我知道这个问题很熟悉,但我需要帮助。我不知道为什么我的复选框变成了一个空指针。到目前为止,我在这里:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gallery_image);
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];
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.MICRO_KIND, null);
arrPath[i]= imagecursor.getString(dataColumnIndex);
}
final GridView imagegrid = (GridView) findViewById(R.id.grid_GalleryImage);
imageAdapter = new ImageAdapter();
imagegrid.setAdapter(imageAdapter);
// Check All
Button btnCheckAll = (Button) findViewById(R.id.btn_SelectAll);
btnCheckAll.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
int count = thumbnails.length;
for (int i = 0; i < count; i++) {
LinearLayout itemLayout = (LinearLayout)imagegrid.getChildAt(i); // Find by under LinearLayout
CheckBox checkbox = (CheckBox)itemLayout.findViewById(R.id.cbo_CheckImage);
checkbox.setChecked(true);
}
}
});
这是我在另一个 xml 中获取复选框的类。请帮我解决这个问题,我在这里堆了一天。
public class ImageAdapter extends BaseAdapter {
private LayoutInflater mInflater;
ViewHolder holder;
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) {
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(
R.layout.gallery, null);
holder.imageview = (ImageView) convertView.findViewById(R.id.img_thumbImage);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.cbo_CheckImage);
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) {
// TODO Auto-generated method stub
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) {
// TODO Auto-generated method stub
int id = v.getId();
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + arrPath[id]), "image/*");
startActivity(intent);
}
});
holder.imageview.setImageBitmap(thumbnails[position]);
holder.checkbox.setChecked(thumbnailsselection[position]);
holder.id = position;
return convertView;
}
}
class ViewHolder {
CheckBox checkbox;
ImageView imageview;
int id;
}