android - 尝试动态生成选项卡及其视图

Question

更新：

编译错误已解决，我根据我所遵循的示例发现了一些我没有正确完成的事情并更正了它们。但是，当我尝试运行代码时，出现以下错误。当我浏览代码时，我注意到 NewTab.setContent 中的 createTabContent 没有执行，因为我在那里的断点从未被触发。

01-12 10:11:21.285: E/AndroidRuntime(14528): FATAL EXCEPTION: main
01-12 10:11:21.285: E/AndroidRuntime(14528): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jackman.universalav/com.jackman.universalav.MainActivity}: android.content.res.Resources$NotFoundException: Resource ID #0x0
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread.access$600(ActivityThread.java:140)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.os.Handler.dispatchMessage(Handler.java:99)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.os.Looper.loop(Looper.java:137)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread.main(ActivityThread.java:4898)
01-12 10:11:21.285: E/AndroidRuntime(14528): at java.lang.reflect.Method.invokeNative(Native Method)
01-12 10:11:21.285: E/AndroidRuntime(14528): at java.lang.reflect.Method.invoke(Method.java:511)
01-12 10:11:21.285: E/AndroidRuntime(14528): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
01-12 10:11:21.285: E/AndroidRuntime(14528): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
01-12 10:11:21.285: E/AndroidRuntime(14528): at dalvik.system.NativeStart.main(Native Method)
01-12 10:11:21.285: E/AndroidRuntime(14528): Caused by: android.content.res.Resources$NotFoundException: Resource ID #0x0
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.content.res.Resources.getValue(Resources.java:1026)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.content.res.Resources.loadXmlResourceParser(Resources.java:2131)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.content.res.Resources.getLayout(Resources.java:865)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.widget.TabHost$LabelIndicatorStrategy.createIndicatorView(TabHost.java:554)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.widget.TabHost.addTab(TabHost.java:234)
01-12 10:11:21.285: E/AndroidRuntime(14528): at com.jackman.universalav.MainActivity.onCreate(MainActivity.java:71)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.Activity.performCreate(Activity.java:5191)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
01-12 10:11:21.285: E/AndroidRuntime(14528): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
01-12 10:11:21.285: E/AndroidRuntime(14528): ... 11 more

更新后的代码是：

public class MainActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Create the tab host that contains the tab widget that contains the tabs
        TabHost Tabs = new TabHost(this);
        Tabs.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        //Create the tab widget  container
        TabWidget TabWidget = new TabWidget(this);
        TabWidget.setId(android.R.id.tabs);
        Tabs.addView(TabWidget, new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        //the tab host needs a frame layout for the views associated with each visible tab
        FrameLayout frameLayout = new FrameLayout(this);
        frameLayout.setId(android.R.id.tabcontent);
        frameLayout.setPadding(0, 65, 0, 0);
        Tabs.addView(frameLayout, new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        Tabs.setup();
        //Create the tabs
        DatabaseHelper dbHelper = new DatabaseHelper(this);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        String dbQuery = "SELECT * FROM " + dbHelper.System_Table + " AS s JOIN " + dbHelper.Devices_Table + " AS d ON s." + dbHelper.Attribute_Device_ID +
            " = d." + dbHelper.Attribute_Device_ID + ";";
        Cursor c = db.rawQuery(dbQuery, null);
        if (c.getCount() > 0)
        {
            while (c.moveToNext())
            {
                  int iColumnDeviceType = c.getColumnIndex(dbHelper.Attribute_Device_Type);
                  int iColumnDeviceName = c.getColumnIndex(dbHelper.Attribute_Device_Name);
                  final String DeviceType = c.getString(iColumnDeviceType);
                  String DeviceName = c.getString(iColumnDeviceName);
                  String DeviceNameLabel = DeviceName.replaceAll(" ", "");
                  TabSpec NewTab = Tabs.newTabSpec("tab" + DeviceNameLabel);
                  NewTab.setIndicator(DeviceNameLabel);
                  NewTab.setContent(new TabHost.TabContentFactory()
                  {
                    public View createTabContent(String tag)
                    {
                        LinearLayout ll = new LinearLayout(MainActivity.this);
                        LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
                        ll.setLayoutParams(params);
                        ll.setOrientation(LinearLayout.VERTICAL);
                        if (DeviceType == "Receiver")
                        {

                        }
                        else if (DeviceType == "Video Player")
                        {

                        }
                        return ll;
                     }
                   });
                   Tabs.addTab(NewTab);
             }
        }
    }
}

结束更新

下面的原始问题：

我还没有到这个例程完成的地步。

我试图遵循此链接中的代码示例。http://www.pocketmagic.net/2010/01/android-dynamic-tab-control/

但是，当我尝试为正在创建的选项卡创建线性布局时，编译器吓坏了我。我不确定它为什么会抛出错误。就像我前一行做的对象不存在一样。

返回的错误是：

Multiple markers at this line
- Syntax error on token(s), misplaced construct(s)
- Syntax error on token "params", VariableDeclaratorId expected after this token

