onPageFinished() 有时不会被调用

Question

我有一个

WebViewClient

的自定义实现，它会覆盖

onPageFinished()

，其中我将加载视图与

WebView

交换。有时一切都很好，但有时

onPageFinished()

根本没有被调用。这是完全随机的。

onPageStarted()

总是接到电话。

public class LoaderWebViewClient extends WebViewClient {

    private final TableLayout swapTableLayout;

    public LoaderWebViewClient(TableLayout swapTableLayout) {
        this.swapTableLayout = swapTableLayout;
    }

    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
        super.onPageStarted(view, url, favicon); 
    }

    // Sometimes doesn't get called
    @Override
    public void onPageFinished(WebView view, String url) {

        swapTableLayout.removeAllViews();
        swapTableLayout.addView(view);

        super.onPageFinished(view, url);
    }
}

我正在从自定义类实例化

WebView

：

WebView webView = new WebView(context);

WebViewClient webViewClient = new LoaderWebViewClient(swapTableLayout);
webView.setWebViewClient(webViewClient);

webView.getSettings().setLoadWithOverviewMode(true);
webView.getSettings().setUseWideViewPort(true);

webView.setVerticalScrollBarEnabled(false);
webView.setHorizontalScrollBarEnabled(false);
webView.getSettings().setJavaScriptEnabled(true);
webView.setOverScrollMode(WebView.OVER_SCROLL_NEVER);
webView.loadUrl(url);

Answer 1

我发现问题了。在

onPageFinished()

中，我将从布局中删除

WebView

本身所在的所有视图（如下一行所示）。

这会以某种方式破坏

WebView

的加载。我刚刚用隐藏和显示视图替换了删除和重新插入视图（它们总是在布局中膨胀），一切似乎都工作正常。

Answer 2

这是 Composable 中带有加载器的完整代码。在此解决方案中，我们还需要一个

if logic

，以免不必要地触发方法

onPageFinished

@Composable
fun WebViewContent(link: String) {
    var isLoading by remember { mutableStateOf(true) }
    var onPageStartedCalled by remember { mutableStateOf(false) }

    val scope = rememberCoroutineScope()
    val context = LocalContext.current

    Box(
        modifier = Modifier
            .fillMaxSize(),
        contentAlignment = Alignment.Center
    ) {
        AndroidView(
            factory = {
                WebView(context).apply {
                    layoutParams = ViewGroup.LayoutParams(
                        ViewGroup.LayoutParams.MATCH_PARENT,
                        ViewGroup.LayoutParams.MATCH_PARENT
                    )

                    var wasCommitCalled = false

                    webViewClient = object : WebViewClient() {
                        override fun shouldOverrideUrlLoading(
                            view: WebView?,
                            url: String?
                        ): Boolean {
                            return if (view != null && url != null) {
                                checkShouldOverrideUrlLoading(view, url)
                            } else false
                        }

                        override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
                            super.onPageStarted(view, url, favicon)
                            wasCommitCalled = false
                            onPageStartedCalled = true
                            isLoading = true
                        }

                        override fun onPageFinished(view: WebView?, url: String?) {
                            if (onPageStartedCalled) {
                                scope.launch {
                                    delay(1500)
                                    if (!wasCommitCalled) {
                                        if (url != null) {
                                            loadUrl(url)
                                        }
                                    }
                                    isLoading = false
                                }
                            }
                        }

                        override fun onPageCommitVisible(view: WebView?, url: String?) {
                            super.onPageCommitVisible(view, url)
                            wasCommitCalled = true
                        }
                    }

                    settings.setSupportZoom(true)
                    settings.builtInZoomControls = true
                    settings.displayZoomControls = false
                    settings.javaScriptEnabled = true
                    settings.useWideViewPort = true

                    loadUrl("https://drive.google.com/viewerng/viewer?embedded=true&url=$link")

                    this.setInitialScale(1)
                }
            },
            modifier = Modifier
                .fillMaxSize()
                .then(Modifier.visibility(!isLoading))
        )

        LoaderContent(
            isLoading = isLoading
        )
    }
}

@Composable
fun Modifier.visibility(isVisible: Boolean): Modifier {
    return if (isVisible) this else alpha(0f)
}

fun checkShouldOverrideUrlLoading(webView: WebView, url: String): Boolean {
    webView.loadUrl(url)
    if (url.endsWith(".pdf") || url.endsWith(".xlsx") || url.endsWith(".xls") || url.endsWith(".doc") || url.endsWith(
            ".docx"
        ) || url.endsWith(".ppt") || url.endsWith(".pptx")
    ) {
        webView.loadUrl("https://docs.google.com/gview?embedded=true&url=$url")
        return true
    }
    return false
}