如何实现允许用户在应用程序中添加和删除选项卡的命令？

Question

我正在尝试制作一个顶部带有标签的应用程序，这些标签也链接一个网站，例如在 safari 或 firefox 中使用标签的计算机。我想要做的是实现一个添加和删除类，它允许用户在需要时删除一个选项卡并添加另一个链接到不同网站的选项卡。任何帮助将不胜感激。

这是主要的 java 文件。

public class UniversityofColorado extends TabActivity {


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    TabHost host=getTabHost();

    host.addTab(host.newTabSpec("one")
            .setIndicator("Google")
            .setContent(new Intent(this, Hello.class)));

    host.addTab(host.newTabSpec("two")
                    .setIndicator("Colorado Main Site")
                    .setContent(new Intent(this, ColoradoMainSiteBrowser.class)));

    host.addTab(host.newTabSpec("three")
                    .setIndicator("CULearn")
                    .setContent(new Intent(this, CULearnBrowser.class)));

    host.addTab(host.newTabSpec("four")
            .setIndicator("CULink")
            .setContent(new Intent(this, CULinkBrowser.class)));

    host.addTab(host.newTabSpec("five")
            .setIndicator("MyCUInfo")
            .setContent(new Intent(this, MyCUInfoBrowser.class)));

    host.addTab(host.newTabSpec("six")
            .setIndicator("Campus Map")
            .setContent(new Intent(this, CampusBrowser.class)));

    host.addTab(host.newTabSpec("Seven")
            .setIndicator("Notes")
            .setContent(new Intent(this, Notepadv3.class)));
}   




    // Inflates menu when "menu Key" is pressed
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu, menu);
        return true;
    }
}

这是主要 java 文件使用的 java 文件之一：

public class ColoradoMainSiteBrowser extends Activity {

WebView webview;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
webview = (WebView) findViewById(R.id.webview);
webview.setWebViewClient(new HelloWebViewClient());
webview.getSettings().setJavaScriptEnabled(true);
webview.loadUrl("http://colorado.edu/");
}
private class HelloWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) {
webview.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
}

当添加新标签时，如何实现添加和删除按钮以具有相同的格式。

Answer 1

为了达到预期的效果，您可能需要为每个选项卡方法删除一个活动。

相反，您将创建一个“默认”视图，您可以将其用于所有接受 URL 作为参数的网站。

然后，不是为每个选项卡“意图”一个新活动，而是将该视图膨胀到新选项卡，将 URL 作为参数传递。

动态地创建和删除选项卡会很容易。一个简单的膨胀/移除视图的按钮就足够了。

---

XML

res/layout/main.xml

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="5dp">
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:padding="5dp" />
    </LinearLayout>    
</TabHost>

res/layout/tab.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
>
<TextView
android:id="@+id/url_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="HELLO TAB!"
>
</TextView>
</LinearLayout>

res/menu/menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:enabled="true" android:visible="true" android:icon="@android:drawable/ic_menu_add" android:title="Add Website" android:titleCondensed="add" android:id="@+id/add"></item>
<item android:titleCondensed="Delete" android:enabled="true" android:visible="true" android:icon="@android:drawable/ic_menu_delete" android:id="@+id/delete" android:title="Delete Website"></item>
</menu>

JAVA 代码

main.java

import android.app.TabActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.TabHost;
import android.widget.TextView;


public class Main extends TabActivity implements TabHost.TabContentFactory {


    TabHost tabHost;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        this.tabHost = getTabHost();  // The activity TabHost

        tabHost.addTab(tabHost.newTabSpec("http://www.google.com/").setIndicator("Google").setContent(this));
        tabHost.addTab(tabHost.newTabSpec("http://www.stackoverflow.com/").setIndicator("StackOverflow").setContent(this)); 
    }

    public View createTabContent(String tag) {

        // Inflation per se.
        // we don't return anything yet so we can work with this view
        View tab = View.inflate(this, R.layout.tab, null);

        // Here we work with the view
        // in this case we set the textview to match our tag
        // its a good way to parse arguments to the new tab
        TextView tv = (TextView) tab.findViewById(R.id.url_tv);
        tv.setText(tag);

        //After work we can return view
        return tab;  
    }


    private void addMethod(String webSiteURL, String webSiteName) {

        // Find a way that suits you to pass arguments to here

        tabHost.addTab(tabHost.newTabSpec(webSiteURL).setIndicator(webSiteName).setContent(this));

    }

    private void deleteMethod() {

        // Create a way to decide which tab to delete.
        // for instance, FindViewByTag is a method of ViewGroup and works
        // then call the parent of the view with
        // ViewGroup parent = (ViewGroup) viewToDelete.getParent();
        // finally use oarent.removeView(viewToDelete);

    }

    // Inflates menu when "menu Key" is pressed
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu, menu);
        return true;
    }


    // This method is called once the menu is selected
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {


        switch (item.getItemId()) {

            case R.id.add:

                // These variable is created artificially so that something is passed to our addMethod
                // You should find a way to pass these argument to our method
                // can be a dialog screen, or getting the URL from somewhere
                // its your call
                String webSiteURL = "http://www.evonytools.org/";
                String webSiteName = "Tivie's Tools";

                addMethod(webSiteURL, webSiteName);

            case R.id.delete:

                deleteMethod();

                break;
        }
        return true;
    }  
}