我正在开发此应用以显示特定网页的网页视图。意图启动时将加载此页面。我想添加一个我从android教程（http://developer.android.com/reference/android/webkit/WebView.html）看到的进度条，但由于某种原因，它现在在创建此意图时崩溃了我的应用程序。有什么建议？谢谢！
这是我在logcat中的错误消息：
10-01 13:52:35.679: E/AndroidRuntime(273): FATAL EXCEPTION: main
10-01 13:52:35.679: E/AndroidRuntime(273): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Depauw.dpuhelpdesk/ com.Depauw.dpuhelpdesk.accounts_activity_mealplan}: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.os.Handler.dispatchMessage(Handler.java:99)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.os.Looper.loop(Looper.java:123)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread.main(ActivityThread.java:4627)
10-01 13:52:35.679: E/AndroidRuntime(273): at java.lang.reflect.Method.invokeNative(Native Method)
10-01 13:52:35.679: E/AndroidRuntime(273): at java.lang.reflect.Method.invoke(Method.java:521)
10-01 13:52:35.679: E/AndroidRuntime(273): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-01 13:52:35.679: E/AndroidRuntime(273): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-01 13:52:35.679: E/AndroidRuntime(273): at dalvik.system.NativeStart.main(Native Method)
10-01 13:52:35.679: E/AndroidRuntime(273): Caused by: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
10-01 13:52:35.679: E/AndroidRuntime(273): at com.android.internal.policy.impl.PhoneWindow.requestFeature(PhoneWindow.java:172)
10-01 13:52:35.679: E/AndroidRuntime(273): at com.Depauw.dpuhelpdesk.accounts_activity_mealplan.Initialize(accounts_activity_mealplan.java:35)
10-01 13:52:35.679: E/AndroidRuntime(273): at com.Depauw.dpuhelpdesk.accounts_activity_mealplan.onCreate(accounts_activity_mealplan.java:23)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-01 13:52:35.679: E/AndroidRuntime(273): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
10-01 13:52:35.679: E/AndroidRuntime(273): ... 11 more
崩溃的新代码：
package com.Depauw.dpuhelpdesk;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
@SuppressLint("SetJavaScriptEnabled")
public class accounts_activity_mealplan extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.webview_main);
Initialize();
}
private void Initialize(){
WebView mainWebView = (WebView) findViewById(R.id.webView1);
WebSettings webSettings = mainWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
// Let's display the progress in the activity title bar, like the
// browser app does.
getWindow().requestFeature(Window.FEATURE_PROGRESS);
mainWebView.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
mainWebView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress with different scales.
// The progress meter will automatically disappear when we reach 100%
activity.setProgress(progress * 1000);
}
});
mainWebView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
mainWebView.loadUrl("http://www.depauw.edu/studentlife/campusliving/diningoptions/?plans.html");
mainWebView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
}
}
此代码是我在编辑上述新代码之前开始的：
package com.Depauw.dpuhelpdesk;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
@SuppressLint("SetJavaScriptEnabled")
public class accounts_activity_mealplan extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.webview_main);
Initialize();
}
private void Initialize(){
WebView mainWebView = (WebView) findViewById(R.id.webView1);
WebSettings webSettings = mainWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mainWebView.setWebViewClient(new MyCustomWebViewClient());
mainWebView.loadUrl("http://www.depauw.edu/studentlife/campusliving/diningoptions/?plans.html");
mainWebView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
}
private class MyCustomWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
}
答案 0 :(得分：0)
以下是在webview上创建加载栏的示例。使用％
的文本package com.example.webview;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class WebviewActivity extends Activity {
/** onCreate() is called at start of activity */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final WebView webview = new WebView(this);
setContentView(webview);
webview.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress differently
// The indicator disappears when 100% is reached
Toast.makeText(activity, Integer.toString(progress) + "%", Toast.LENGTH_SHORT).show();
}
});
webview.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Error! " + description, Toast.LENGTH_SHORT).show();
}
public void onPageFinished(WebView view, String url)
{
Toast.makeText(activity, url, Toast.LENGTH_SHORT).show();
}
});
webview.loadUrl("http://gmaps-samples.googlecode.com/svn/trunk/articles-android-webmap/simple-android-map.html");
}
}
答案 1 :(得分：0)
尝试以下代码。
public class StandardWebView extends Activity {
// Declare Variables
WebView webview;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Prepare the progress bar
requestWindowFeature(Window.FEATURE_PROGRESS);
// Get the view from webview.xml
setContentView(R.layout.webview);
// Locate the WebView in webview.xml
webview = (WebView) findViewById(R.id.webview);
// Enable Javascript to run in WebView
webview.getSettings().setJavaScriptEnabled(true);
// Allow Zoom in/out controls
webview.getSettings().setBuiltInZoomControls(true);
// Zoom out the best fit your screen
webview.getSettings().setLoadWithOverviewMode(true);
webview.getSettings().setUseWideViewPort(true);
// Load URL
webview.loadUrl("http://www.yoururl.com");
// Show the progress bar
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
setProgress(progress * 100);
}
});
// Call private class InsideWebViewClient
webview.setWebViewClient(new InsideWebViewClient());
}
private class InsideWebViewClient extends WebViewClient {
@Override
// Force links to be opened inside WebView and not in Default Browser
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
}
来源：http://www.androidbegin.com/tutorial/implementing-webview-in-android/