java.lang.NoClassDefFoundError : Failed resolution of: Landroid/webkit/PacProcessor

Question

真的找不到词，我的项目只是不从一天编译到另一天。
这就是我所做的:
我下载并显示一个 PDF，然后我将其作为保存的 PDF 打印到设备上，然后崩溃发生了。
这是崩溃:

at java.lang.Class java.lang.Class.classForName(java.lang.String, boolean, java.lang.ClassLoader) (Class.java:-2)
   at java.lang.Class java.lang.Class.forName(java.lang.String, boolean, java.lang.ClassLoader) (Class.java:453)
   at java.lang.Class android.webkit.WebViewFactory.getWebViewProviderClass(java.lang.ClassLoader) (WebViewFactory.java:176)
   at java.lang.Class android.webkit.WebViewFactory.getProviderClass() (WebViewFactory.java:459)
   at android.webkit.WebViewFactoryProvider android.webkit.WebViewFactory.getProvider() (WebViewFactory.java:251)
   at android.webkit.WebViewFactoryProvider android.webkit.WebView.getFactory() (WebView.java:2681)
   at void android.webkit.WebView.ensureProviderCreated() (WebView.java:2676)
   at void android.webkit.WebView.setOverScrollMode(int) (WebView.java:2741)
   at void android.view.View.<init>(android.content.Context) (View.java:4815)
   at void android.view.View.<init>(android.content.Context, android.util.AttributeSet, int, int) (View.java:4956)
   at void android.view.ViewGroup.<init>(android.content.Context, android.util.AttributeSet, int, int) (ViewGroup.java:659)
   at void android.widget.AbsoluteLayout.<init>(android.content.Context, android.util.AttributeSet, int, int) (AbsoluteLayout.java:55)
   at void android.webkit.WebView.<init>(android.content.Context, android.util.AttributeSet, int, int, java.util.Map, boolean) (WebView.java:659)
   at void android.webkit.WebView.<init>(android.content.Context, android.util.AttributeSet, int, int) (WebView.java:604)
   at void android.webkit.WebView.<init>(android.content.Context, android.util.AttributeSet, int) (WebView.java:587)
   at void android.webkit.WebView.<init>(android.content.Context, android.util.AttributeSet) (WebView.java:574)
   at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
   at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:343)
   at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
   at android.view.View com.android.internal.policy.PhoneLayoutInflater.onCreateView(java.lang.String, android.util.AttributeSet) (PhoneLayoutInflater.java:58)
   at android.view.View android.view.LayoutInflater.onCreateView(android.view.View, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:720)
   at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:788)

(实际的错误太长了，我无法在stackoverflow中发布，而且都不是我自己的代码，它与Android的webview有问题。)

这是发生崩溃的 Activity 代码:

public class ActivityPrintSurvey extends ActivityBase implements MVPView, View.OnClickListener, SendScannedSignedDocumentTask.SendScannedSignedDocumentCallback {
    
    Document document;
    Patient patient;
    SurveyBundle surveyBundle;

    View hider;
    Button printBtn;
    Button backBtn;
    WebView webView;
    ProgressBar progressBar;
    Switch switcher;

    boolean canPrint = false;

    PrintManager printManager;
    String jobName;

    String fileName;

    String pdfUrl;
    String showPdfUrl;
    private int SIGNING_DONE_1 = 105;

    int runnableCounter = 0;
    final int RUNNABLE_MAX = 3;

    private void log(Object o) {

        Log.i("PRINTING_ACT", o.toString());
    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_print_survey);


        log("activity started");

        hider = findViewById(R.id.hider);
        printBtn = findViewById(R.id.print_btn);
        backBtn = findViewById(R.id.back_btn);
        webView = findViewById(R.id.web_view);
        progressBar = findViewById(R.id.progressbar);
        switcher = findViewById(R.id.read_and_accepted_switch);


        document = (Document) getIntent().getSerializableExtra("document");
        patient = (Patient) getIntent().getSerializableExtra("patient");
        surveyBundle = (SurveyBundle) getIntent().getSerializableExtra("survey_bundle");

        jobName = this.getString(R.string.app_name) + " Document";
        printManager = (PrintManager) this.getSystemService(Context.PRINT_SERVICE);

        printBtn.setOnClickListener(this);
        backBtn.setOnClickListener(this);


        showPDF();
    }


    private void showPDF() {

        log("starting to show pdf");

        pdfUrl = document.getPdfUrl();

