我有一个 HTML 网页，其中有一个按钮，当用户单击时会触发 POST 请求。请求完成后，将触发以下代码：
window.open(fileUrl);
在浏览器中一切正常，但是在 Webview 组件中实现时，新选项卡不会打开。
仅供参考：在我的 Android 应用程序上，我设置了以下内容：
webview.getSettings().setJavaScriptEnabled(true);
webview.getSettings().setSupportMultipleWindows(true);
webview.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
在
AndroidManifest.xml<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_DOWNLOAD_MANAGER"/>
我也尝试使用
setDownloadListenerWebViewClient()WebChromeClient()好吧，我在使用 webviews 时遇到了同样的问题，我意识到 WebViewClient 无法像 Chrome 桌面客户端那样加载“blob URL”。我使用 Javascript 接口解决了它。您可以按照以下步骤执行此操作，并且它可以与 minSdkVersion 一起正常工作： 17. 首先，使用 JS 将 Blob URL 数据转换为 Base64 字符串。其次，将此字符串发送到 Java 类，最后将其转换为可用格式，在这种情况下，我将其转换为“.pdf”文件。
在继续之前，您可以在这里下载源代码:)。该应用程序是用 Kotlin 和 Java 开发的。如果您发现任何错误，请告诉我，我会修复它：
https://github.com/JaegerCodes/AmazingAndroidWebview
要事第一。你必须设置你的网络视图。在我的例子中，我在片段中加载网页：
public class WebviewFragment extends Fragment {
WebView browser;
...
// invoke this method after set your WebViewClient and ChromeClient
private void browserSettings() {
browser.getSettings().setJavaScriptEnabled(true);
browser.setDownloadListener(new DownloadListener() {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimeType, long contentLength) {
browser.loadUrl(JavaScriptInterface.getBase64StringFromBlobUrl(url));
}
});
browser.getSettings().setAppCachePath(getActivity().getApplicationContext().getCacheDir().getAbsolutePath());
browser.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
browser.getSettings().setDatabaseEnabled(true);
browser.getSettings().setDomStorageEnabled(true);
browser.getSettings().setUseWideViewPort(true);
browser.getSettings().setLoadWithOverviewMode(true);
browser.addJavascriptInterface(new JavaScriptInterface(getContext()), "Android");
browser.getSettings().setPluginState(PluginState.ON);
}
}
最后，创建一个JavaScriptInterface类。此类包含将在我们的网页中执行的脚本。
public class JavaScriptInterface {
private Context context;
public JavaScriptInterface(Context context) {
this.context = context;
}
@JavascriptInterface
public void getBase64FromBlobData(String base64Data) throws IOException {
convertBase64StringToPdfAndStoreIt(base64Data);
}
public static String getBase64StringFromBlobUrl(String blobUrl) {
if(blobUrl.startsWith("blob")){
return "javascript: var xhr = new XMLHttpRequest();" +
"xhr.open('GET', '"+ blobUrl +"', true);" +
"xhr.setRequestHeader('Content-type','application/pdf');" +
"xhr.responseType = 'blob';" +
"xhr.onload = function(e) {" +
" if (this.status == 200) {" +
" var blobPdf = this.response;" +
" var reader = new FileReader();" +
" reader.readAsDataURL(blobPdf);" +
" reader.onloadend = function() {" +
" base64data = reader.result;" +
" Android.getBase64FromBlobData(base64data);" +
" }" +
" }" +
"};" +
"xhr.send();";
}
return "javascript: console.log('It is not a Blob URL');";
}
private void convertBase64StringToPdfAndStoreIt(String base64PDf) throws IOException {
final int notificationId = 1;
String currentDateTime = DateFormat.getDateTimeInstance().format(new Date());
final File dwldsPath = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOWNLOADS) + "/YourFileName_" + currentDateTime + "_.pdf");
byte[] pdfAsBytes = Base64.decode(base64PDf.replaceFirst("^data:application/pdf;base64,", ""), 0);
FileOutputStream os;
os = new FileOutputStream(dwldsPath, false);
os.write(pdfAsBytes);
os.flush();
if (dwldsPath.exists()) {
Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
Uri apkURI = FileProvider.getUriForFile(context,context.getApplicationContext().getPackageName() + ".provider", dwldsPath);
intent.setDataAndType(apkURI, MimeTypeMap.getSingleton().getMimeTypeFromExtension("pdf"));
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
PendingIntent pendingIntent = PendingIntent.getActivity(context,1, intent, PendingIntent.FLAG_CANCEL_CURRENT);
String CHANNEL_ID = "MYCHANNEL";
final NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
NotificationChannel notificationChannel= new NotificationChannel(CHANNEL_ID,"name", NotificationManager.IMPORTANCE_LOW);
Notification notification = new Notification.Builder(context,CHANNEL_ID)
.setContentText("You have got something new!")
