我在我的代码中添加了一个进度条来显示 webview 的进度。但是进度条不显示。我在哪里犯错？请指教。我已经复制了下面的完整代码。这段代码有 4 个按钮，只要单击一个按钮，webview 就会显示该特定站点。每当加载网站时，我都试图添加进度条。
public class MainActivity extends Activity {
/** Called when the activity is first created. */
ImageButton imageButton;
ProgressBar progressBar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
atebutton();
blogsbutton();
searchbutton();
minkbutton();
techmbutton();
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
// webView.setInitialScale(67);
WebSettings webSettings = webView.getSettings();
webSettings.setBuiltInZoomControls(true);
webSettings.setJavaScriptEnabled(true);
webView.setVerticalScrollBarEnabled(false);
webView.setHorizontalScrollBarEnabled(false);
webView.setWebViewClient(new WebViewClient() {
public void onProgressChanged(WebView view, int progress)
{
if(progress < 100 && progressBar.getVisibility() == ProgressBar.GONE){
progressBar.setVisibility(ProgressBar.VISIBLE);
}
progressBar.setProgress(progress);
if(progress == 100) {
progressBar.setVisibility(ProgressBar.GONE);
}
}
@Override
public void onReceivedLoginRequest(WebView view, String realm,
String account, String args) {
System.err.println(realm);
System.err.println(account);
System.out.println(args); }
@Override
public void onReceivedError( WebView view, int errorCode, String description, String failingUrl ) {
Toast.makeText(view.getContext(), "Unknown Error", Toast.LENGTH_LONG).show();
System.err.println(errorCode + " - " + description + "-" + failingUrl);
}
@Override
public void onReceivedSslError( WebView view, SslErrorHandler handler, SslError error ) {
System.err.println("SSL ERROR");
handler.proceed();
}
@SuppressLint({ "InlinedApi", "NewApi" })
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
if( (url.contains(".pdf" )) || (url.contains(".doc" )) ||
(url.contains(".xls" )) || (url.contains(".ppt" ))|| (url.contains(".txt" ))){
Intent DownloadIntent = null;
try {
DownloadIntent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME);
DownloadIntent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
} catch (URISyntaxException e) {
Log.e("Link Tag", e.getMessage());
}
startActivity(DownloadIntent);
}
return true;
}
@Override
public void onPageFinished(WebView view, String url) {
// TODO Auto-generated method stub
super.onPageFinished(view, url);
progressBar.setVisibility(View.GONE);
}
@Override
public void onReceivedHttpAuthRequest(WebView view, final HttpAuthHandler handler, final String host,
String realm) {
System.err.println("HTTP auth request");
final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
if (handler.useHttpAuthUsernamePassword()) {
if (preferences.contains("username")) {
handler.proceed(preferences.getString("username", null), preferences.getString("password", null));
return;
}
}
new Dialog(MainActivity.this){
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTitle(host);
setContentView(R.layout.credentials);
final EditText userName = (EditText) findViewById(R.id.UserName);
final EditText password = (EditText) findViewById(R.id.Password);
userName.setText(preferences.getString("username", ""));
password.setText(preferences.getString("password", ""));
Button button = (Button) findViewById(R.id.GoButton);
button.setOnClickListener(new Button.OnClickListener(){
public void onClick(View v) {
String userName2 = userName.getText().toString();
String password2 = password.getText().toString();
Editor edit = preferences.edit();
edit.putString("username", userName2);
edit.putString("password", password2);
edit.commit();
handler.proceed(userName2, password2);
dismiss();
}});
}
}.show();
}
});
String url;
if (getIntent().hasExtra("url")) {
url = getIntent().getStringExtra("url");
} else {
url = "https://kee.mahindrasatyam.com/_layouts/mobile/mobilesearch.aspx";
}
webView.loadUrl(url);
MainActivity.this.progressBar.setProgress(0);
}
private void techmbutton() {
// TODO Auto-generated method stub
imageButton = (ImageButton) findViewById(R.id.imageButton5);
imageButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
webView.loadUrl("http://techmahindra.com");
}
});}
private void blogsbutton() {
// TODO Auto-generated method stub
imageButton = (ImageButton) findViewById(R.id.imageButton2);
imageButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
webView.loadUrl("https://blogs.mahindrasatyam.com/m");
}
});}
private void searchbutton() {
// TODO Auto-generated method stub
imageButton = (ImageButton) findViewById(R.id.imageButton3);
imageButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
webView.loadUrl("https://kee.mahindrasatyam.com/_layouts/mobile/mobilesearch.aspx");
}
});}
private void minkbutton() {
// TODO Auto-generated method stub
imageButton = (ImageButton) findViewById(R.id.imageButton4);
imageButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
webView.loadUrl("https://mink.mahindrasatyam.com/m");
}
});}
private void atebutton() {
// TODO Auto-generated method stub
imageButton = (ImageButton) findViewById(R.id.imageButton1);
imageButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
WebView webView = (WebView) findViewById(R.id.MyWebView);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setMax(100);
webView.loadUrl("https://ate.mahindrasatyam.com/m");
}
});}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
Intent intent = new Intent(MainActivity.this, MainActivity.class);
startActivity(intent);
return true;
}