安卓处理器

Question

我正在使用 AlertDialog 显示文件中的图像，但是当我按下按钮显示对话框时，应用停止卡住 6 秒，然后显示警报对话框。

我的代码:

listView_prev.setOnItemClickListener(new AdapterView.OnItemClickListener() {


        @Override
        public void onItemClick(AdapterView<?> arg0, final View arg1, int arg2, long arg3) {
            //listview click event handling
            TextView id = (TextView) arg1.findViewById(R.id.textView17);
            final int id_To_Search = Integer.valueOf(id.getText().toString());
            Cursor item=mydb.singlecons(id_To_Search);
            Cursor att=mydb.attrs(id_To_Search);
            Cursor picloc=mydb.singleconspic(id_To_Search);
            att.moveToFirst();
            List<String> list = new ArrayList<>();
            //  Log.d("temp",att.getColumnName(1));

            while (!att.isAfterLast())
            {
                int l=att.getColumnCount();
                Log.d("length", String.valueOf(l));
                for(int i=2;i<l;i++){
                    Log.d("for","for");
                    if(att.getString(i)!=null){
                        String b= att.getColumnName(i)+" "+att.getString(i);
                        list.add(b);
                        Log.d("att",b);
                    }
                }
                Log.d("while","while");
                att.moveToNext();
            }
            att.close();
            Log.d("list", String.valueOf(list));
            picloc.moveToFirst();

            FilePathStrings = new String[picloc.getCount()];
            int i=0;
            while (!picloc.isAfterLast()){
                Log.d("picloc",picloc.getString(2));
                FilePathStrings[i]=picloc.getString(2);
                i++;
                picloc.moveToNext();
            }

            item.moveToFirst();

            AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(Consultation.this);
            LayoutInflater inflater = getLayoutInflater();
            View dialogView = inflater.inflate(R.layout.alert_label_editor, null);
            dialogBuilder.setView(dialogView);

            TextView con=(TextView)dialogView.findViewById(R.id.textView29);
            con.setText("Consultation on "+item.getString(4));
            TextView des=(TextView)dialogView.findViewById(R.id.textView28);
            des.setText(item.getString(2));
            TextView pre=(TextView)dialogView.findViewById(R.id.textView31);
            pre.setText(item.getString(3));
            TextView fee=(TextView)dialogView.findViewById(R.id.textView32);
            fee.setText(item.getString(5));
            adapter1 = new GridViewAdapter(FilePathStrings,getApplicationContext());
            grid = (GridView) dialogView.findViewById(R.id.gridview);
            grid.setAdapter(adapter1);
            grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                @Override
                public void onItemClick(AdapterView<?> parent, View view,
                                        int position, long id) {

                    Intent intent = new Intent();
                    intent.setAction(Intent.ACTION_VIEW);
                    intent.setDataAndType(Uri.parse("file://" + FilePathStrings[position]), "image/*");
                    startActivity(intent);
                }

            });
            AlertDialog alertDialog = dialogBuilder.create();
            alertDialog.show();

Gridviewadapter.java

class GridViewAdapter extends BaseAdapter {

private String[] filepath;
private static LayoutInflater inflater = null;
GridViewAdapter(String[] fpath,Context context) {
    filepath = fpath;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}
public int getCount() {
    return filepath.length;

}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}

public View getView(final int position, View convertView, ViewGroup parent) {
    View vi = convertView;
    if (convertView == null)
        vi = inflater.inflate(R.layout.gridview_item, null);
        ImageView image = (ImageView) vi.findViewById(R.id.image);
        Bitmap bmp = BitmapFactory.decodeFile(filepath[position]);

   Bitmap thumbBitmap = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(filepath[position]),320,240);

    image.setImageBitmap(thumbBitmap);

        return vi;
}
}

我该如何解决这个问题？我知道 handler 会在这里提供帮助，有人可以帮我解决这个问题吗？

Answer 1

I want the app to freeze for 6 seconds and then show the alert dialog

在 onItemClick 方法上，通过调用 singlecons,attrs,singleconspic 方法执行 3-4 次数据库操作，并从 Cursor 的 读取数据。这将在不执行任何操作的情况下显示 UI 线程。

建议是，使用 AsyncTask 而不是 Handler用于调用所有 DB 方法并从 Cursor 获取数据。

在将数据返回到 onPostExecute 之前等待 6 秒 doInBackground