Question

我想在NumberPicker内使用Tabhost，Dialog可通过NumberPicker访问。但是如何定义NumberPicker np = (NumberPicker) d.findViewById(R.id.numberPicker);？目前我正在这样做：

    String[] array = {"1","2","3"};

    public void dialog(){
    final Dialog d = new Dialog(this);
    d.setTitle("Dialog");
    d.setContentView(R.layout.dialog);
    d.setCanceledOnTouchOutside(false);

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

    tabHost.setup(getLocalActivityManager());
    tabHost.setup();

    TabHost.TabSpec tab1 = tabHost.newTabSpec("Favs");
    TabHost.TabSpec tab2 = tabHost.newTabSpec("All");

    tab1.setIndicator("Favs");
    tab1.setContent(R.id.tab1act);

    tab2.setIndicator("All");
    tab2.setContent(R.id.tab2act);

    tabHost.addTab(tab1);
    tabHost.addTab(tab2);
    tabHost.setCurrentTab(0);

    NumberPicker np = (NumberPicker) d.findViewById(R.id.numberPicker);
    np.setMaxValue(array.length);   //NullPointerException here
    np.setMinValue(1);
    np.setWrapSelectorWheel(true);
    np.setOnValueChangedListener(this);
    np.setDisplayedValues(array);
    np.setDescendantFocusability(NumberPicker.FOCUS_BLOCK_DESCENDANTS);

    d.show();
}

但这不起作用。我在下面的行中得到一个NullPointerException（参见下面的代码）。

有什么建议吗？或者怎么做对了？

1-30 17:18:27.579  32038-32038/com.app.main E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
        at com.app.main.Main.dialog(Main.java:283)
        at com.app.main.Main$1.onClick(Main.java:142)
        at android.view.View.performClick(View.java:4475)
        at android.view.View$PerformClick.run(View.java:18786)
        at android.os.Handler.handleCallback(Handler.java:730)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:176)
        at android.app.ActivityThread.main(ActivityThread.java:5419)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
        at dalvik.system.NativeStart.main(Native Method)

logcat的：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">

<TabHost
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/tabHost">

    <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"></TabWidget>

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

            <include
                android:id="@+id/tab1act"
                android:layout_width="fill_parent"
                android:layout_height="match_parent"
                layout="@layout/tab1act" >
            </include>

            <include
                android:id="@+id/tab2act"
                android:layout_width="fill_parent"
                android:layout_height="match_parent"
                layout="@layout/tab1act" >
            </include>

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

Dialog.xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">

<NumberPicker
    android:id="@+id/numberPicker"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

</LinearLayout>

Tab1act.xml：

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">

<NumberPicker
    android:id="@+id/numberPicker"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

</LinearLayout>

Tab2act.xml：

{{1}}

如何在Dialog中的Tabhost中声明Numberpicker？

0 个答案: