我正在构建一个包含上传照片选项的 Android webview 应用程序。单击“选择文件”按钮时，会出现使用相机与文件的选项。文件选项按预期工作。但是，在选择相机时，相机打开，用户可以拍摄照片并按复选标记，但是屏幕返回返回但仍显示“无文件”。任何想法如何解决？
这是我的意思的链接：https://imgur.com/a/f8OXCeX
这是我的 MainActivity 文件：
package com.exampleapplication.webview;
import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.appcompat.app.AppCompatActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.webkit.CookieManager;
import android.webkit.DownloadListener;
import android.webkit.URLUtil;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class MainActivity extends AppCompatActivity{
WebView webView;
private static final String TAG = MainActivity.class.getSimpleName();
private ValueCallback<Uri> mUploadMessage;
private Uri mCapturedImageURI = null;
private ValueCallback<Uri[]> mFilePathCallback;
private String mCameraPhotoPath;
private static final int INPUT_FILE_REQUEST_CODE = 1;
private static final int FILECHOOSER_RESULTCODE = 1;
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode != INPUT_FILE_REQUEST_CODE || mFilePathCallback == null) {
super.onActivityResult(requestCode, resultCode, data);
return;
}
Uri[] results = null;
// Check that the response is a good one
if (resultCode == Activity.RESULT_OK) {
if (data == null) {
// If there is not data, then we may have taken a photo
if (mCameraPhotoPath != null) {
results = new Uri[]{Uri.parse(mCameraPhotoPath)};
}
} else {
String dataString = data.getDataString();
if (dataString != null) {
results = new Uri[]{Uri.parse(dataString)};
}
}
}
mFilePathCallback.onReceiveValue(results);
mFilePathCallback = null;
return;
}
@SuppressLint({"SetJavaScriptEnabled", "WrongViewCast"})
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(com.exampleapplication.webview.R.layout.activity_main);
if(Build.VERSION.SDK_INT >=23 && (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)) {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.CAMERA}, 1);
}
webView = (WebView) findViewById(com.exampleapplication.webview.R.id.ifView);
assert webView != null;
//WebView settings
webView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
webView.setScrollbarFadingEnabled(true);
webView.getSettings().setBuiltInZoomControls(true);
webView.getSettings().setDisplayZoomControls(false);
webView.getSettings().setAllowFileAccess(true);
webView.getSettings().setSupportZoom(true);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl){
Toast.makeText(getApplicationContext(), "Failed loading app!", Toast.LENGTH_SHORT).show();
}
//Load external links in browser instead of app
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
if((String.valueOf(request.getUrl())).contains("htmldog")) {
view.loadUrl(String.valueOf(request.getUrl()));
} else {
Intent intent = new Intent(Intent.ACTION_VIEW, request.getUrl());
view.getContext().startActivity(intent);
}
return true;
}
});
String url = "https://www.htmldog.com/examples/inputfile.html";
if(null != getIntent().getData()){
url = getIntent().getData().toString();
}
webView.loadUrl(url);
webView.setWebChromeClient(new WebChromeClient(){
public boolean onShowFileChooser(WebView view, ValueCallback<Uri[]> filePath, WebChromeClient.FileChooserParams fileChooserParams) {
// Double check that we don't have any existing callbacks
if (mFilePathCallback != null) {
mFilePathCallback.onReceiveValue(null);
}
mFilePathCallback = filePath;
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
takePictureIntent.putExtra("PhotoPath", mCameraPhotoPath);
} catch (IOException ex) {
// Error occurred while creating the File
Log.e("ErrorCreatingFile", "Unable to create Image File", ex);
}
// Continue only if the File was successfully created
if (photoFile != null) {
mCameraPhotoPath = "file:" + photoFile.getAbsolutePath();
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
Uri.fromFile(photoFile));
} else {
takePictureIntent = null;
}
}
Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
contentSelectionIntent.setType("image/*");
Intent[] intentArray;
if (takePictureIntent != null) {
intentArray = new Intent[]{takePictureIntent};
} else {
intentArray = new Intent[0];
}
Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
chooserIntent.putExtra(Intent.EXTRA_TITLE, "Image Chooser");
chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);
startActivityForResult(chooserIntent, INPUT_FILE_REQUEST_CODE);
return true;
}
});
//Download listener for exporting
webView.setDownloadListener(new DownloadListener() {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimeType, long contentLength) {
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.setMimeType(mimeType);
//------------------------COOKIE!!------------------------
String cookies = CookieManager.getInstance().getCookie(url);
request.addRequestHeader("cookie", cookies);
//------------------------COOKIE!!------------------------
request.addRequestHeader("User-Agent", userAgent);
request.setDescription("Downloading file...");
request.setTitle(URLUtil.guessFileName(url, contentDisposition, mimeType));
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, URLUtil.guessFileName(url, contentDisposition, mimeType));
DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
dm.enqueue(request);
Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show();
}
});
//App rater popup message
new AppRater(this).show();
}
// Create an image file
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File imageFile = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
return imageFile;
}
//Back button returns to previous page
@Override
public boolean onKeyDown(int keyCode, @NonNull KeyEvent event){
if(event.getAction() == KeyEvent.ACTION_DOWN){
switch(keyCode){
case KeyEvent.KEYCODE_BACK:
if(webView.canGoBack()){
webView.goBack();
}else{
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}
@Override
public void onConfigurationChanged(Configuration newConfig){
super.onConfigurationChanged(newConfig);
}
}