错误-从 android Webview 中的 URL 加载 PDF

Question

我正在尝试从 Web 视图中的 URL 加载 PDF 文件，而不在 android 中下载。大多数时候它的加载很完美，但有时会出现下面提到的错误。

错误：1

 ERROR:gles2_cmd_decoder.cc(2787)] [GroupMarkerNotSet(crbug.com/242999)!:B0F7473971000000] GL ERROR :GL_INVALID_FRAMEBUFFER_OPERATION : BackFramebuffer::Create: <- error from previous GL command

错误：2

validate_display:99 error 3008 (EGL_BAD_DISPLAY)

代码片段：

init() 方法在 On-create 内部调用

private void init()
{
    WebView webview = (WebView) findViewById(R.id.webview);
    WebSettings settings = webview.getSettings();
    settings.setJavaScriptEnabled(true);
    webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);

    PdfWebViewClient pdfWebViewClient = new PdfWebViewClient(this, webview);
    pdfWebViewClient.loadPdfUrl(
                "YOUR URL for Loading PDF");
}

PdfWebViewClient.java

private class PdfWebViewClient extends WebViewClient
{
    private static final String TAG = "PdfWebViewClient";
    private static final String PDF_EXTENSION = ".pdf";
    private static final String PDF_VIEWER_URL = "http://docs.google.com/gview?embedded=true&url=";

    private Context mContext;
    private WebView mWebView;
    private ProgressDialog mProgressDialog;
    private boolean isLoadingPdfUrl;

    public PdfWebViewClient(Context context, WebView webView)
    {
        mContext = context;
        mWebView = webView;
        mWebView.setWebViewClient(this);
    }

    public void loadPdfUrl(String url)
    {
        mWebView.stopLoading();

        if (!TextUtils.isEmpty(url))
        {
            isLoadingPdfUrl = isPdfUrl(url);
            if (isLoadingPdfUrl)
            {
                mWebView.clearHistory();
            }

            showProgressDialog();
        }

        mWebView.loadUrl(url);
    }

    @SuppressWarnings("deprecation")
    @Override
    public boolean shouldOverrideUrlLoading(WebView webView, String url)
    {
        return shouldOverrideUrlLoading(url);
    }

    @SuppressWarnings("deprecation")
    @Override
    public void onReceivedError(WebView webView, int errorCode, String description, String failingUrl)
    {
        handleError(errorCode, description.toString(), failingUrl);
    }

    @TargetApi(Build.VERSION_CODES.N)
    @Override
    public boolean shouldOverrideUrlLoading(WebView webView, WebResourceRequest request)
    {
        final Uri uri = request.getUrl();
        return shouldOverrideUrlLoading(webView, uri.toString());
    }

    @TargetApi(Build.VERSION_CODES.N)
    @Override
    public void onReceivedError(final WebView webView, final WebResourceRequest request, final WebResourceError error)
    {
        final Uri uri = request.getUrl();
        handleError(error.getErrorCode(), error.getDescription().toString(), uri.toString());
    }

    @Override
    public void onPageFinished(final WebView view, final String url)
    {
        Log.i(TAG, "Finished loading. URL : " + url);
        dismissProgressDialog();
    }

    private boolean shouldOverrideUrlLoading(final String url)
    {
        Log.i(TAG, "shouldOverrideUrlLoading() URL : " + url);

        if (!isLoadingPdfUrl && isPdfUrl(url))
        {
            mWebView.stopLoading();

            final String pdfUrl = PDF_VIEWER_URL + url;

            new Handler().postDelayed(new Runnable()
            {
                @Override
                public void run()
                {
                    loadPdfUrl(pdfUrl);
                }
            }, 300);

            return true;
        }

        return false; // Load url in the webView itself
    }

    private void handleError(final int errorCode, final String description, final String failingUrl)
    {
        Log.e(TAG, "Error : " + errorCode + ", " + description + " URL : " + failingUrl);
    }

    private void showProgressDialog()
    {
        dismissProgressDialog();
        mProgressDialog = ProgressDialog.show(mContext, "", "Loading...");
    }

    private void dismissProgressDialog()
    {
        if (mProgressDialog != null && mProgressDialog.isShowing())
        {
            mProgressDialog.dismiss();
            mProgressDialog = null;
        }
    }

    private boolean isPdfUrl(String url)
    {
        if (!TextUtils.isEmpty(url))
        {
            url = url.trim();
            int lastIndex = url.toLowerCase().lastIndexOf(PDF_EXTENSION);
            if (lastIndex != -1)
            {
                return url.substring(lastIndex).equalsIgnoreCase(PDF_EXTENSION);
            }
        }
        return false;
    }
}

Answer 1

有时缓冲区问题与缓存溢出有关。尝试将webview.clearCache(true) 添加到您的代码中。

更新：

private void init()
{
    WebView webview = (WebView) findViewById(R.id.webview);
    WebSettings settings = webview.getSettings();
    settings.setJavaScriptEnabled(true);
    webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
    webview.clearCache(true); // add this string

    PdfWebViewClient pdfWebViewClient = new PdfWebViewClient(this, webview);
    pdfWebViewClient.loadPdfUrl(
            "YOUR URL for Loading PDF");

}

Answer 2

您实际上可以使用this great library 在您的应用中通过 URL 查看 PDF。