这是将图片从我的图库上传到服务器的代码，此代码正在运行。
但点击后退按钮加载。
现在我要问的是当我点击后退按钮它应该转到上一页并且上传应该停止。
我该怎么做？
这是我的代码：
package com.politicalmileage.chintamanvanga;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Set;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
public class ContributeToTheSite extends Activity implements OnClickListener{
private TextView messageText;
private Button uploadButton, btnselectpic;
private ImageView imageview;
private int serverResponseCode = 0;
private ProgressDialog dialog = null;
private String upLoadServerUri = null;
private String imagepath=null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.contributetothesite);
uploadButton = (Button)findViewById(R.id.uploadButton);
messageText = (TextView)findViewById(R.id.messageText);
btnselectpic = (Button)findViewById(R.id.button_selectpic);
imageview = (ImageView)findViewById(R.id.imageView_pic);
btnselectpic.setOnClickListener(this);
uploadButton.setVisibility(View.INVISIBLE);
uploadButton.setOnClickListener(this);
upLoadServerUri = "http://url";
}
@Override
public void onClick(View arg0) {
if(arg0==btnselectpic)
{
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Complete action using"), 1);
}
else if (arg0==uploadButton) {
dialog = ProgressDialog.show(ContributeToTheSite.this, "", "Uploading file...", true);
messageText.setText("uploading started.....");
new Thread(new Runnable() {
public void run() {
uploadFile(imagepath);
}
}).start();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1 && resultCode == RESULT_OK) {
//Bitmap photo = (Bitmap) data.getData().getPath();
Uri selectedImageUri = data.getData();
imagepath = getPath(selectedImageUri);
Bitmap bitmap=BitmapFactory.decodeFile(imagepath);
imageview.setImageBitmap(bitmap);
messageText.setText("Uploading file path:" +imagepath);
uploadButton.setVisibility(View.VISIBLE);
}
}
public String getPath(Uri uri) {
String[] projection = { MediaStore.Images.Media.DATA };
Cursor cursor = managedQuery(uri, projection, null, null, null);
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
}
public int uploadFile(String sourceFileUri) {
String fileName = sourceFileUri;
HttpURLConnection conn = null;
DataOutputStream dos = null;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
File sourceFile = new File(sourceFileUri);
if (!sourceFile.isFile()) {
dialog.dismiss();
Log.e("uploadFile", "Source File not exist :"+imagepath);
runOnUiThread(new Runnable() {
public void run() {
messageText.setText("Source File not exist :"+ imagepath);
}
});
return 0;
}
else
{
try {
// open a URL connection to the Servlet
FileInputStream fileInputStream = new FileInputStream(sourceFile);
URL url = new URL(upLoadServerUri);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true); // Allow Inputs
conn.setDoOutput(true); // Allow Outputs
conn.setUseCaches(false); // Don't use a Cached Copy
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("ENCTYPE", "multipart/form-data");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
conn.setRequestProperty("uploaded_file", fileName);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
+ fileName + "\"" + lineEnd);
dos.writeBytes(lineEnd);
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// Responses from the server (code and message)
serverResponseCode = conn.getResponseCode();
String serverResponseMessage = conn.getResponseMessage();
Log.i("uploadFile", "HTTP Response is : "
+ serverResponseMessage + ": " + serverResponseCode);
if(serverResponseCode == 200){
runOnUiThread(new Runnable() {
public void run() {
String msg = "File Upload Completed.\n\n Thanks for Your Contribution to the Mobile App";
messageText.setText(msg);
Toast.makeText(ContributeToTheSite.this, "Thanks for Your Contribution to the Mobile App.", Toast.LENGTH_SHORT).show();
finish();
}
});
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();
} catch (MalformedURLException ex) {
dialog.dismiss();
ex.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
messageText.setText("MalformedURLException Exception : check script url.");
Toast.makeText(ContributeToTheSite.this, "MalformedURLException", Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload file to server", "error: " + ex.getMessage(), ex);
} catch (Exception e) {
dialog.dismiss();
e.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
messageText.setText("Got Exception : see logcat ");
Toast.makeText(ContributeToTheSite.this, "Got Exception : see logcat ", Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload file to server Exception", "Exception : " + e.getMessage(), e);
}
dialog.dismiss();
return serverResponseCode;
} // End else block
}
}
答案 0 :(得分：0)
您可以覆盖活动的onBackPressed（）方法，以便在按下后退按钮时停止上传线程。
答案 1 :(得分：0)
你可以这样做
首先，您必须覆盖public void onBackPressed()方法。
else if (arg0==uploadButton) {
dialog = ProgressDialog.show(ContributeToTheSite.this, "", "Uploading file...", true);
messageText.setText("uploading started.....");
uploadThread = new Thread(new Runnable() {
public void run() {
uploadFile(imagepath);
}
}).start();
}
uploadThread在类或静态中定义，用于onBackPressed方法
之后，uploadThread.stop()在onBackPressed方法中。
public void onBackPressed(){
uploadThread.stop();
super.onBackPressed();
}
如果无法使用此方法，请尝试此操作。
public class ContributeToTheSite extends Activity implements OnClickListener{
private boolean sendingFile = false;
...
public void onClick(View arg0) {
if(arg0==btnselectpic)
{
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Complete action using"), 1);
}
else if (arg0==uploadButton) {
dialog = ProgressDialog.show(ContributeToTheSite.this, "", "Uploading file...", true);
messageText.setText("uploading started.....");
sendingFile = true;
new Thread(new Runnable() {
public void run() {
uploadFile(imagepath);
}
}).start();
}
}
public void onBackPressed(){
sendingFile = false;
super.onBackPressed();
}
public int uploadFile(String sourceFileUri) {
...
while (bytesRead > 0 && sendingFile ) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
if( !sendingFile ){
//to do send message server sending file is canceled.
return -1;
}
sendingFile = false;
...
...
答案 2 :(得分：0)
实际上你可以从下面定义的下面方法中断当前线程所以问题。 How to stop threads and handlers in Android
我认为不是创建线程而是必须使用asynctask并取消当前asynctask它很容易处理
asynctask cancel method java doc
答案 3 :(得分：0)
试试这个
public void onBackPressed() {
// Do Here what ever you want do on back press;
if (conn != null)
{
conn.disconnect();
}
finish();
}