Android - 在 WebView 中选择文件按钮

Question

我在 WebView 中加载了一个页面时遇到问题 - 我不打算发布整个应用程序的代码，因为我的问题非常具体：我的 HTML 页面中的“选择文件”按钮适用于Android Studio 创建了模拟器，但别无他处。

该按钮运行此代码：

 <input type='file' id='fileInput' accept='text/plain' onchange='openFile(event);'>
var openFile = function(event) {
        var input = event.target;

        var reader = new FileReader();
        reader.onload = function(e){
            /* various string parsing */
        };
        reader.readAsText(input.files[0]);
};

这在我的 API 23 模拟器上工作得很好：单击按钮打开设备的默认文件选择器以选择一个文件。但是，在我的 API 16 实际手机上，单击此按钮没有任何反应。此外，在 API 18 的 Genymotion 模拟器上，单击按钮什么也不做。我可以做些什么来解决这个问题吗？该按钮在我的手机和 Genymotion 模拟器上都没有产生任何错误消息，它就在那里，什么也没有发生。

我需要该应用程序在允许语音到文本的设备上运行，所以我不能只使用模拟器，只要我愿意。

原文由 user3475234 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

设置 WebChromeClient 选择文件

代码

import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.webkit.JavascriptInterface;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;
import org.apache.http.util.EncodingUtils;

public class BrowserScreen extends Activity {

    private WebView webView;
    private String url = "url";

    private ValueCallback<Uri> mUploadMessage;
    private final static int FILECHOOSER_RESULTCODE = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.browser_activity);
        initFields();
        setListeners();
    }

    public void initFields() {
        // TODO Auto-generated method stub

        webView = (WebView) findViewById(R.id.webView1);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setBuiltInZoomControls(true);
        webView.getSettings().setAllowFileAccess(true);
    }

    public void setListeners() {
        // TODO Auto-generated method stub

        webView.setWebViewClient(new WebViewClient() {
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {

                webView.loadUrl("about:blank");

                view.clearHistory();
            }
        });

        webView.setWebChromeClient(new WebChromeClient() {
            public void onProgressChanged(WebView view, int progress) {

            }

            //The undocumented magic method override
            //Eclipse will swear at you if you try to put @Override here
            // For Android 3.0+
            public void openFileChooser(ValueCallback<Uri> uploadMsg) {

                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("image/*");
                startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
            }

            // For Android 3.0+
            public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("*/*");
                startActivityForResult(
                        Intent.createChooser(i, "File Browser"),
                        FILECHOOSER_RESULTCODE);
            }

            //For Android 4.1
            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("image/*");
                startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);

            }
        });

            webView.loadUrl(url);

        final MyJavaScriptInterface myJavaScriptInterface
                = new MyJavaScriptInterface(this);
        webView.addJavascriptInterface(myJavaScriptInterface, "AndroidFunction");
    }

    @Override
    public void onBackPressed() {
        // TODO Auto-generated method stub

        if (webView.canGoBack() == true) {
            webView.goBack();
        } else {
            super.onBackPressed();
        }
    }

    public class MyJavaScriptInterface {
        Context mContext;

        MyJavaScriptInterface(Context c) {
            mContext = c;
        }

        @JavascriptInterface
        public void showToast(String toast) {
            Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
            // webView.loadUrl("javascript:document.getElementById(\"Button3\").innerHTML = \"bye\";");
        }

        @JavascriptInterface
        public void openAndroidDialog() {
            AlertDialog.Builder myDialog
                    = new AlertDialog.Builder(BrowserScreen.this);
            myDialog.setTitle("DANGER!");
            myDialog.setMessage("You can do what you want!");
            myDialog.setPositiveButton("ON", null);
            myDialog.show();
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode,
                                    Intent intent) {
        if (requestCode == FILECHOOSER_RESULTCODE) {
            if (null == mUploadMessage) return;
            Uri result = intent == null || resultCode != RESULT_OK ? null
                    : intent.getData();
            mUploadMessage.onReceiveValue(result);
            mUploadMessage = null;
        }
    }
}

原文由 Kanaiya Katarmal 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

已接受的答案对我不起作用。我从 Google Chromium Samples 找到了新答案。

 public class WebViewActivity extends AppCompatActivity {

    ActivityWebviewBinding binding;

    public static final int INPUT_FILE_REQUEST_CODE = 1;
    private ProgressDialog progressDialog;
    private ValueCallback<Uri[]> mFilePathCallback;
    private String mCameraPhotoPath;

    @SuppressLint("SetJavaScriptEnabled")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = DataBindingUtil.setContentView(this, R.layout.activity_webview);

        setSupportActionBar(binding.toolbar);

        if (getSupportActionBar() != null) {
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setTitle(getString(R.string.button_register_now));
        }

        progressDialog = new ProgressDialog(WebViewActivity.this);
        progressDialog.setMessage("Loading...");
        progressDialog.show();

        WebSettings webSettings = binding.webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setSupportZoom(true);
        webSettings.setBuiltInZoomControls(true);
        webSettings.setDisplayZoomControls(false);
        webSettings.setAllowFileAccess(true);
        webSettings.setLoadWithOverviewMode(true);
        webSettings.setUseWideViewPort(true);

        binding.webView.setWebViewClient(new WebViewClient() {

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                final Uri uri = Uri.parse(url);
                return handleUri(uri);
            }

            @TargetApi(Build.VERSION_CODES.N)
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
                final Uri uri = request.getUrl();
                return handleUri(uri);
            }

            private boolean handleUri(final Uri uri) {

                if (uri != null) {

                    Log.i("TAG", "Uri =" + uri);

                    // Based on some condition you need to determine if you are going to load the url
                    // in your web view itself or in a browser.
                    // You can use `host` or `scheme` or any part of the `uri` to decide.
                    if (uri.getLastPathSegment() != null) {
                        if (uri.getLastPathSegment().contains("p1_business_part1.php")) {
                            finish();
                            startActivity(new Intent(WebViewActivity.this, LoginActivity.class));
                            return false;
                        }
                    } else {
                        binding.webView.loadUrl(uri.toString());
                        return true;
                    }
                }

                return false;
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                if (progressDialog.isShowing()) {
                    progressDialog.dismiss();
                }
            }

            @Override
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                Toast.makeText(WebViewActivity.this, "Error:" + description, Toast.LENGTH_SHORT).show();
                view.loadUrl("about:blank");
            }
        });
        binding.webView.setWebChromeClient(new WebChromeClient() {

            public boolean onShowFileChooser(
                    WebView webView, ValueCallback<Uri[]> filePathCallback,
                    WebChromeClient.FileChooserParams fileChooserParams) {
                if (mFilePathCallback != null) {
                    mFilePathCallback.onReceiveValue(null);
                }
                mFilePathCallback = filePathCallback;

                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("TAG", "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;
            }
        });

        binding.webView.loadUrl("your_url");
    }

    /**
     * More info this method can be found at
     * http://developer.android.com/training/camera/photobasics.html
     *
     * @return
     * @throws IOException
     */
    private File createImageFile() throws IOException {
        // Create an image file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        return File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );
    }

    @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;
    }

    @Override
    public void onBackPressed() {
        // TODO Auto-generated method stub

        if (binding.webView.canGoBack()) {
            binding.webView.goBack();
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        finish();
        return super.onOptionsItemSelected(item);
    }
}

希望它能帮助别人。

谢谢你。

原文由 Pratik Butani 发布，翻译遵循 CC BY-SA 4.0 许可协议