        String embedUrl = "https://docs.google.com/gview?embedded=true&url=";
        showPdfUrl = embedUrl + pdfUrl;

        progressBar.setVisibility(View.VISIBLE);
        hider.setVisibility(View.VISIBLE);

        final Handler handler = new Handler();
        Runnable runnable = new Runnable() {
            @Override
            public void run() {

                if (runnableCounter < RUNNABLE_MAX) {
                    runnableCounter++;
                    webView.getSettings().setJavaScriptEnabled(true);
                    webView.loadUrl(showPdfUrl);
                    handler.postDelayed(this, 1000);
                    //Szörnyűséges a helyzet, az android szemét használhatatlan webview nem mindig jeleníti meg a pdf-et, ezért rá kell frissíteni párszor, hogy biztos megjelenítse, ez van.
                } else {
                    progressBar.setVisibility(View.GONE);
                    hider.setVisibility(View.GONE);

                }
            }
        };
        handler.post(runnable);
        downloadPDF();
    }


    public void downloadPDF() {

        log("starting to download pdf");

        fileName = FileHelper.generateTempFileName();

        ANRequest.DownloadBuilder downloadBuilder = AndroidNetworking.download(pdfUrl, FileHelper.getTempFileDirectory(this), fileName);
        downloadBuilder.doNotCacheResponse();
        ANRequest request = downloadBuilder.build();

        request.setDownloadProgressListener(new DownloadProgressListener() {
            @Override
            public void onProgress(long bytesDownloaded, long totalBytes) {
                // do anything with progress
                Log.i("ON_PROGRESS", bytesDownloaded + " / " + totalBytes);

            }
        }).startDownload(new DownloadListener() {
            @Override
            public void onDownloadComplete() {
                // do anything after completion
                canPrint = true;
            }

            @Override
            public void onError(ANError error) {
                // handle error
                Toast.makeText(ActivityPrintSurvey.this, error.getMessage(), Toast.LENGTH_LONG).show();
            }
        });

    }

    public void print() {

        log("starting to print");

        printManager.print(jobName, new PrintDocumentAdapter() {


            @Override
            public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback) {
                InputStream input = null;
                OutputStream output = null;

                log("onWrite() called for printing");

                try {

                    File file = FileHelper.readTempFile(ActivityPrintSurvey.this, fileName);

                    input = new FileInputStream(file);
                    output = new FileOutputStream(destination.getFileDescriptor());

                    byte[] buf = new byte[1024];
                    int bytesRead;

                    while ((bytesRead = input.read(buf)) > 0) {
                        output.write(buf, 0, bytesRead);
                    }

                    callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});
                    log("onWriteFinished() called for printing");

                } catch (Exception e) {
                    //Catch exception
                    e.printStackTrace();
                    log("Exception 1: " + e.getMessage());
                } finally {
                    try {
                        input.close();
                        output.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                        log("Exception 2: " + e.getMessage());
                    }
                }
            }

            @Override
            public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras) {
                log("onLayout() done");

                if (cancellationSignal.isCanceled()) {
                    callback.onLayoutCancelled();
                    log("onLayoutCancelled()");
                    return;
                }

                PrintDocumentInfo pdi = new PrintDocumentInfo.Builder(fileName/*Ez itt lehet bármi, kiskutya füle, nem kell megegyeznie az alap file nevvel*/).setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();
                callback.onLayoutFinished(pdi, true);
                log("onLayoutFinished() called");
            }

            @Override
            public void onFinish() {

                FileHelper.deleteTempFiles(ActivityPrintSurvey.this);

                log("onFinish() done");

                // ha kész a nyomtatás, jöhet a valós aláírás tollal, majd visszafotózás, és feltöltés

                new AlertDialog.Builder(ActivityPrintSurvey.this)
                        .setTitle(getString(R.string.next_step))
                        .setMessage(getString(R.string.please_scan_the_printed_and_signed_document))
                        .setPositiveButton(getString(R.string.scan), new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                startScanningByCameraPhoto();
                            }
                        })
                        .setNegativeButton(getString(R.string.cancel), new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {

                            }
                        })
                        .show();

                log("showing alert dialog");

