我有这段代码用于将图像从android发送到服务器，它很有效！但有时它会让我回想起logcat中的一个错误：
Skipped 57 frames! The application may be doing too much work on its main thread
但我不知道只是有时，例如，当这种情况发生时，安装该应用程序的手机工作不好！
public class SendingImage extends Activity {
private static final int REQUEST_IMAGE = 100;
TextView tvPath;
TextView txtHaut;
ImageView preview;
File destination;
String imagePath;
ImageButton takePhoto;
Button btnCreate;
int serverResponseCode = 0;
ProgressDialog dialog = null;
String upLoadServerUri = null;
String name;
private static final int CAMERA_REQUEST = 1;
private static final int PICK_FROM_GALLERY = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sending_image);
preview = (ImageView) findViewById(R.id.imageViewPreview);
btnCreate = (Button) findViewById(R.id.bInviaFoto) ;
txtHaut = (TextView) findViewById(R.id.textViewEsito);
takePhoto = (ImageButton) findViewById(R.id.bCamera);
preview.setVisibility(View.GONE);
txtHaut.setVisibility(View.GONE);
upLoadServerUri = "http://fiezzo.altervista.org/upload_image.php";
name = dateToString(new Date(),"yyyyMMddhhmmss");
destination = new File(Environment.getExternalStorageDirectory(), name + ".jpg");
takePhoto.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(destination));
startActivityForResult(intent, REQUEST_IMAGE);
}
});
btnCreate.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
dialog = ProgressDialog.show(SendingImage.this, "", "Uploading file...", true);
new Thread(new Runnable() {
public void run() {
uploadFile(imagePath);
}
}).start();
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if( requestCode == REQUEST_IMAGE && resultCode == Activity.RESULT_OK ){
try {
preview.setVisibility(View.VISIBLE);
takePhoto.setVisibility(View.GONE);
txtHaut.setVisibility(View.VISIBLE);
txtHaut.setText("Immagine selezionata correttamente!");
FileInputStream in = new FileInputStream(destination);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 15;
imagePath = destination.getAbsolutePath();
Log.d("INFO", "PATH === " +imagePath);
//tvPath.setText(imagePath);
Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
preview.setImageBitmap(bmp);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
else{
tvPath.setText("Request cancelled");
}
}
/**
* open camera method
*/
public void callCamera() {
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
cameraIntent.putExtra("crop", "true");
cameraIntent.putExtra("aspectX", 0);
cameraIntent.putExtra("aspectY", 0);
cameraIntent.putExtra("outputX", 200);
cameraIntent.putExtra("outputY", 150);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
/**
* open gallery method
*/
public void callGallery() {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
intent.putExtra("crop", "true");
intent.putExtra("aspectX", 0);
intent.putExtra("aspectY", 0);
intent.putExtra("outputX", 200);
intent.putExtra("outputY", 150);
intent.putExtra("return-data", true);
startActivityForResult(
Intent.createChooser(intent, "Complete action using"),
PICK_FROM_GALLERY);
}
public String dateToString(Date date, String format) {
SimpleDateFormat df = new SimpleDateFormat(format);
return df.format(date);
}
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);
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() {
Toast.makeText(SendingImage.this, "File Upload Complete.", Toast.LENGTH_SHORT).show();
}
});
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();
} catch (MalformedURLException ex) {
dialog.dismiss();
ex.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(SendingImage.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() {
Toast.makeText(SendingImage.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
}
}
这也是php代码：
<?php
$file_path = "uploads/";
$file_path = $file_path . basename( $_FILES['uploaded_file']['name']);
if(move_uploaded_file($_FILES['uploaded_file']['tmp_name'], $file_path)) {
echo "success";
} else{
echo "fail";
}
?>
我以这个项目为例：http://androidexample.com/Upload_File_To_Server_-_Android_Example/index.php?view=article_discription&aid=83&aaid=106
非常感谢您的帮助或建议！
看起来就像是在为上传本身启动一个新线程，这很好。但是这个比特
Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
正在主线程上执行。你应该考虑把它移到背景中，这样你就不会在主线程上读取图像。这可能是你的问题。
更普遍地说，考虑使用AsyncTask来做这些事情：它比创建和管理自己的线程更灵活，也更不容易出错。
它还有一些东西可以让你在后台工作完成后在主线程上做一些事情。因此，使用Bitmap，您可以在doInBackground()方法中进行加载和decodeStream()调用，这发生在后台线程上；然后是下一行
preview.setImageBitmap(bmp);
是您在onPostExecute()中要做的，它（自动）发生在主线程上，因为您必须在主线程中与GUI组件交互。