android : tabhost 不呈现选项卡

Question

我有一个简单的activity

public class MainActivity extends Activity {
    private TabHost tabHost;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        tabHost = (TabHost)findViewById(R.id.tabHost);
        tabHost.setup();
        tabHost.newTabSpec("a");
        tabHost.newTabSpec("b");
        tabHost.newTabSpec("c");
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是 xml 的视图定义

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="activities.MainActivity"
    android:visibility="visible">

    <TabHost
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tabHost"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true">

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical">

            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:visibility="visible"
                android:background="#ff0007ff"></TabWidget>

            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent">

                <LinearLayout
                    android:id="@+id/tab1"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:orientation="vertical"
                    android:visibility="visible"
                    android:background="#ff122dff"></LinearLayout>

                <LinearLayout
                    android:id="@+id/tab2"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:orientation="vertical"></LinearLayout>

                <LinearLayout
                    android:id="@+id/tab3"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:orientation="vertical"></LinearLayout>
            </FrameLayout>
        </LinearLayout>
    </TabHost>

</RelativeLayout>

我知道 tabhost 的视图有空白内容，但我希望在这个 activity 启动时至少呈现选项卡的视图

但是我看到此 activity 的空白屏幕，我错过了什么？

Answer 1

您必须将每个选项卡项添加到选项卡小部件，如下所示：

tabHost = (TabHost)findViewById(R.id.tabHost);
tabHost.setup();

TabHost.TabSpec tab1 = tabs.newTabSpec("tab1");
tab1.setContent(R.id.tab1);
tab1.setIndicator("Tab 1");
tabHost.addTab(tab1);

Answer 2

选项卡是使用片段实现的。在 xml 中，您需要使用 android.support.v4.app.FragmentTabHost class 而不是 TabHost。在 java 中，您需要扩展 FragmentActivity，还需要手动在 FragmentTabHost 中添加选项卡。给出了完整的例子 here.

android : tabhost 不呈现选项卡

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