While 语句导致代码无法执行

Question

我设置的 while 语句导致它下面的代码无法执行。

当我在这里使用此代码时：

while ((count = is.read(data)) != -1) {
            total += count;

            publishProgress("" + (int) ((total * 100) / lenghtOfFile));

        }

要更新文件下载的进度对话框，我需要的其他代码没有被执行。

我不确定为什么会这样，如果有人可以解释和帮助，那就太好了。

完整代码：

public class SetWallpaperAsync extends AsyncTask<String, String, String> {
private Context context;
private ProgressDialog pDialog;
String image_url;
URL mImageUrl;
String myFileUrl1;
Bitmap bmImg = null;

public SetWallpaperAsync(Context context) {
    this.context = context;
}

@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub

    super.onPreExecute();

    pDialog = new ProgressDialog(context);
    pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    pDialog.setMessage("Downloading Image...");
    pDialog.setIndeterminate(false);
    pDialog.setCancelable(false);
    pDialog.show();
pDialog.setMax(100);
}

@Override
protected String doInBackground(String... args) { 
    // TODO Auto-generated method stub

    InputStream is = null;

    int count;

    try {

        mImageUrl = new URL(args[0]);
        // myFileUrl1 = args[0];

        HttpURLConnection conn = (HttpURLConnection) mImageUrl
                .openConnection();
        conn.setDoInput(true);
        conn.connect();
        is = conn.getInputStream();
        int lenghtOfFile = conn.getContentLength();
        byte data[] = new byte[1024];
        long total = 0;



        while ((count = is.read(data)) != -1) {
            total += count;

            publishProgress("" + (int) ((total * 100) / lenghtOfFile));

        }


        //This code doesn't get executed when using the code above
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Config.RGB_565;
        bmImg = BitmapFactory.decodeStream(is, null, options);

    } catch (IOException e) {
        e.printStackTrace();
    }

    finally {

        if (is != null) {
            try {
                is.close();
            } catch (Exception e) {
            }
        }
    }

    return null;
}

protected void onProgressUpdate(String... progress) {

    pDialog.setProgress(Integer.parseInt(progress[0]));
}

@Override
protected void onPostExecute(String args) {
    // TODO Auto-generated method stub

    if (bmImg == null) {

        Toast.makeText(context, "Image still loading...",
                Toast.LENGTH_SHORT).show();

        pDialog.dismiss();

    }

    else {

        WallpaperManager wpm = WallpaperManager.getInstance(context);
        try {
            wpm.setBitmap(bmImg);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        pDialog.dismiss();

        Toast.makeText(context, "Wallpaper Successfully Set!",
                Toast.LENGTH_SHORT).show();

    }
}
}

Answer 1

您的while 循环会消耗所有输入，即直到到达-1 流结束。

当您在此处尝试从同一流中解码位图时：

bmImg = BitmapFactory.decodeStream(is, null, options);

...没有什么可以解码的。

Answer 2

循环中可能有一些异常：

while ((count = is.read(data)) != -1) {
            total += count;

            publishProgress("" + (int) ((total * 100) / lenghtOfFile));

        }

这导致其余代码未执行。

检查catch statement是否有一些异常或调试代码流以识别实际问题。

Answer 3

您需要将最大进度设置为内容长度...

protected String doInBackground(String... args) {
    ..........
    final int contentLength = conn.getContentLength();
    runOnUiThread(new Runnable() {

        @Override
        public void run() {
            pDialog.setMax(contentLength);
        }
    });
    .........
}