其实我已经制作了一个自定义画廊。所有图像都显示在我的自定义图库中。但这是一个问题。使用删除按钮删除图像时，图像文件将从内存中删除，但仍会显示图像（我的意思是保留缩略图）。如何清除数据并立即刷新库。
这是我的代码如下
MainActivity.java
public class MainActivity extends Activity {
private int count;
private Bitmap[] thumbnails;
private boolean[] thumbnailsselection;
private String[] arrPath;
private ImageAdapter imageAdapter;
File file = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
show();
final Button selectBtn = (Button) findViewById(R.id.selectBtn);
final Button shareBtn = (Button) findViewById(R.id.btnShare);
//delete image.
selectBtn.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
final int len = thumbnailsselection.length;
int cnt = 0;
String selectImages = "";
for (int i =0; i<len; i++)
{
if (thumbnailsselection[i])
{
cnt++;
selectImages = selectImages + arrPath[i] +" | ";
file= new File(arrPath[i]);
if(file.exists())
{
file.delete();
Log.v("roni", selectImages);
//arrPath[i] = null;
//selectImages = null;
Log.v("roni", arrPath[i]);
}
}
}
if (cnt == 0){
Toast.makeText(getApplicationContext(),
"Please select at least one image",
Toast.LENGTH_LONG).show();
} else
{
//thumbnails= null;
show();
Toast.makeText(getApplicationContext(),cnt +" Images Deleted ",Toast.LENGTH_LONG).show();
Log.v("SelectedImages", selectImages);
}
}
});
//share image.
shareBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND_MULTIPLE);
final int len = thumbnailsselection.length;
int cnt = 0;
ArrayList<Uri> imageUris = new ArrayList<Uri>();
Uri path= null;
String selectImages = "";
for (int i =0; i<len; i++)
{
if (thumbnailsselection[i])
{
cnt++;
selectImages = selectImages + arrPath[i] +" | ";
Log.v("roni", selectImages);
path = Uri.parse(arrPath[i]);
imageUris.add(path);
}
}
if (cnt == 0){
Toast.makeText(getApplicationContext(),
"Please select at least one image",
Toast.LENGTH_LONG).show();
} else
{
Log.v("roni", selectImages);
Toast.makeText(getApplicationContext(),cnt +" Images shared ",Toast.LENGTH_SHORT).show();
Log.d("SelectedImages", selectImages);
}
shareIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, imageUris);
shareIntent.setType("image/*");
startActivity(Intent.createChooser(shareIntent, "Share images to.."));
startActivity(shareIntent);
}
});
show();
}
public void show() {
//stored data
final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
final String orderBy = MediaStore.Images.Media._ID;
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.thumbnails = new Bitmap[this.count];
this.arrPath = new String[this.count];
this.thumbnailsselection = new boolean[this.count];
//move image
for (int i = 0; i < this.count; i++) {
imagecursor.moveToPosition(i);
int id = imagecursor.getInt(image_column_index);
int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
thumbnails[i] = MediaStore.Images.Thumbnails.getThumbnail(getApplicationContext().getContentResolver(), id,
MediaStore.Images.Thumbnails.MINI_KIND, null);
arrPath[i]= imagecursor.getString(dataColumnIndex);
}
GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);
imageAdapter = new ImageAdapter();
imagegrid.setAdapter(imageAdapter);
imagecursor.close();
}
public class ImageAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public ImageAdapter() {
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) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.galleryitem, null);
holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.itemCheckBox);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
holder.checkbox.setId(position);
holder.imageview.setId(position);
holder.checkbox.setOnClickListener(new 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.imageview.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
int id = v.getId();
/*Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + arrPath[id]), "image/*");
startActivity(intent);
*/
Intent intent = getIntent();
Uri data = intent.getData();
//Check If data type is Image
if (intent.getType().indexOf("image/") == id)
{
//imageview.setImageURI(data);
ImageView imge = (ImageView)findViewById(R.id.result);
imge.setImageURI(data);
}
}
});
holder.imageview.setImageBitmap(thumbnails[position]);
holder.checkbox.setChecked(thumbnailsselection[position]);
holder.id = position;
return convertView;
}
}
class ViewHolder {
ImageView imageview;
CheckBox checkbox;
int id;
} }
Android Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mygallary"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme"
android:configChanges="orientation|keyboardHidden" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<data android:mimeType="image/*" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="image/*" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.SEND" />
<data android:mimeType="image/*" />
</intent-filter>
</activity>
</application>
更改代码后
public class MainActivity extends Activity {
private int count;
private Bitmap[] thumbnails;
private boolean[] thumbnailsselection;
private String[] arrPath;
private ImageAdapter imageAdapter;
File file = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
show();
final Button selectBtn = (Button) findViewById(R.id.selectBtn);
final Button shareBtn = (Button) findViewById(R.id.btnShare);
//delete image.