.setContentTitle("File downloaded")
.setContentIntent(pendingIntent)
.setChannelId(CHANNEL_ID)
.setSmallIcon(android.R.drawable.sym_action_chat)
.build();
if (notificationManager != null) {
notificationManager.createNotificationChannel(notificationChannel);
notificationManager.notify(notificationId, notification);
}
} else {
NotificationCompat.Builder b = new NotificationCompat.Builder(context, CHANNEL_ID)
.setDefaults(NotificationCompat.DEFAULT_ALL)
.setWhen(System.currentTimeMillis())
.setSmallIcon(android.R.drawable.sym_action_chat)
//.setContentIntent(pendingIntent)
.setContentTitle("MY TITLE")
.setContentText("MY TEXT CONTENT");
if (notificationManager != null) {
notificationManager.notify(notificationId, b.build());
Handler h = new Handler();
long delayInMilliseconds = 1000;
h.postDelayed(new Runnable() {
public void run() {
notificationManager.cancel(notificationId);
}
}, delayInMilliseconds);
}
}
}
Toast.makeText(context, "PDF FILE DOWNLOADED!", Toast.LENGTH_SHORT).show();
}
}
额外：如果您想与其他应用程序共享这些下载的文件，请创建一个 xml 文件：.. es\xml\provider_paths.xml
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/>
</paths>
最后将此提供程序添加到您的 AndroidManifest.xml 文件中
<application ...>
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>
<!-- some code below ->
另一种方法是使用“Chrome 自定义标签”
爪哇：
CustomTabsIntent.Builder builder = new CustomTabsIntent.Builder();
CustomTabsIntent customTabsIntent = builder.build();
customTabsIntent.launchUrl(context, Uri.parse("https://stackoverflow.com"));
科特林：
val url = "https://stackoverflow.com/"
val builder = CustomTabsIntent.Builder()
val customTabsIntent = builder.build()
customTabsIntent.launchUrl(this, Uri.parse(url))
来源：
https://stackoverflow.com/a/41339946/4001198
https://stackoverflow.com/a/11901662/4001198
https://stackoverflow.com/a/19959041/4001198
https://developer.android.com/training/secure-file-sharing/setup-sharing
我最近遇到了这个问题，发现解决方案是在我的 setDownloadListener 上使用字符串操作 url。
例如：
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url.replace("blob:","").trim()));
我正在使用下载管理器并处理 url 字符串并对其进行修剪，希望这对您有所帮助
我最近在 Android 上遇到了类似的问题。多亏了这个帖子，我才能找到解决方法！
我在 Kotlin 中重用和重构了上面分享的代码片段
解释：WebViewClient 无法加载 Blob URL。解决方法是将 Blob URL 转换为 Blob 对象，然后在 Web 端转换为 Base64 数据。本端会根据Base64数据前缀中指定的mime类型下载Base64数据中的附件
JavascriptInterface.kt
import android.content.Context
import android.os.Environment
import android.util.Base64
import android.util.Log
import android.webkit.JavascriptInterface
import android.widget.Toast
import java.io.File
import java.io.FileOutputStream
class JavascriptInterface {
var context: Context;
constructor(context: Context) {
this.context = context;
}
/**
* Method to process Base64 data then save it locally.
