在代码中使用Arraylist<String>表示fpath和fname：然后从列表视图中删除数据。
使用此：
fpath.remove(index_toDelete);
fpath.remove(index_toDelete);
customAdapter.notifyDataSetChanged();