每当我按操作栏中的按钮时，应用程序崩溃

Question

每当我按下操作栏中的按钮时，我的应用程序就会崩溃，但仅当该按钮与Webview有关时，它才会发生。 但是web视图确实加载网页的onCreate方法仍然可以工作。

public boolean onOptionsItemSelected(MenuItem item) {
    setContentView(R.layout.activity_main); 
    mWebview =(WebView) findViewById(R.id.webView1);
    switch (item.getItemId()) {
    // If button 1 is pressed
    case R.id.about:
        // Toast Message
        Toast.makeText(this, "App made by Robin Flikkema & Sander ten Hove",
        Toast.LENGTH_LONG).show();
        break;
    // If Share is pressed
    case R.id.menu_share:
        // Toast message
        Toast.makeText(this, "Roosterwijzigingen delen",
        Toast.LENGTH_SHORT).show();
        // Making share selector
        String shareBody = "Er vervallen nieuwe lessen! Check het uit, met de Eemsdeltacollege Roosterwijzigingen App.";
        Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
            sharingIntent.setType("text/plain");
            sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Eemsdeltacollege Roosterwijzigingen");
            sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody);
            startActivity(Intent.createChooser(sharingIntent, getResources().getString(R.string.share_using)));
        break;
    // If Next is pressed
    case R.id.menu_next:
        // Toast message
        Toast.makeText(this, "Morgen",
        Toast.LENGTH_SHORT).show();
        // Calculate Date
        Calendar cal=Calendar.getInstance();
        int currentDay=cal.get(Calendar.DAY_OF_MONTH);
        //Set the date to 1 day
        cal.set(Calendar.DAY_OF_MONTH, currentDay+1);
        while (cal.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY || 
                cal.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) {
           cal.add(Calendar.DATE, 1);
       }
        Date DateDate = cal.getTime();
        SimpleDateFormat postFormater = new SimpleDateFormat("dd-M-yyyy"); 

        String newDateStr = postFormater.format(DateDate); 
        // Set URL
        mWebview .loadUrl("http://divers.ommelandercollege.nl/webportalen/dagrooster.php?datum="+newDateStr);
        setContentView(mWebview );
        break;
    // If Refresh is pressed
    case R.id.menu_refresh:
        // Toast message
        Toast.makeText(this, "Roosterwijzigingen ophalen.",
        Toast.LENGTH_SHORT).show();
        // Load URL
        mWebview .loadUrl("http://divers.ommelandercollege.nl/webportalen/dagrooster.php");
        setContentView(mWebview );
        break;
    // If Overmorgen is pressed
    case R.id.menu_nextt:
        // Toast message
        Toast.makeText(this, "Overmorgen",
        Toast.LENGTH_SHORT).show();
        // Calculate Date
        Calendar cal1=Calendar.getInstance();
        int currentDay1=cal1.get(Calendar.DAY_OF_MONTH);
        //Set the date to 1 day
        cal1.set(Calendar.DAY_OF_MONTH, currentDay1+2);
        while (cal1.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY || 
                cal1.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) {
           cal1.add(Calendar.DATE, 1);
       }
        Date DateDate1 = cal1.getTime();
        SimpleDateFormat postFormater1 = new SimpleDateFormat("dd-M-yyyy"); 

        String newDateStr1 = postFormater1.format(DateDate1); 
        // Set URL
        mWebview .loadUrl("http://divers.ommelandercollege.nl/webportalen/dagrooster.php?datum="+newDateStr1);
        setContentView(mWebview );
        break;
    // If Help is pressed
    case R.id.action_settings:
        // Toast message
        Toast.makeText(this, "Laden van de Help pagina.",
        Toast.LENGTH_SHORT).show();
        // Load Help
        mWebview .loadUrl("https://dl.dropboxusercontent.com/u/53488707/RoosterwijzigingenApp/index.html");
        setContentView(mWebview );
        break;
    // If Vandaag is pressed
    case R.id.menu_back:
        // Toast message
        Toast.makeText(this, "Vandaag",
        Toast.LENGTH_SHORT).show();
        // Load Help
        mWebview.loadUrl("http://divers.ommelandercollege.nl/webportalen/dagrooster.php");
        setContentView(mWebview);
        break;
    }
    return super.onOptionsItemSelected(item);
}

LogCat

06-25 16:04:12.495: E/AndroidRuntime(16692): FATAL EXCEPTION: main
06-25 16:04:12.495: E/AndroidRuntime(16692): java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.view.ViewGroup.addViewInner(ViewGroup.java:3378)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.view.ViewGroup.addView(ViewGroup.java:3249)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.view.ViewGroup.addView(ViewGroup.java:3225)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:275)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:265)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.app.Activity.setContentView(Activity.java:1887)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at org.flikkema.robin.dagrooster.MainActivity.onOptionsItemSelected(MainActivity.java:138)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.app.Activity.onMenuItemSelected(Activity.java:2534)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:958)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:514)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:99)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.view.View.performClick(View.java:4084)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.view.View$PerformClick.run(View.java:16966)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.os.Handler.handleCallback(Handler.java:615)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.os.Handler.dispatchMessage(Handler.java:92)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.os.Looper.loop(Looper.java:137)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at android.app.ActivityThread.main(ActivityThread.java:4745)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at java.lang.reflect.Method.invokeNative(Native Method)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at     java.lang.reflect.Method.invoke(Method.java:511)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-25 16:04:12.495: E/AndroidRuntime(16692):    at dalvik.system.NativeStart.main(Native Method)

LogCat谈到了removeview（）

Answer 1

setContentView()实际上应该只在onCreate()被调用一次。

否则，每次调用它时，都需要再次填充所有视图引用。 不要在onOptionsItemSelected再次调用它