Android 缩放位图后将其返回到hashmap时，无法解码流错误

在我的程序中，我使用SimpleAdapter将图像从SD卡显示到listview，但由于内存不足，文件太大，所以我尝试将图像缩放到较低的大小，为此我创建了一个单独的类文件

ThumbCreator.class

public Bitmap convertIntoThumb(String file_uri,String file_name)
{
    try
    {

    File f = new File(file_uri, file_name+".jpg");

    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;

    BitmapFactory.decodeStream(new FileInputStream(f),null,o);

    //The new size we want to scale to
    final int REQUIRED_SIZE=70;

    //Find the correct scale value. It should be the power of 2.
    int scale=1;
    while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE)
        scale*=2;

    //Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize=scale;

    Bitmap bitmap = BitmapFactory.decodeStream(new FileInputStream(f), null, o2);

    FileOutputStream fOutStream = new FileOutputStream(new File(file_uri+"THUMB1_"+file_name+".jpg"));
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fOutStream);

    fOutStream.flush();
    fOutStream.close();

    return bitmap;
}


catch (FileNotFoundException e) 
{
    // TODO: handle exception
    return null;
}
catch (IOException e) 
{
    // TODO: handle exception
    return null;
}

}

    final ArrayList<HashMap<String, ?>> list = new ArrayList<HashMap<String,?>>();


    //***adding receipts from particular record to cursor.
    cursor = sqldb.rawQuery("select * from table_1 where record_name = '"+record_name+"'",null);
    curso.moveToFirst();

    while (curso.isAfterLast()!=true) 
    {
        HashMap<String, Object> hashmap_temp = new HashMap<String,Object>();

        hashmap_temp.put("name", cursor_receipt.getString(1));


        if(cursor.getString(7).toString() != "")
        {
            hashmap_temp.put("image",thumbcreator.convertIntoThumb(img_path_new,cursor_receipt.getString(7)));

        }

        list.add(hashmap_temp);

        cursor.moveToNext();
    }
    cursor.close();

    SimpleAdapter adptr_list;

    adptr_list = new SimpleAdapter(context_receipt, list, R.layout.activity_textview_receipt, new String[]{"image","name"},new int[]{R.id.img_receipt,R.id.tv_name});

    lv = (ListView)findViewById(R.id.lv);
    lv.setAdapter(adptr_list);

我将此位图直接返回到hashmap.put（）方法中的主活动类，如下所示

Main.class

public Bitmap convertIntoThumb(String file_uri,String file_name)
{
    try
    {

    File f = new File(file_uri, file_name+".jpg");

    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;

    BitmapFactory.decodeStream(new FileInputStream(f),null,o);

    //The new size we want to scale to
    final int REQUIRED_SIZE=70;

    //Find the correct scale value. It should be the power of 2.
    int scale=1;
    while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE)
        scale*=2;

    //Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize=scale;

    Bitmap bitmap = BitmapFactory.decodeStream(new FileInputStream(f), null, o2);

    FileOutputStream fOutStream = new FileOutputStream(new File(file_uri+"THUMB1_"+file_name+".jpg"));
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fOutStream);

    fOutStream.flush();
    fOutStream.close();

    return bitmap;
}


catch (FileNotFoundException e) 
{
    // TODO: handle exception
    return null;
}
catch (IOException e) 
{
    // TODO: handle exception
    return null;
}

}

    final ArrayList<HashMap<String, ?>> list = new ArrayList<HashMap<String,?>>();


    //***adding receipts from particular record to cursor.
    cursor = sqldb.rawQuery("select * from table_1 where record_name = '"+record_name+"'",null);
    curso.moveToFirst();

    while (curso.isAfterLast()!=true) 
    {
        HashMap<String, Object> hashmap_temp = new HashMap<String,Object>();

        hashmap_temp.put("name", cursor_receipt.getString(1));


        if(cursor.getString(7).toString() != "")
        {
            hashmap_temp.put("image",thumbcreator.convertIntoThumb(img_path_new,cursor_receipt.getString(7)));

        }

        list.add(hashmap_temp);

        cursor.moveToNext();
    }
    cursor.close();

    SimpleAdapter adptr_list;

    adptr_list = new SimpleAdapter(context_receipt, list, R.layout.activity_textview_receipt, new String[]{"image","name"},new int[]{R.id.img_receipt,R.id.tv_name});

    lv = (ListView)findViewById(R.id.lv);
    lv.setAdapter(adptr_list);

注意：在解码图像时，我没有收到此错误，因为它使用FileoutputStream将缩放图像保存到给定位置时没有任何问题。只有在将位图返回到main类中的hashmap时，我才会收到此错误

注意：我也可以给主图像提供字符串格式的直接路径，它可以工作，但如果图像太大（如下图所示），则会出现错误。

---

hashmap_temp.put（“image”，img_path_new+“/”+cursor_receive.getString（7）+.jpg”）

simpledapter

只能绑定int（资源id）或字符串

ImageView

的

bindView

实现使用对象的

toString

作为图像的路径

您可以做的是将thumb uri

file_uri+“THUMB1\u”+file_name+”.jpg“

放在地图中而不是位图中（同时，它将允许一次加载最少数量的位图，而不是全部位图）

将方法签名更改为

public String convertIntoThumb(String file_uri,String file_name)

并返回：

return file_uri+"THUMB1_"+file_name+".jpg";

---

但它将返回原始图像，对吗？我需要在“位图”对象中获得的缩放图像。您在

位图中拥有的是您在
fOutStream中写入的内容。因此，您在这个文件中拥有的是您想要的缩放位图。哦，对不起，我弄错了，我得到了它，我会尝试它是否工作，但实际上我不需要保存缩放图像，因为它会增加sd卡上的内存，我写fOutStream只是为了检查BitmapFactory.decodeStream（新文件输入流（f），null，o2）；给出了这个错误，有没有办法在不保存的情况下显示缩放图像？另一个选择是实现一个自定义适配器来处理位图对象。我发现很难使用自定义适配器我是Android编程新手，所以，现在你的回答帮了我很大的忙，非常感谢。