*
* 1. Strip Base64 prefix from Base64 data
* 2. Decode Base64 data
* 3. Write Base64 data to file based on mime type located in prefix
* 4. Save file locally
*/
@JavascriptInterface
fun processBase64Data(base64Data: String) {
Log.i("JavascriptInterface/processBase64Data", "Processing base64Data ...")
var fileName = "";
var bytes = "";
if (base64Data.startsWith("data:image/png;base64,")) {
fileName = "foo.png"
bytes = base64Data.replaceFirst("data:image/png;base64,","")
}
if (fileName.isNotEmpty() && bytes.isNotEmpty()) {
val downloadPath = File(
Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS),
fileName
)
Log.i("JavascriptInterface/processBase64Data", "Download Path: ${downloadPath.absolutePath}")
val decodedString = Base64.decode(bytes, Base64.DEFAULT)
val os = FileOutputStream(downloadPath, false)
os.write(decodedString)
os.flush()
}
}
/**
* Method to convert blobUrl to Blob, then process Base64 data on native side
*
* 1. Download Blob URL as Blob object
* 2. Convert Blob object to Base64 data
* 3. Pass Base64 data to Android layer for processing
*/
fun getBase64StringFromBlobUrl(blobUrl: String): String {
Log.i("JavascriptInterface/getBase64StringFromBlobUrl", "Downloading $blobUrl ...")
// Script to convert blob URL to Base64 data in Web layer, then process it in Android layer
val script = "javascript: (() => {" +
"async function getBase64StringFromBlobUrl() {" +
"const xhr = new XMLHttpRequest();" +
"xhr.open('GET', '${blobUrl}', true);" +
"xhr.setRequestHeader('Content-type', 'image/png');" +
"xhr.responseType = 'blob';" +
"xhr.onload = () => {" +
"if (xhr.status === 200) {" +
"const blobResponse = xhr.response;" +
"const fileReaderInstance = new FileReader();" +
"fileReaderInstance.readAsDataURL(blobResponse);" +
"fileReaderInstance.onloadend = () => {" +
"console.log('Downloaded' + ' ' + '${blobUrl}' + ' ' + 'successfully!');" +
"const base64data = fileReaderInstance.result;" +
"Android.processBase64Data(base64data);" +
"}" + // file reader on load end
"}" + // if
"};" + // xhr on load
"xhr.send();" +
"}" + // async function
"getBase64StringFromBlobUrl();" +
"}) ()"
return script
}
}
MainActivity.kt
import android.Manifest
import android.content.pm.PackageManager
import android.os.Bundle
import android.support.v4.app.ActivityCompat
import android.support.v7.app.AppCompatActivity
import android.webkit.DownloadListener
import android.webkit.WebView
import java.net.URL
class MainActivity : AppCompatActivity() {
var debug = true
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Request permissions
ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE), PackageManager.PERMISSION_GRANTED);
val wv = findViewById<WebView>(R.id.web_view)
wv.settings.javaScriptEnabled = true
wv.settings.domStorageEnabled = true
// Load local .html with baseUrl set to production domain since attachment downloads does not work cross-origin
val queryParams = "foo=bar"
var url = URL(OmnichannelConfig.config["src"])
val baseUrl = "${url.protocol}://${url.host}?${queryParams}"
val data = application.assets.open("index.html").bufferedReader().use {
it.readText()
};
wv.loadDataWithBaseURL(baseUrl, data, "text/html", null, baseUrl)
// Expose Android methods to Javascript layer
val javascriptInterface = JavascriptInterface(applicationContext)
wv.addJavascriptInterface(javascriptInterface, "Android")
// Subscribe to notification when a file from Web content needs to be downloaded in Android layer
wv.setDownloadListener(DownloadListener { url, _, _, _, _ ->
if (url.startsWith("blob:")) {
wv.evaluateJavascript(javascriptInterface.getBase64StringFromBlobUrl(url), null)
}
})
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.demo">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
注意：在JavascriptInterface.kt的processBase64Data方法里面，只有
data:image/png;base64,data:application/pdf;base64,data:image/gif;base64,data:image/png;base64,