Question

我正在尝试使用水平进度条下载图像，然后将其存储在SD卡中的文件中，代码如下：

  package com.erc.library;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;

import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class Splashscreen extends Activity {

    ProgressBar pd;
    String a="";
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.splashscreen);

        pd=(ProgressBar)findViewById(R.id.progressBar1);
        pd.setMax(100);




        new ProgressTask().execute();
    }


    private class ProgressTask extends AsyncTask <String,String,String>
    {

        @Override
        protected void onPreExecute()
        {

             pd.setIndeterminate(false);
             pd.setMax(100);
             Toast.makeText(getBaseContext(),a,Toast.LENGTH_LONG).show();
        }


        @Override
        protected void onProgressUpdate(String... progress) {

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


        protected void onPostExecute(Void result) 
        {
            Toast.makeText(getBaseContext(),"done",Toast.LENGTH_LONG).show();
        }

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

            ///////////////////////////////////////////////////////////////////////////////////////////////////////
             try
                {
                    URL url = new URL("http://mylink/myimage.png");

                    URLConnection ucon = url.openConnection();
//                  ucon.setReadTimeout(15000);
//                  ucon.setConnectTimeout(30000);

                    InputStream is = ucon.getInputStream();
                    int lenghtOfFile = ucon.getContentLength();
                    BufferedInputStream inStream = new BufferedInputStream(is, 1024 * 5);

                    String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath()+"/library";
                    String fileName = "test.png";

                    // Not sure if the / is on the path or not
                    File file = new File(baseDir + File.separator + fileName);



                //    File file = new File(this.getDir(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Sayegh library", Context.MODE_PRIVATE) + "/yourfile.png");

                    if (file.exists())
                    {
                        file.delete();
                    }
                    file.createNewFile();

                    FileOutputStream outStream = new FileOutputStream(file);
                    byte[] buff = new byte[5 * 1024];

                    int len;
                    byte data[] = new byte[1024];
                       long total = 0;
                    while ((len = inStream.read(buff)) != -1)
                    {
                        total += len;
                          // publishing the progress....
                          // After this onProgressUpdate will be called
                     //  pd.setProgress((int) ((total * 100) / lenghtOfFile));
                      //    publishProgress("" + (int) ((total * 100) / lenghtOfFile));
                        outStream.write(buff, 0, len);
                    }

                    outStream.flush();
                    outStream.close();
                    inStream.close();

                }
                catch (Exception e)
                {
                a=e.toString(); 

                }

            ///////////////////////////////////////////////////////////////////////////////////////////////////////



            return null;

        }


    }

}

进度条没有显示任何进度，图片没有下载，请帮忙吗？

Answer 1

看起来您需要设置权限。如果没有帮助，请阅读adb logcat输出并在此处发布相关部分。

Android水平进度条在下载图像时无法正常工作

1 个答案: