/*長按gallery中的圖片進行刪除該圖片的操作*/
gallery.setOnItemLongClickListener(new OnItemLongClickListener(){

@Override
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
final int arg2, long arg3) {
// TODO Auto-generated method stub
new AlertDialog.Builder(SdcardActivity.this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("溫馨提示")
.setMessage("您真的要刪除這個圖片嗎")
.setPositiveButton("確定", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
File file=new File(Constants.path+imageNames[arg2]);
if(file.exists()){
file.delete();
}
}
})
.setNegativeButton("取消", null)
.show();
return true;
}

});
}