运行时异常无法在未调用looper.prepare错误的线程内创建处理程序
郁鸿博
问题内容：
问题答案：
我正在尝试使用其他EditText上传照片。我从一个在线示例中获取了示例代码，并对其进行了少量编辑，但我收到此错误：
08-29 21:36:46.000: E/AndroidRuntime(4566): FATAL EXCEPTION: AsyncTask #1
08-29 21:36:46.000: E/AndroidRuntime(4566): java.lang.RuntimeException: An error occured while executing doInBackground()
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.os.AsyncTask$3.done(AsyncTask.java:299)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.lang.Thread.run(Thread.java:856)
08-29 21:36:46.000: E/AndroidRuntime(4566): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.os.Handler.<init>(Handler.java:121)
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.widget.Toast$TN.<init>(Toast.java:361)
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.widget.Toast.<init>(Toast.java:97)
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.widget.Toast.makeText(Toast.java:254)
08-29 21:36:46.000: E/AndroidRuntime(4566): at com.example.imageupload.ImageUpload$ImageUploadTask.doInBackground(ImageUpload.java:177)
08-29 21:36:46.000: E/AndroidRuntime(4566): at com.example.imageupload.ImageUpload$ImageUploadTask.doInBackground(ImageUpload.java:1)
08-29 21:36:46.000: E/AndroidRuntime(4566): at android.os.AsyncTask$2.call(AsyncTask.java:287)
08-29 21:36:46.000: E/AndroidRuntime(4566): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-29 21:36:46.000: E/AndroidRuntime(4566): ... 5 more
我的Android代码：
package com.example.imageupload;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.ByteArrayBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
public class ImageUpload extends Activity {
private static final int PICK_IMAGE = 1;
private ImageView imgView;
private Button upload;
private EditText TraineeID, ExamID, Invoiceno;
private Bitmap bitmap;
private ProgressDialog dialog;
private String url = "www.orgaar.com/androidlogin/imageupload.php";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.uploadimage);
imgView = (ImageView) findViewById(R.id.ImageView);
upload = (Button) findViewById(R.id.Upload);
Invoiceno = (EditText) findViewById(R.id.Invoiceno);
TraineeID = (EditText) findViewById(R.id.TraineeID);
ExamID = (EditText) findViewById(R.id.ExamID);
upload.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (bitmap == null) {
Toast.makeText(getApplicationContext(),
"Please select image", Toast.LENGTH_SHORT).show();
} else {
dialog = ProgressDialog.show(ImageUpload.this, "Uploading",
"Please wait...", true);
new ImageUploadTask().execute();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.imageupload_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.ic_menu_gallery:
try {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(
Intent.createChooser(intent, "Select Picture"),
PICK_IMAGE);
} catch (Exception e) {
Toast.makeText(getApplicationContext(),
e.getMessage(),
Toast.LENGTH_LONG).show();
Log.e(e.getClass().getName(), e.getMessage(), e);
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case PICK_IMAGE:
if (resultCode == Activity.RESULT_OK) {
Uri selectedImageUri = data.getData();
String filePath = null;
try {
// OI FILE Manager
String filemanagerstring = selectedImageUri.getPath();
// MEDIA GALLERY
String selectedImagePath = getPath(selectedImageUri);
if (selectedImagePath != null) {
filePath = selectedImagePath;
} else if (filemanagerstring != null) {
filePath = filemanagerstring;
} else {
Toast.makeText(getApplicationContext(), "Unknown path",
Toast.LENGTH_LONG).show();
Log.e("Bitmap", "Unknown path");
}
if (filePath != null) {
decodeFile(filePath);
} else {
bitmap = null;
}
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "Internal error",
Toast.LENGTH_LONG).show();
Log.e(e.getClass().getName(), e.getMessage(), e);
}
}
break;
default:
}
}
class ImageUploadTask extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... unsued) {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url);
MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.JPEG, 100, bos);
byte[] data = bos.toByteArray();
entity.addPart("returnformat", new StringBody("json"));
entity.addPart("uploaded", new ByteArrayBody(data,"myImage.jpg"));
entity.addPart("Invoiceno", new StringBody(Invoiceno.getText().toString()));
entity.addPart("TraineeID", new StringBody(TraineeID.getText().toString()));
entity.addPart("ExamID", new StringBody(ExamID.getText().toString()));
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost,
localContext);
BufferedReader reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
String sResponse = reader.readLine();
return sResponse;
} catch (Exception e) {
if (dialog.isShowing())
dialog.dismiss();
Toast.makeText(getApplicationContext(),
e.getMessage(),
Toast.LENGTH_LONG).show();
Log.e(e.getClass().getName(), e.getMessage(), e);
return null;
}
// (null);
}
@Override
protected void onProgressUpdate(Void... unsued) {
}
@Override
protected void onPostExecute(String sResponse) {
try {
if (dialog.isShowing())
dialog.dismiss();
if (sResponse != null) {
JSONObject JResponse = new JSONObject(sResponse);
int success = JResponse.getInt("SUCCESS");
String message = JResponse.getString("MESSAGE");
if (success == 0) {
Toast.makeText(getApplicationContext(), message,
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(),
"Photo uploaded successfully",
Toast.LENGTH_SHORT).show();
Invoiceno.setText("");
}
}
} catch (Exception e) {
Toast.makeText(getApplicationContext(),
e.getMessage(),
Toast.LENGTH_LONG).show();
Log.e(e.getClass().getName(), e.getMessage(), e);
}
}
}
public String getPath(Uri uri) {
String[] projection = { MediaStore.Images.Media.DATA };
Cursor cursor = managedQuery(uri, projection, null, null, null);
if (cursor != null) {
// HERE YOU WILL GET A NULLPOINTER IF CURSOR IS NULL
// THIS CAN BE, IF YOU USED OI FILE MANAGER FOR PICKING THE MEDIA
int column_index = cursor
.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
} else
return null;
}
public void decodeFile(String filePath) {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, o);
// The new size we want to scale to
final int REQUIRED_SIZE = 1024;
// Find the correct scale value. It should be the power of 2.
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp < REQUIRED_SIZE && height_tmp < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
bitmap = BitmapFactory.decodeFile(filePath, o2);
imgView.setImageBitmap(bitmap);
}
}
请告诉我这里是什么问题，我该如何解决呢？预先感谢我知道，常见的答案是我需要从UI线程调用Toast.makeText（…）：很抱歉，因为我很新任何人都介意对此进行更详细的解释
问题答案：
可能由于此行而出现错误
Toast.makeText(getApplicationContext(),
e.getMessage(),
Toast.LENGTH_LONG).show();
里面doInBackground。Toast必须显示在UIThread上。相反，您使用的是doInBackground线程来显示它。通常，有关UI的所有操作都必须在UI线程上执行。如果要修复，可以使用处理程序在显示Toast的UI线程队列上发布可运行对象
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