WebView选择文件和Activity休闲

Question

[有一个应用程序，将用户入职流程实现为网页，并在嵌入式WebView中显示。流程步骤之一是上传文件。

通过使用网页上的<input/>标记并通过覆盖的WebChromeClient.onShowFileChooser(..., filePathCallback: ValueCallback<Array<Uri>>?, ...)进一步处理它，最终触发了应该由平台File-Chooser-Activity提供的startActivityForResult(...)来实现（对于不同的供应商/版本）。

和往常一样，一切正常，直到活动被销毁：）

问题是，在应用程序活动的顶部启动File-Chooser-Activity时，最后一个活动可能会被销毁（由于缺少资源，轮换等，系统会将该活动销毁）。然后，我们拥有其filePathCallback的WebView也将被销毁。这意味着应用程序在获取所选文件的URI（在filePathCallback上）时，此时没有有效的onActivityResult。

您如何解决此问题？

我创建了一个简单的项目来单独表示问题，请随时查看：https://github.com/allco/WebViewFileChooseIssue

这里有一些视频：

http://www.youtube.com/watch?v=9mnd0lT9lZI

案例2演示了问题，即使选择完成，应用仍然显示“未选择文件”。

这里是带有项目密钥文件的剪切片段：

class MainActivity : AppCompatActivity() {

    companion object {
        const val REQ_CODE_CHOOSER = 1
    }

    val unencodedHtml = "<input type=file>"
    var webViewFileChooseCallback: ValueCallback<Array<Uri>>? = null

    private val webClient = object : WebViewClient() {
        ...
    }



    private val chromeClient = object : WebChromeClient() {
        ...
        override fun onShowFileChooser(
            webView: WebView,
            filePathCallback: ValueCallback<Array<Uri>>?,
            fileChooserParams: FileChooserParams?
        ): Boolean {
            if (filePathCallback == null) return false
            webViewFileChooseCallback = filePathCallback
            startFileChooserActivity("*/*")
            return true
        }
    }

    fun startFileChooserActivity(mimeType: String) {
        val intent = Intent(Intent.ACTION_GET_CONTENT)
        intent.type = mimeType
        intent.addCategory(Intent.CATEGORY_OPENABLE)

        // special intent for Samsung file manager
        val sIntent = Intent("com.sec.android.app.myfiles.PICK_DATA")
        // if you want any file type, you can skip next line
        sIntent.putExtra("CONTENT_TYPE", mimeType)
        sIntent.addCategory(Intent.CATEGORY_DEFAULT)

        val chooserIntent: Intent
        if (packageManager.resolveActivity(sIntent, 0) != null) {
            // it is device with Samsung file manager
            chooserIntent = Intent.createChooser(sIntent, "Open file")
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, arrayOf(intent))
        } else {
            chooserIntent = Intent.createChooser(intent, "Open file")
        }

        try {
            startActivityForResult(chooserIntent, REQ_CODE_CHOOSER)
        } catch (ex: android.content.ActivityNotFoundException) {
            Toast.makeText(applicationContext, "No suitable File Manager was found.", Toast.LENGTH_SHORT).show()
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val webView = findViewById<WebView>(R.id.webView)
        webView.webChromeClient = chromeClient
        webView.webViewClient = webClient

        if (savedInstanceState == null) {
            val encodedHtml = Base64.encodeToString(unencodedHtml.toByteArray(), Base64.NO_PADDING)
            webView.loadData(encodedHtml, "text/html", "base64")
        } else {
            webView.restoreState(savedInstanceState)
        }
    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        findViewById<WebView>(R.id.webView).saveState(outState)
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        when {
            requestCode == REQ_CODE_CHOOSER && resultCode == Activity.RESULT_OK && data != null -> {
                val uri = when {
                    data.dataString != null -> arrayOf(Uri.parse(data.dataString))
                    data.clipData != null -> (0 until data.clipData!!.itemCount)
                        .mapNotNull { data.clipData?.getItemAt(it)?.uri }
                        .toTypedArray()
                    else -> null
                }
                webViewFileChooseCallback?.onReceiveValue(uri)
            }
            else -> super.onActivityResult(requestCode, resultCode, data)
        }
    }
}

Answer 1

将相关数据存储在onSaveInstanceState()中并在onCreate()中读取]