selectBtn.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
final int len = thumbnailsselection.length;
int cnt = 0;
String selectImages = "";
for (int i =0; i<len; i++)
{
if (thumbnailsselection[i])
{
cnt++;
selectImages = selectImages + arrPath[i] +" | ";
file= new File(arrPath[i]);
if(file.exists())
{
file.delete();
imageAdapter.notifyDataSetChanged();
Log.v("roni", selectImages);
//arrPath[i] = null;
//selectImages = null;
Log.v("roni", arrPath[i]);
}
}
}
if (cnt == 0){
Toast.makeText(getApplicationContext(),
"Please select at least one image",
Toast.LENGTH_LONG).show();
} else
{
//thumbnails= null;
imageAdapter.notifyDataSetChanged();
show();
Toast.makeText(getApplicationContext(),cnt +" Images Deleted ",Toast.LENGTH_LONG).show();
Log.v("SelectedImages", selectImages);
}
}
});
//share image.
shareBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND_MULTIPLE);
final int len = thumbnailsselection.length;
int cnt = 0;
ArrayList<Uri> imageUris = new ArrayList<Uri>();
Uri path= null;
String selectImages = "";
for (int i =0; i<len; i++)
{
if (thumbnailsselection[i])
{
cnt++;
selectImages = selectImages + arrPath[i] +" | ";
Log.v("roni", selectImages);
path = Uri.parse(arrPath[i]);
imageUris.add(path);
}
}
if (cnt == 0){
Toast.makeText(getApplicationContext(),
"Please select at least one image",
Toast.LENGTH_LONG).show();
} else
{
Log.v("roni", selectImages);
Toast.makeText(getApplicationContext(),cnt +" Images shared ",Toast.LENGTH_SHORT).show();
Log.d("SelectedImages", selectImages);
}
shareIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, imageUris);
shareIntent.setType("image/*");
startActivity(Intent.createChooser(shareIntent, "Share images to.."));
startActivity(shareIntent);
}
});
show();
}
public void show() {
//stored data
final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
final String orderBy = MediaStore.Images.Media._ID;
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.thumbnails = new Bitmap[this.count];
this.arrPath = new String[this.count];
this.thumbnailsselection = new boolean[this.count];
//move image
for (int i = 0; i < this.count; i++) {
imagecursor.moveToPosition(i);
int id = imagecursor.getInt(image_column_index);
int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
thumbnails[i] = MediaStore.Images.Thumbnails.getThumbnail(getApplicationContext().getContentResolver(), id,
MediaStore.Images.Thumbnails.MINI_KIND, null);
arrPath[i]= imagecursor.getString(dataColumnIndex);
}
GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);
imageAdapter = new ImageAdapter();
imagegrid.setAdapter(imageAdapter);
imagecursor.close();
}
public class ImageAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public ImageAdapter() {
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) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.galleryitem, null);
holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.itemCheckBox);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
holder.checkbox.setId(position);
holder.imageview.setId(position);
holder.checkbox.setOnClickListener(new 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.imageview.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
int id = v.getId();
/*Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + arrPath[id]), "image/*");
startActivity(intent);
*/
/*Intent intent = getIntent();
Uri data = intent.getData();
//Check If data type is Image
if (intent.getType().indexOf("image/") == id)
{
//imageview.setImageURI(data);
ImageView imge = (ImageView)findViewById(R.id.result);
imge.setImageURI(data);
}*/
}
});
holder.imageview.setImageBitmap(thumbnails[position]);
holder.checkbox.setChecked(thumbnailsselection[position]);
holder.id = position;
return convertView;
}
}
class ViewHolder {
ImageView imageview;
CheckBox checkbox;
int id;
}
}
在调用notifyDataSetChanged();之前你应该从thumbnails中删除已删除的图像
Bitmap[] array. but if you can use List<Bitmap> instead of that, the method will be like this :
public void RemoveThumbnail(int position)
{
this.thumbnails.remove(position);
//notifyDataSetChanged() can be called in this method or after
//calling this method in MainActivity
notifyDataSetChanged();
}
否则这是删除特定位置缩略图的东西：
public void RemoveThumbnail(int position)
{
Bitmap[] temp = new Bitmap[thumbnails.length - 1];
int tempIndex = 0;
for (int i = 0 ; i < thumbnails.lenght ; i++)
{
if(i != position)
temp[tempIndex ++] = thumbnails[i];
}
thumbnails = temp;
//notifyDataSetChanged() can be called in this method or after
//calling this method in MainActivity
notifyDataSetChanged();
}
你应该通知你的适配器。
首先在代码顶部（onClickListeners之前）声明你的适配器（imageAdapter），然后在你改变某些东西时调用它（例如在删除onClickListener中的照片后）：
imageAdapter.notifyDataSetChanged();
删除文件后尝试发送广播。在Kotlin你可以做到：
private fun deleteImage(path: String) {
val fDelete = File(path)
if (fDelete.exists()) {
if (fDelete.delete()) {
MediaScannerConnection.scanFile(this, arrayOf(Environment.getExternalStorageDirectory().toString()), null) { _, _ ->
Log.d("debug", "DELETE FILE DONE")
finish()
}
}
}
}