尝试打开具有Windows身份验证的本地托管网站时，在进度对话框的show（）函数中获取空指针异常。在＆＃34; EDIT＆＃34;中给出的详细信息部分：
我的webView类如下：
Web.java
public class Web extends Activity {
private WebView webView;
final Activity activity = this;
public Uri imageUri;
ProgressDialog progressDialog;
private static final int FILECHOOSER_RESULTCODE = 2888;
private ValueCallback<Uri> mUploadMessage;
private Uri mCapturedImageURI = null;
public static final int REQUEST_SELECT_FILE = 100;
public ValueCallback<Uri[]> uploadMessage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.activity_web);
webView = (WebView) findViewById(R.id.webView1);
webView.setWebViewClient(new MyWebViewClient());
String url = "http://192.168.*.*";
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl(url);
webView.getSettings().setRenderPriority(RenderPriority.HIGH);
webView.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
webView.getSettings().setLoadWithOverviewMode(true);
//webView.getSettings().setUseWideViewPort(true);
//Other webview settings
webView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
webView.setScrollbarFadingEnabled(false);
webView.getSettings().setBuiltInZoomControls(true);
webView.getSettings().setPluginState(PluginState.ON);
webView.getSettings().setAllowFileAccess(true);
webView.getSettings().setSupportZoom(true);
webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
webView.setDownloadListener(new DownloadListener()
{
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength)
{
//for downloading directly through download manager
final String filename= URLUtil.guessFileName(url, contentDisposition, mimetype);
Request request = new Request(Uri.parse(url));
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename);
DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
dm.enqueue(request);
}
});
}
private class MyWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return false;
}
public void onLoadResource (WebView view, String url) {
// if url contains string androidexample
// Then show progress Dialog
if(progressDialog==null)
{
// in standard case YourActivity.this
progressDialog = new ProgressDialog(Web.this);
progressDialog.setMessage("Loading...");
}
progressDialog.show();}
// Called when all page resources loaded
public void onPageFinished(WebView view, String url) {
try{
// Close progressDialog
if (progressDialog.isShowing()) {
progressDialog.dismiss();
progressDialog = null;
}
}catch(Exception exception){
exception.printStackTrace();
}
}
}
public class MyWebChromeClient extends WebChromeClient {
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType){
// Update message
mUploadMessage = uploadMsg;
try{
// Create AndroidExampleFolder at sdcard
File imageStorageDir = new File(
Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES)
, "r2Reviews");
if (!imageStorageDir.exists()) {
// Create AndroidExampleFolder at sdcard
imageStorageDir.mkdirs();
}
// Create camera captured image file path and name
File file = new File(
imageStorageDir + File.separator + "IMG_"
+ String.valueOf(System.currentTimeMillis())
+ ".jpg");
mCapturedImageURI = Uri.fromFile(file);
// Camera capture image intent
final Intent captureIntent = new Intent(
android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, mCapturedImageURI);
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("image/*");
// Create file chooser intent
Intent chooserIntent = Intent.createChooser(i, "Image Chooser");
// Set camera intent to file chooser
chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS
, new Parcelable[] { captureIntent });
// On select image call onActivityResult method of activity
startActivityForResult(chooserIntent, FILECHOOSER_RESULTCODE);
}
catch(Exception e){
Toast.makeText(getBaseContext(), "Exception:"+e,
Toast.LENGTH_LONG).show();
}
}
// openFileChooser for Android < 3.0
public void openFileChooser(ValueCallback<Uri> uploadMsg){
openFileChooser(uploadMsg, "");
}
//openFileChooser for other Android versions
public void openFileChooser(ValueCallback<Uri> uploadMsg,
String acceptType,
String capture) {
openFileChooser(uploadMsg, acceptType);
}
// The webPage has 2 filechoosers and will send a
// console message informing what action to perform,
// taking a photo or updating the file
public boolean onConsoleMessage(ConsoleMessage cm) {
onConsoleMessage(cm.message(), cm.lineNumber(), cm.sourceId());
return true;
}
public void onConsoleMessage(String message, int lineNumber, String sourceID) {
//Log.d("androidruntime", "Show console messages, Used for debugging: " + message);
}}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (webView.canGoBack()) {
webView.goBack();
} else {
Intent i = new Intent(this, MainActivity.class);
startActivity(i);
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}
@SuppressLint("NewApi")
protected void onActivityResult(int requestCode, int resultCode, Intent data){
if(requestCode==FILECHOOSER_RESULTCODE)
{
if (null == this.mUploadMessage) {
return;
}
Uri result=null;
try{
if (resultCode != RESULT_OK) {
result = null;
} else {
// retrieve from the private variable if the intent is null
result = data == null ? mCapturedImageURI : data.getData();
}
}
catch(Exception e)
{
Toast.makeText(getApplicationContext(), "activity :"+e,
Toast.LENGTH_LONG).show();
}
mUploadMessage.onReceiveValue(result);
mUploadMessage = null;
}
}}
编辑：
试图访问本地托管的网站，如：＆＃34; http://192.168。*。**＆＃34;其中包括添加几行代码的Windows身份验证：
public void onReceivedHttpAuthRequest(WebView view,
HttpAuthHandler handler, String host, String realm) {
handler.proceed("DOMAIN\\username", "password");
}
但不幸的是，由于空指针异常描述为：＆＃34;尝试在progressDialog.show（）上调用虚方法，我得到了强制关闭错误;＆＃34;
关于如何解决这个问题的任何线索.. ?? 谢谢大家。
答案 0 :(得分：2)
现在阻止全视图不是现在的首选方式。如果您显示进度对话框，并且不允许在外面按下或触摸时关闭。用户将被黑暗大修和装载机阻挡，所以我认为你应该使用以下方式来显示装载机。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone" />
<RelativeLayout
android:id="@+id/layout_loader"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone"
tools:visibility="visible"
android:gravity="center_horizontal">
<android.support.v4.widget.ContentLoadingProgressBar
android:id="@+id/address_looking_up"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:visibility="visible"/>
</RelativeLayout>
</LinearLayout>
和Java文件
wvLoad.setWebViewClient（new WebViewClient（）{
//If you will not use this method url links are open in new browser not in webview
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
//Show loader on url load
public void onLoadResource (WebView view, String url) {
}
public void onPageFinished(WebView view, String url) {
try{
loader_layout.setVisibility(View.GONE);
wvLoad.setVisibility(View.VISIBLE);
}catch(Exception exception){
exception.printStackTrace();
}
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
loader_layout.setVisibility(View.VISIBLE);
wvLoad.setVisibility(View.GONE);
}
});
// Javascript enabled on webview
wvLoad.getSettings().setJavaScriptEnabled(true);
//Load url in webview
wvLoad.loadUrl(url);
答案 1 :(得分：1)
您的progress view是全球性的，initialize只有一次，而不只是show或dismiss：
if(progressDialog == null){
progressDialog = new ProgressDialog(Web.this);
progressDialog.setMessage("Loading...");
}
您现在正在做的是show()方法也处于if状态，这就是它仅在开始时显示的原因。