            }
        }, null);
    }

    public void startScanningByCameraPhoto() {

        // start picker to get image for cropping and then use the image in cropping activity
        CropImage.activity()
                .setGuidelines(CropImageView.Guidelines.ON)
                .start(this);

        log("startScanningByCameraPhoto");
    }

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

        log("onActivityResult called");

        if (resultCode == Activity.RESULT_OK) {
            if (requestCode == SIGNING_DONE_1) {

                log("RESULT_OK from SIGNING_DONE_1 -> calling .finish()");

                Intent intent = new Intent();
                intent.putExtra("document", document);
                setResult(Activity.RESULT_OK, intent);
                finish();
            }
        } else {
            log("1. Error: resultCode NOT RESULT OK");
        }

        if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) {
            CropImage.ActivityResult result = CropImage.getActivityResult(data);
            if (resultCode == RESULT_OK) {

                log("RESULT_OK from CROP_IMAGE_ACTIVITY_REQUEST_CODE");

                Uri resultUri = result.getUri();

                File file = new File(resultUri.getPath());

                showLoading();

                SendScannedSignedDocumentTask task = new SendScannedSignedDocumentTask(this, this, DatabaseHelper.getInstance().readLoggedInUser().getUserToken(), document, patient, file);
                task.execute();

            } else if (resultCode == CropImage.CROP_IMAGE_ACTIVITY_RESULT_ERROR_CODE) {
                Exception error = result.getError();
                log("2. Error: resultCode NOT RESULT OK: " + error.getMessage());
                error.printStackTrace();
            }
        }

    }


    @Override
    public void handleUploadScannedDocumentAPIDone(String error) {

        hideLoading();

        if (error != null) {
            log("handleUploadScannedDocumentAPIDone, error:" + error);
            DialogHelper.showInfo(this, error);
        } else {
            log("handleUploadScannedDocumentAPIDone -> finishing()");
            setResult(Activity.RESULT_OK);
            Toast.makeText(this, "✔ " + getString(R.string.uploaded), Toast.LENGTH_LONG).show();
            finish();
        }
    }

    @Override
    public void onClick(View v) {

        if (v.equals(printBtn)) {

            if (switcher.isChecked()) {
                if (canPrint) {
                    print();
                } else {
                    Toast.makeText(this, "PDF not found in device. Retrying download...", Toast.LENGTH_LONG).show();
                    downloadPDF();
                }
            } else {
                DialogHelper.showInfo(this, getString(R.string.please_check_the_checkbox));
            }

        } else if (v.equals(backBtn)) {
            onBackPressed();
        }
    }

    public void hideLoading() {
        progressBar.setVisibility(View.GONE);
    }

    @Override
    public void showLoading() {
        progressBar.setVisibility(View.VISIBLE);
    }

    @Override
    public void showError(String error, String code) {
        hideLoading();
        canPrint = false;
        DialogHelper.showError(this, error);
        log("showing error: " + error);
    }


    @Override
    public void showSuccess(Object... object) {

        hideLoading();

        String api = object[0].toString();

        if (api.equals("eject_patient")) {

            log("showSuccess: " + "finishing activity.");

            Intent intent = new Intent(this, ActivityWaitingForPatient.class);
            startActivity(intent);
            finish();

        } else {
            log("showSuccess: " + "ERROR: " + api + " not equals " + "eject_patient");
        }
    }


    @Override
    public void onResume() {
        super.onResume();
        LayoutTextSizeChanger.changeAllTextSizeInLayout((ViewGroup) findViewById(R.id.main_cont), FontUtil.loadFontSize(this));

        log("onResume()"  );
    }


}

Answer 1

嗯...引用类加载器问题的间歇性问题。 + 一个巨大的堆栈跟踪。
您提供的少量证据可能指向无声的 IO 类型错误。
例如，您正在使用的 android 在运行时动态加载类，并且由于某种原因，它尝试使用的任何 jar 的主机文件夹还包含该 pdf 文件，该文件主动写入/读取...或出于任何原因，整个文件系统分区被标记为锁定。
在这种情况下，您会遇到间歇性的类加载器错误，就像您引用的错误一样。
还有这个:

try {
    input.close(); <--- if exception occurs at this point, output will never close.
    output.close();
} catch (IOException e) {
    e.printStackTrace();
    log("Exception 2: " + e.getMessage());
}

......我不知道......老实说，几乎没有什么信息可以引用。例如，您没有发布 finish() 的内容例程，并且该堆栈跟踪不包含对您的代码的引用(至少我可以看到)......所以这是一种在黑暗中的狂野刺伤。