Question

我有一个ImageView，我从服务器获取它的内容，有人将其发送到服务器。我想改变照片的大小以适合我想要的;为此，我成功了，我可以调整它，但问题是它降低了图像质量，因为我将该照片发送到另一个活动，因此我需要图像的原始质量。下面我将发布课程，希望你能帮助我：

     public class welcome extends ActionBarActivity {

     @Override
       protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_welcome);

make_category_list();

clearCache();

lv = (ListView) findViewById(R.id.ads_list);
make_all_ads_list();

lv.setOnScrollListener(new AbsListView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(AbsListView view, int i) {
        if (i == 1) {

            if (view.getId() == lv.getId()) {
                int currentFirstVisibleItem = lv.getFirstVisiblePosition();
                int mLastFirstVisibleItem = lv.getLastVisiblePosition();

                if (currentFirstVisibleItem > mLastFirstVisibleItem)
                {
                } else if (currentFirstVisibleItem < mLastFirstVisibleItem) {
                    // go down
                    if (goNext == true) {
                        goNext = false;
                        make_all_ads_list();

                        pDialog.dismiss();
                    }
                }

            }

        }
    }

    @Override
    public void onScroll(AbsListView absListView, int i, int i1, int i2)
    {

    }
});

lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {

        Intent intent = new Intent(getApplicationContext(), show_full_ads.class);
        intent.putExtra("ads", all_ads.get(position));
        startActivity(intent);

    }
});
   }

  @Override
protected void onDestroy() {
super.onDestroy();

clearCache();
}

 public void make_all_ads_list() {
try
{

    DownloadTask dl = new DownloadTask();

    dl.execute(url_ads + current_page);

    current_page++;
}
catch (Exception e)
{
    Log.i("NaqibMessage", "error in ads Class in method make_all_ads_list -> " + e.toString());
}
}

 private class DownloadTask extends AsyncTask<String, Void, String>
 {
@Override
protected void onPreExecute() {
    super.onPreExecute();
    pDialog = new ProgressDialog(welcome.this);
    pDialog.setMessage("درحال آماده سازی");
    pDialog.setCancelable(false);
    pDialog.show();
}

@Override
protected String doInBackground(String... params) {
    String temp = "";

    try {
        JSONDownloader jd = new JSONDownloader();

        temp = jd.downloadURL(params[0]);
    }
    catch (Exception e)
    {
        Log.i("NaqibMessage", "error in ads Class in DownloadTask -> " + e.toString());
    }
    return (temp);
}

@Override
protected void onPostExecute(String s)
{
    ListViewLoaderTask loader = new ListViewLoaderTask();
    loader.execute(s);

    pDialog.dismiss();

}
 }


  private class ListViewLoaderTask extends AsyncTask<String, Void,  SimpleAdapter> {

@Override
protected SimpleAdapter doInBackground(String... params)
{

    try
    {
        AdsParser parser = new AdsParser();
        all_ads.addAll(parser.parse(params[0]));
    }
    catch (Exception e)
    {
        Log.i("NaqibMessage", "error in ads Class in ListViewLoaderTask-> " + e.toString());
    }

    String[] from = {"image", "title", "intro", "date"};

    int[] to = {R.id.ads_img, R.id.ads_title, R.id.ads_intro, R.id.ads_date};

    SimpleAdapter adb = new SimpleAdapter(getBaseContext(), all_ads, R.layout.ads_list_row, from, to);

    return adb;

}

@Override
protected void onPostExecute(SimpleAdapter adapter) {
    lv.setAdapter(adapter);

    for (int i = 0; i < adapter.getCount(); i++) {
        HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);

        String imgURL = (String) hm.get("image_path");

        HashMap<String, Object> forDownload = new HashMap<>();

        forDownload.put("image_path", imgURL);
        forDownload.put("position", i);

        ImageDownloaderTask imageDownloader = new ImageDownloaderTask();

        imageDownloader.execute(forDownload);
    }
    goNext = true;
}
}


      private class ImageDownloaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>> {
@Override
protected HashMap<String, Object> doInBackground(HashMap<String, Object>... params) {
    InputStream myStream;

    String imgURL = (String) params[0].get("image_path");
    int position = (Integer) params[0].get("position");

    try {
        URL url = new URL(imgURL);

        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

        connection.setDoInput(true);

        connection.connect();

        myStream = connection.getInputStream();

        File cacheDirectory = getBaseContext().getCacheDir();

        File temp = new File(cacheDirectory.getPath() + "/image_" + position + "_" + current_page + ".png");

        FileOutputStream outStream = new FileOutputStream(temp);

        Bitmap b = BitmapFactory.decodeStream(myStream);

        //Bitmap resizedBmp = Bitmap.createScaledBitmap(b, 140, 150, true);

        b.compress(Bitmap.CompressFormat.PNG, 100, outStream);

        outStream.flush();

        outStream.close();

        HashMap<String, Object> bitmap = new HashMap<>();

        bitmap.put("image", temp.getPath());
        bitmap.put("position", position);

        return (bitmap);

    } catch (Exception e) {
        /*
        Log.i("NaqibMessage" , "error in ads Class in ImageDownloaderTask -> " + e.toString());
        */
    }
    return null;
}

@Override
protected void onPostExecute(HashMap<String, Object> result) {
    String image = (String) result.get("image");

    int position = (Integer) result.get("position");

    SimpleAdapter adb = (SimpleAdapter) lv.getAdapter();

    HashMap<String, Object> hm = (HashMap<String, Object>) adb.getItem(position);

    hm.put("image", image);

    adb.notifyDataSetChanged();
}
 }

public void clearCache() {
try {
    File[] f = getBaseContext().getCacheDir().listFiles();

    for (File file : f) {
        file.delete();
    }
} catch (Exception e) {
    Log.i("NaqibMessage", "error in ads Class in ClearCache -> " + e.toString());

}
}

我删除了不必要的代码，你可以看到当我点击LIstView项目时我用它发送数据，在代码的最后部分你可以看到ImageDownloader类。

Answer 1

我可以在保留原始图像的同时调整图像大小吗？

是：

步骤1：将原始图像下载到一个文件中。

步骤2：调整已下载的图像的大小，如果需要，将输出写入第二个文件。

在不降低质量的情况下更改图像的高度和宽度

1 个答案: