[置顶] Android上传文件到Web服务器，PHP接收文件（二）

接上一篇文章《Android上传文件到Web服务器，PHP接收文件（一）》，这次在之前的基础上添加进度显示，Java代码如下所示：

package com.lenovo.uptest; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.net.HttpURLConnection; import java.net.URL; import android.app.Activity; import android.app.AlertDialog; import android.app.ProgressDialog; import android.content.DialogInterface; import android.os.AsyncTask; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TextView; public class UploadtestActivity extends Activity { /** Called when the activity is first created. */ /** * Upload file to web server with progress status, client: android; * server:php * **/ private TextView mtv1 = null; private TextView mtv2 = null; private Button bupload = null; private String uploadFile = "/sdcard/testimg.jpg"; private String actionUrl = "http://10.100.1.208/receive_file.php"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mtv1 = (TextView) findViewById(R.id.mtv1); mtv1.setText("文件路径：\n" + uploadFile); mtv2 = (TextView) findViewById(R.id.mtv2); mtv2.setText("上传地址：\n" + actionUrl); bupload = (Button) findViewById(R.id.bupload); bupload.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub FileUploadTask fileuploadtask = new FileUploadTask(); fileuploadtask.execute(); } }); } // show Dialog method private void showDialog(String mess) { new AlertDialog.Builder(UploadtestActivity.this).setTitle("Message") .setMessage(mess) .setNegativeButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }).show(); } class FileUploadTask extends AsyncTask<Object, Integer, Void> { private ProgressDialog dialog = null; HttpURLConnection connection = null; DataOutputStream outputStream = null; DataInputStream inputStream = null; //the file path to upload String pathToOurFile = "/sdcard/testimg.jpg"; //the server address to process uploaded file String urlServer = "http://10.100.1.208/receive_file.php"; String lineEnd = "\r\n"; String twoHyphens = "--"; String boundary = "*****"; File uploadFile = new File(pathToOurFile); long totalSize = uploadFile.length(); // Get size of file, bytes @Override protected void onPreExecute() { dialog = new ProgressDialog(UploadtestActivity.this); dialog.setMessage("正在上传..."); dialog.setIndeterminate(false); dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); dialog.setProgress(0); dialog.show(); } @Override protected Void doInBackground(Object... arg0) { long length = 0; int progress; int bytesRead, bytesAvailable, bufferSize; byte[] buffer; int maxBufferSize = 256 * 1024;// 256KB try { FileInputStream fileInputStream = new FileInputStream(new File( pathToOurFile)); URL url = new URL(urlServer); connection = (HttpURLConnection) url.openConnection(); // Set size of every block for post connection.setChunkedStreamingMode(256 * 1024);// 256KB // Allow Inputs & Outputs connection.setDoInput(true); connection.setDoOutput(true); connection.setUseCaches(false); // Enable POST method connection.setRequestMethod("POST"); connection.setRequestProperty("Connection", "Keep-Alive"); connection.setRequestProperty("Charset", "UTF-8"); connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary); outputStream = new DataOutputStream( connection.getOutputStream()); outputStream.writeBytes(twoHyphens + boundary + lineEnd); outputStream .writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + pathToOurFile + "\"" + lineEnd); outputStream.writeBytes(lineEnd); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); buffer = new byte[bufferSize]; // Read file bytesRead = fileInputStream.read(buffer, 0, bufferSize); while (bytesRead > 0) { outputStream.write(buffer, 0, bufferSize); length += bufferSize; progress = (int) ((length * 100) / totalSize); publishProgress(progress); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); bytesRead = fileInputStream.read(buffer, 0, bufferSize); } outputStream.writeBytes(lineEnd); outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd); publishProgress(100); // Responses from the server (code and message) int serverResponseCode = connection.getResponseCode(); String serverResponseMessage = connection.getResponseMessage(); /* 将Response显示于Dialog */ // Toast toast = Toast.makeText(UploadtestActivity.this, "" // + serverResponseMessage.toString().trim(), // Toast.LENGTH_LONG); // showDialog(serverResponseMessage.toString().trim()); /* 取得Response内容 */ // InputStream is = connection.getInputStream(); // int ch; // StringBuffer sbf = new StringBuffer(); // while ((ch = is.read()) != -1) { // sbf.append((char) ch); // } // // showDialog(sbf.toString().trim()); fileInputStream.close(); outputStream.flush(); outputStream.close(); } catch (Exception ex) { // Exception handling // showDialog("" + ex); // Toast toast = Toast.makeText(UploadtestActivity.this, "" + // ex, // Toast.LENGTH_LONG); } return null; } @Override protected void onProgressUpdate(Integer... progress) { dialog.setProgress(progress[0]); } @Override protected void onPostExecute(Void result) { try { dialog.dismiss(); // TODO Auto-generated method stub } catch (Exception e) { } } } }

       服务器端仍然和之前的一样。

        这里使用了AsyncTask，它使创建需要与用户界面交互的长时间运行的任务变得更简单，适用于简单的异步处理，不需要借助线程和Handler即可实现。
        AsyncTask是抽象类.AsyncTask定义了三种泛型类型 Params，Progress和Result。
　　Params 启动任务执行的输入参数，比如HTTP请求的URL。
　　Progress 后台任务执行的百分比。
　　Result 后台执行任务最终返回的结果，比如String。

        AsyncTask的执行分为四个步骤，每一步都对应一个回调方法，这些方法不应该由应用程序调用，开发者需要做的就是实现这些方法。
　　1) 子类化AsyncTask
　　2) 实现AsyncTask中定义的下面一个或几个方法
　　onPreExecute(), 该方法将在执行实际的后台操作前被UI thread调用。可以在该方法中做一些准备工作，如在界面上显示一个进度条。
　　doInBackground(Params...), 将在onPreExecute 方法执行后马上执行，该方法运行在后台线程中。这里将主要负责执行那些很耗时的后台计算工作。可以调用 publishProgress方法来更新实时的任务进度。该方法是抽象方法，子类必须实现。
　　onProgressUpdate(Progress...),在publishProgress方法被调用后，UI thread将调用这个方法从而在界面上展示任务的进展情况，例如通过一个进度条进行展示。
　　onPostExecute(Result), 在doInBackground 执行完成后，onPostExecute 方法将被UI thread调用，后台的计算结果将通过该方法传递到UI thread.

        为了正确的使用AsyncTask类，以下是几条必须遵守的准则：
　　1) Task的实例必须在UI thread中创建
　　2) execute方法必须在UI thread中调用
　　3) 不要手动的调用onPreExecute(), onPostExecute(Result)，doInBackground(Params...), onProgressUpdate(Progress...)这几个方法
　　4) 该task只能被执行一次，否则多次调用时将会出现异常
        doInBackground方法和onPostExecute的参数必须对应，这两个参数在AsyncTask声明的泛型参数列表中指定，第一个为doInBackground接受的参数，第二个为显示进度的参数，第三个为doInBackground返回和onPostExecute传入的参数。

运行结果如下：