java - 无法将字节转换为 KB

Question

我有一个 android 视频播放器，它显示 SD 卡上的所有视频名称和文件大小，但大小以字节显示，我无法将它转换为 KB、MB、GB 等。我尝试除以 int值增加 1024 但它不起作用。它打印出错误的值。谁能帮忙？

SDVideos.java

import android.app.Activity;
import android.content.ContentResolver;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import java.text.DecimalFormat;

public class SDVideos extends Activity
{
    private Cursor videoCursor;
    int videoColumnIndex;
    ListView videolist;
    int count;

    String[] thumbColumns = { MediaStore.Video.Thumbnails.DATA,MediaStore.Video.Thumbnails.VIDEO_ID };
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sdvideos);
        initialization();
    }

    private void initialization()
    {
        System.gc();
        String[] videoProjection = { MediaStore.Video.Media._ID,MediaStore.Video.Media.DATA,
                MediaStore.Video.Media.DISPLAY_NAME,MediaStore.Video.Media.SIZE };
        videoCursor =getContentResolver().query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI,videoProjection, null, null, null);
        count = videoCursor.getCount();
        videolist = (ListView) findViewById(R.id.PhoneVideoList);

        videolist.setAdapter(new VideoListAdapter(this.getApplicationContext()));
        videolist.setOnItemClickListener(videogridlistener);
    }

    private AdapterView.OnItemClickListener videogridlistener = new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView parent, View v, int position, long id)
        {
            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA);
            videoCursor.moveToPosition(position);
            String filename = videoCursor.getString(videoColumnIndex);
            Log.i("FileName: ", filename);
//Intent intent = new Intent(VideoActivity.this, ViewVideo.class);
//intent.putExtra("videofilename", filename);
//startActivity(intent);
        }};

    public class VideoListAdapter extends BaseAdapter
    {
        private Context vContext;

        public VideoListAdapter(Context c)
        {
            vContext = c;
        }

        public int getCount()
        {
            return videoCursor.getCount();
        }

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

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

        public View getView(int position, View convertView, ViewGroup parent)
        {
            View listItemRow;
            listItemRow = LayoutInflater.from(vContext).inflate(R.layout.listitem, parent, false);

            TextView txtTitle = (TextView)listItemRow.findViewById(R.id.txtTitle);
            TextView txtSize = (TextView)listItemRow.findViewById(R.id.txtSize);
            ImageView thumbImage = (ImageView)listItemRow.findViewById(R.id.imgIcon);

            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME);
            videoCursor.moveToPosition(position);
            txtTitle.setText(videoCursor.getString(videoColumnIndex));

            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE);
            videoCursor.moveToPosition(position);
            txtSize.setText(" Size(KB):" + (videoCursor.getString(videoColumnIndex/205870)));


            int videoId = videoCursor.getInt(videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));
            ContentResolver crThumb = getContentResolver();
            BitmapFactory.Options options=new BitmapFactory.Options();
            options.inSampleSize = 1;
            Bitmap curThumb = MediaStore.Video.Thumbnails.getThumbnail(crThumb, videoId, MediaStore.Video.Thumbnails.MICRO_KIND, options);
            thumbImage.setImageBitmap(curThumb);
            return listItemRow;
        }
    }

}

列表项。 xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp">

    <ImageView android:id="@+id/imgIcon"
        android:layout_width="90dip"
        android:layout_height="90dip"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"/>

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginRight="10dip">

        <TextView android:id="@+id/txtTitle"
            android:layout_width="250dip"
            android:layout_height="wrap_content"
            android:gravity="left"
            android:textStyle="normal"
            android:textSize="15dp"
            android:textColor="#FF0000"
            android:paddingTop="30dp"
            android:paddingLeft="20dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="5dp" />

        <TextView android:id="@+id/txtSize"
            android:layout_width="250dip"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="20dp"
            android:paddingTop="20dp"
            android:textStyle="italic"
            android:textSize="12dp"
            android:textColor="#00FF00" />
    </LinearLayout>
</LinearLayout>

Answer 1

可以先使用length方法获取文件的大小。然后这样做 -

videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE);

long fileSizeInBytes = videoCursor.getLong(videoColumnIndex)
// Convert the bytes to Kilobytes (1 KB = 1024 Bytes)
long fileSizeInKB = fileSizeInBytes / 1024;
// Convert the KB to MegaBytes (1 MB = 1024 KBytes)
long fileSizeInMB = fileSizeInKB / 1024;