Question

我正在尝试从API下载zip文件。为此，我使用以下代码：

public class Download_Activity extends Activity {

public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;

/**
 * Called when the activity is first created.
 */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.download);
    startBtn = (Button) findViewById(R.id.downloadButton);

    startBtn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            startDownload();
        }
    });
}

private void startDownload() {
    String url = downloadURL;
    new DownloadFileAsync().execute(url);
}

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
        case DIALOG_DOWNLOAD_PROGRESS:
            mProgressDialog = new ProgressDialog(this);
            mProgressDialog.setMessage("Downloading file..");
            mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            mProgressDialog.setCancelable(false);
            mProgressDialog.show();
            return mProgressDialog;
        default:
            return null;
    }
}

class DownloadFileAsync extends AsyncTask<String, String, String> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        showDialog(DIALOG_DOWNLOAD_PROGRESS);
    }

    @Override
    protected String doInBackground(String... aurl) {
        int count;

        try {

            URL url = new URL(aurl[0]);
            URLConnection urlConnection = url.openConnection();
            urlConnection.setDoOutput(true);
            urlConnection.connect();

            Log.i("1111", "1111" );
            File SDCardRoot = Environment.getExternalStorageDirectory();
            File file = new File(SDCardRoot, "hello1.zip");
            Log.i("2222", "2222" );
            FileOutputStream fileOutput = new FileOutputStream(file);
            InputStream inputStream = urlConnection.getInputStream();
            int totalSize = urlConnection.getContentLength();
            int downloadedSize = 0;
            byte[] buffer = new byte[1024];
            int bufferLength = 0;
            Log.i("3333", "3333" );
            Log.i("befferLength", "bufferLength: " + bufferLength);
            Log.i("is read buffer", "is read buffer: " + inputStream.read(buffer));
            while ((bufferLength = inputStream.read(buffer)) > 0) {
                Log.i("inside while", "inside while ");
                fileOutput.write(buffer, 0, bufferLength);
                downloadedSize += bufferLength;
                updateProgress(downloadedSize, totalSize);
            }
            Log.i("4444", "4444" );
            fileOutput.close();

        } catch (Exception e) {
        }
        return null;


    }

    protected void onProgressUpdate(String... progress) {
        Log.d("ANDRO_ASYNC", progress[0]);
        mProgressDialog.setProgress(Integer.parseInt(progress[0]));
    }

    @Override
    protected void onPostExecute(String unused) {
        dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
    }
}

public void updateProgress(int currentSize, int totalSize) {
    Toast.makeText(getApplicationContext(), "Loading Files...",
            Toast.LENGTH_SHORT).show();
}

在此代码中，zip文件创建为“hello1.zip”，但此文件在我的手机中为空。这里我有各种日志语句来查找代码的执行。令我惊讶的是“Log.i（”2222“，”2222“）;”在打印其余日志时打印。你能告诉我问题是什么吗？

提前致谢..！

Answer 1

U可以使用DownloadManager类来处理暂停并在网络可用的情况下继续下载，并且您可以运行广播接收器以在下载完成时执行操作（如推送通知等） http://developer.android.com/reference/android/app/DownloadManager.html

Android下载一个Zip文件

1 个答案: