在 Android webview 中通过 Googler 驱动器显示 pdf 时显示空白页

Question

I show my pdfs via https://docs.google.com/viewer?embedded=true&url= {my pdf link} in WebView. Sometimes my WebView shows a blank page without any error in "onReceivedError" method. Why this blank page show?

Answer 1

Take this as an example.

class PdfViewActivity : AppCompatActivity() {
    private lateinit var activityPdfViewBinding: ActivityPdfViewBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        activityPdfViewBinding = DataBindingUtil.setContentView(this, R.layout.activity_pdf_view)
        val path =  "https://github.github.com/training-kit/downloads/github-git-cheat-sheet.pdf" // Add Your URL here
        loadPdfFromURL(path)
    }

    @SuppressLint("SetJavaScriptEnabled")
    private fun loadPdfFromURL(path: String?) {
        activityPdfViewBinding.webview.settings.loadWithOverviewMode = true
        activityPdfViewBinding.webview.settings.javaScriptEnabled = true
        val url = "https://docs.google.com/gview?embedded=true&url=$path"
        activityPdfViewBinding.webview.loadUrl(url)
    }
}

also, add these lines into onPageFinished method

if (view.getTitle().equals("")) { 
   view.reload();
}

Answer 2

To resolve blank gview issue. You can do it by using HTML & JQuery.

HTML Code:
<iframe  id="assetDivIdMob" src="https://docs.google.com/gview?embedded=true&amp;url=YOUR-PDF-URL.pdf" width="100%" height="100%" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe> 


JQuery code:

//Wait for some time & then call loadPDF
setTimeout(function(){ 
    loadPDF(); 
},1050);

function loadPDF() {
    //This statement will raise DOMException if gview PDF already loaded in Iframe & Code excution will stop.
    document.getElementById('assetDivIdMob').contentWindow.document;

    //If iframe is blank then reload Iframe.
    $('#assetDivIdMob').attr('src', $('#assetDivIdMob').attr('src'));

    console.log("reloading iframe...");  

    //Call loadPDF() after sometime & load PDF in Iframe till it is loaded in Iframe.
    setTimeout(loadPDF, 2000);
 }