我正在使用以下代码在我的 Android 应用程序中显示 Web 视图。
package com.company.myapp;
import com.google.android.apps.analytics.GoogleAnalyticsTracker;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class ArticlesActivity extends Activity {
/** Initialize the Google Analytics Tracker */
GoogleAnalyticsTracker tracker;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_PROGRESS);
getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
WebView webview = new WebView(this);
setContentView(webview);
setProgressBarVisibility(true);
webview.getSettings().setJavaScriptEnabled(true);
webview.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
final Activity activity = this;
tracker = GoogleAnalyticsTracker.getInstance();
// Start the tracker, updating google every 20 seconds
tracker.start((String) getText(R.string.analyticsID), 20, this);
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
activity.setProgress(progress * 100 );
}
});
webview.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webview.loadUrl("http://www.google.com");
}
@Override
public void onResume() {
tracker.trackPageView("ArticlesActivity");
super.onResume();
}
@Override
protected void onDestroy() {
super.onDestroy();
// Stop the tracker when it is no longer needed.
tracker.stop();
}
}
如果历史记录存在,我需要启用后退按钮来后退,而不是仅仅退出网络视图。
我尝试过许多不同的代码示例,例如这样 https://stackoverflow.com/questions/6077141/android-webview-how-to-code-the-back-button但无法让任何人工作。当按下后退按钮时,应用程序就会关闭。
这是我的带有后退按钮代码的代码,但按下后退按钮时它只会使应用程序崩溃:
package com.company.myapp;
import com.google.android.apps.analytics.GoogleAnalyticsTracker;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class ArticlesActivity extends Activity {
WebView webview;
/** Initialize the Google Analytics Tracker */
GoogleAnalyticsTracker tracker;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_PROGRESS);
getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
WebView webview = new WebView(this);
setContentView(webview);
setProgressBarVisibility(true);
webview.getSettings().setJavaScriptEnabled(true);
webview.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
final Activity activity = this;
tracker = GoogleAnalyticsTracker.getInstance();
// Start the tracker, updating google every 20 seconds
tracker.start((String) getText(R.string.analyticsID), 20, this);
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
activity.setProgress(progress * 100 );
}
});
webview.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webview.loadUrl("http://www.google.com");
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
webview.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public void onResume() {
tracker.trackPageView("ArticlesActivity");
super.onResume();
}
@Override
protected void onDestroy() {
super.onDestroy();
// Stop the tracker when it is no longer needed.
tracker.stop();
}
}
有人可以帮我解决吗?