在上传不工作之前，Android webview中的图像预览

好吧，我正在制作一个Android webview应用程序，我在这里面临一个问题。 我试图在上传之前在网页上预览我的图像这是我使用的html and java script代码。

      $(document).ready(function(){ var preview = $(".upload-preview img"); $(".file").change(function(event){ var input = $(event.currentTarget); var file = input[0].files[0]; var reader = new FileReader(); reader.onload = function(e){ image_base64 = e.target.result; preview.attr("src", image_base64); }; reader.readAsDataURL(file); }); });    
  
    

这里是小提琴

它几乎适用于所有浏览器（即Firefox，Chrome和IE），没有任何错误或警告。 这是firefox的快照（在上传前显示预览）

现在，每当我尝试在Android webview中打开它时，它没有显示图像预览，它显示了这样的东西

我不知道什么是错的，我启用了javascript并包含了jquery 。 它有一天让我疯狂。

这是我的android webview代码。

 package net.kaosfield.wv1; import my.functions.MyFunctions; import android.net.Uri; import android.os.Bundle; import android.annotation.SuppressLint; import android.app.Activity; import android.content.Intent; import android.util.Log; import android.view.KeyEvent; import android.view.Menu; import android.webkit.ValueCallback; import android.webkit.WebChromeClient; import android.webkit.WebViewClient; import android.webkit.WebSettings; import android.webkit.WebView; import android.webkit.JsResult; import android.content.Intent; import com.google.android.gcm.GCMRegistrar; public class MainActivity extends Activity { Activity activity = MainActivity.this; private WebView webView = null; private ValueCallback uploadMessage; private final static int FILECHOOSER_RESULTCODE = 1; private static String registrationId = ""; private MyFunctions myFunctions; @Override protected void onActivityResult(int requestCode, int resultCode, Intent intent) { if (requestCode == FILECHOOSER_RESULTCODE) { if (uploadMessage == null) return; Uri result = intent == null || resultCode != RESULT_OK ? null : intent.getData(); uploadMessage.onReceiveValue(result); uploadMessage = null; } } @SuppressLint("SetJavaScriptEnabled") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myFunctions = new MyFunctions(activity); webView = (WebView) findViewById(R.id.webview); webView.setInitialScale(myFunctions.setWebViewScale()); WebSettings webSettings = webView.getSettings(); webSettings.setJavaScriptEnabled(true); webView.setWebViewClient(new WebViewClient() { public boolean shouldOverrideUrlLoading(WebView view, String url) { if (url.startsWith("net.kaosfield.wv1:")) { Log.d("wv1", url); return true; } return false; } @Override public void onPageFinished(WebView view, String url) { Log.d("wv1", "onPageFinished"); String argument = "def"; view.loadUrl("javascript:alert(window.method(\"" + argument + "\"))"); } }); webView.setWebChromeClient(new WebChromeClient() { @Override public boolean onJsAlert(WebView view, String url, String message, JsResult result) { if (message.equals("net.kaosfield.wv1")) { try { Log.d("wv1", "url: " + url + ", message: " + message); return true; } finally { result.confirm(); // in order not to alert } } else { return false; } } // For Android 3.0+ @SuppressWarnings("unused") public void openFileChooser(ValueCallback uploadMsg) { uploadMessage = uploadMsg; Intent i = new Intent(Intent.ACTION_GET_CONTENT); i.addCategory(Intent.CATEGORY_OPENABLE); i.setType("image/*"); MainActivity.this.startActivityForResult( Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE); } // For Android 3.0+ @SuppressWarnings("unused") public void openFileChooser(ValueCallback uploadMsg, String acceptType) { uploadMessage = uploadMsg; Intent i = new Intent(Intent.ACTION_GET_CONTENT); i.addCategory(Intent.CATEGORY_OPENABLE); i.setType("image/*"); MainActivity.this.startActivityForResult( Intent.createChooser(i, "File Browser"), FILECHOOSER_RESULTCODE); } // For Android 4.1 @SuppressWarnings("unused") public void openFileChooser(ValueCallback uploadMsg, String acceptType, String capture) { uploadMessage = uploadMsg; Intent i = new Intent(Intent.ACTION_GET_CONTENT); i.addCategory(Intent.CATEGORY_OPENABLE); i.setType("image/*"); MainActivity.this.startActivityForResult( Intent.createChooser(i, "File Chooser"), MainActivity.FILECHOOSER_RESULTCODE); } }); webView.loadUrl("http://blue.genetechz.com/qadir/test.php"); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { // Check if the key event was the Back button and if there's history if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack()) { webView.goBack(); return true; } // If it wasn't the Back key or there's no web page history, bubble up // to the default // system behavior (probably exit the activity) return super.onKeyDown(keyCode, event); } } 

Answer 1

您必须在onActivityRestult上进行此更改，因为从库中返回的URL不正确：

 @Override protected void onActivityResult(int requestCode, int resultCode, Intent intent) { if (requestCode == FILECHOOSER_RESULTCODE) { if (uploadMessage == null) return; Uri result = intent == null || resultCode != RESULT_OK ? null : intent.getData(); if (result!=null){ String filePath = null; if ("content".equals(result.getScheme())) { Cursor cursor = this.getContentResolver().query(result, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA }, null, null, null); cursor.moveToFirst(); filePath = cursor.getString(0); cursor.close(); } else { filePath = result.getPath(); } Uri myUri = Uri.parse(filePath); uploadMessage.onReceiveValue(myUri); } else { uploadMessage.onReceiveValue(result); } uploadMessage = null; } } 

现在，即使您从图库中选择图像，它也会返回带有file:///格式的url。