无论如何，代码如下。谁能看到我做错了什么？

//Create the tab host that contains the tab widget that contains the tabs
TabHost Tabs = new TabHost(this);
Tabs.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
//Create the tab widget  container
TabWidget TabWidget = new TabWidget(this);
TabWidget.setId(android.R.id.tabs);
Tabs.addView(TabWidget, new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
Tabs.setup();
//Create the tabs
DatabaseHelper dbHelper = new DatabaseHelper(this);
SQLiteDatabase db = dbHelper.getWritableDatabase();
String dbQuery = "SELECT * FROM " + dbHelper.System_Table + " AS s JOIN " +
    dbHelper.Devices_Table + " AS d ON s." + dbHelper.Attribute_Device_ID +
    " = d." + dbHelper.Attribute_Device_ID + ";";
Cursor c = db.rawQuery(dbQuery, null);
if (c.getCount() > 0)
{
    while (c.moveToNext())
    {
        int iColumnDeviceType = c.getColumnIndex(dbHelper.Attribute_Device_Type);
        int iColumnDeviceName = c.getColumnIndex(dbHelper.Attribute_Device_Name);
        final String DeviceType = c.getString(iColumnDeviceType);
        String DeviceName = c.getString(iColumnDeviceName);
        String DeviceNameLabel = DeviceName.replaceAll(" ", "");
        TabSpec NewTab = Tabs.newTabSpec("tab" + DeviceNameLabel);
        NewTab.setIndicator(DeviceName);
        NewTab.setContent(new TabHost.TabContentFactory()
        {
            LinearLayout ll = new LinearLayout(MainActivity.this);
            LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
            ll.setLayoutParams(params); //this line has both of the errors
            public View createTabContent(String tag)
            {
                    if (DeviceType == "Receiver")
                    {

                    }
                    else if (DeviceType == "Video Player")
                    {

                    }
                    return null; //place holder until I finish the routine
                }
            });
            Tabs.addTab(NewTab);
        }
    }

Answer 1

经过反复试验和谷歌搜索大量示例后，我发现了这个问题。

首先，我放弃了尝试通过 java 而不是 xml 为活动创建选项卡小部件和框架布局。

在我的活动布局 xml 文件中，我添加了一个选项卡控件，并在 xml 视图中删除了选项卡，使 xml 代码看起来像这样。

<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"
tools:context=".MainActivity" >

    <TabHost
    android:id="@android:id/tabhost"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true" >

        <LinearLayout
        android:id="@+id/MainLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >
        </TabWidget>

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


            </FrameLayout>
        </LinearLayout>
    </TabHost>
</RelativeLayout>

然后在活动的 java 文件中，我将 oncreate 例程更新为这个。

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//Create the tabs
TabHost Tabs = (TabHost) findViewById(android.R.id.tabhost);
Tabs.setup();
DatabaseHelper dbHelper = new DatabaseHelper(this);
SQLiteDatabase db = dbHelper.getWritableDatabase();
String dbQuery = "SELECT * FROM " + dbHelper.System_Table + " AS s JOIN " +
    dbHelper.Devices_Table + " AS d ON s." + dbHelper.Attribute_Device_ID +
    " = d." + dbHelper.Attribute_Device_ID + ";";
Cursor c = db.rawQuery(dbQuery, null);
int Count = 0;
if (c.getCount() > 0)
{
    while (c.moveToNext())
    {
        Count = Count + 1;
        int iColumnDeviceType = c.getColumnIndex(dbHelper.Attribute_Device_Type);
        int iColumnDeviceName = c.getColumnIndex(dbHelper.Attribute_Device_Name);
        final String DeviceType = c.getString(iColumnDeviceType);
        final String DeviceName = c.getString(iColumnDeviceName);
        final String DeviceNameLabel = DeviceName.replaceAll(" ", "");
        Log.d("Creating Tab", "TabSpec: tab" + DeviceNameLabel);
        Log.d("Creating Tab", "Indicator: " + DeviceName);
        final TabSpec NewTab = Tabs.newTabSpec("tab" + DeviceNameLabel);
        NewTab.setIndicator(DeviceName);
        NewTab.setContent(new TabHost.TabContentFactory()
        {
            @Override
            public View createTabContent(String tag)
            {
                LinearLayout ll = new LinearLayout(MainActivity.this);
                LayoutParams params = new LinearLayout.LayoutParams(
                    LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
                ll.setLayoutParams(params);
                ll.setOrientation(LinearLayout.VERTICAL);
                if (DeviceType.equals("Receiver"))
                {
                    final Button btnVolumeUp = new Button(MainActivity.this);
                    btnVolumeUp.setText("Volume Up");
                    btnVolumeUp.setLayoutParams(new LayoutParams(
                        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
                    btnVolumeUp.setGravity(Gravity.LEFT);
                    ll.addView(btnVolumeUp);
                }
                else if (DeviceType.equals("Video Player"))
                {
                    final Button btnPlay = new Button(MainActivity.this);
                    btnPlay.setText("Play");
                    btnPlay.setLayoutParams(new LayoutParams(
                        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
                    btnPlay.setGravity(Gravity.LEFT);
                    ll.addView(btnPlay);
                }
                return ll;
            }
        });

        Tabs.addTab(NewTab);

    }
}