問題描述

我想在我的應用程序中添加一個圖片上傳器，我可以從圖片文件夾中選擇一張圖片，但是當我選擇一張圖片時，圖片路徑只顯示為null"，當我點擊上傳時，我得到這個錯誤:

I want to add an image uploader to my app, I can choose an image from the image folder, but when I chose an image, the image path is only displayed as "null", and when I click upload, I get this Error:

BitmapFactory:無法解碼流:java.lang.NullPointerException:

這是我的代碼:

package com.test.mysqltest;

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 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 UploadToServer 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.activity_upload_to_server);

    uploadButton = (Button)findViewById(R.id.uploadButton);
    btnselectpic = (Button)findViewById(R.id.button_selectpic);
    messageText  = (TextView)findViewById(R.id.messageText);
    imageview = (ImageView)findViewById(R.id.imageView_pic);

    btnselectpic.setOnClickListener(this);
    uploadButton.setOnClickListener(this);
    upLoadServerUri = "http://www.eywow.com/webservice/UploadToServer.php";
    ImageView img= new ImageView(this);

}


@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(UploadToServer.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);

    }
}
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 = "
";
    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.

 See uploaded file here : 

"
                                +" F:/wamp/wamp/www/uploads";
                        messageText.setText(msg);
                        Toast.makeText(UploadToServer.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() {
                    messageText.setText("MalformedURLException Exception : check script url.");
                    Toast.makeText(UploadToServer.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(UploadToServer.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
}


}

有什么辦法解決這個問題嗎?

推薦答案

在onActivityResult()中直接使用這行代碼

Use this line of code directly in onActivityResult()

Bitmap bitmap=BitmapFactory.decodeStream(getContentResolver().openInputStream(targetUri));

這應該可行.

試著找到自己，兄弟我已經在上面寫過:

Try to find yourself bro I already had written above:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == 1 && resultCode == RESULT_OK) {
            ...
            Bitmap bitmap=BitmapFactory.decodeStream(getContentResolver().openInputStream(targetUri));
            imageview.setImageBitmap(bitmap);
            ...
        }
    }

這篇關于BitmapFactory:無法解碼流 - null的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！