Java 如何在对话框中的Tabhost中声明Numberpicker？_Java_Android_Nullpointerexception_Dialog_Android Tabhost

Java 如何在对话框中的Tabhost中声明Numberpicker？

java android

Java 如何在对话框中的Tabhost中声明Numberpicker？,java,android,nullpointerexception,dialog,android-tabhost,Java,Android,Nullpointerexception,Dialog,Android Tabhost,我想在Tabhost中使用NumberPicker，它可以通过对话框访问。但是如何定义NumberPicker？目前我正在这样做： NumberPicker np = (NumberPicker) d.findViewById(R.id.numberPicker); 但这是行不通的。我在下面的一行中得到一个NullPointerException（参见下面的代码）有什么建议吗？或者怎样做才是正确的 String[] array = {"1","2","3"}; public

我想在

Tabhost

中使用

NumberPicker

，它可以通过

对话框访问。但是如何定义NumberPicker
？目前我正在这样做：
NumberPicker np = (NumberPicker) d.findViewById(R.id.numberPicker);

但这是行不通的。我在下面的一行中得到一个NullPointerException（参见下面的代码）
有什么建议吗？或者怎样做才是正确的
    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();
}

Logcat:
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)

<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>

<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>

    <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>

Dialog.xml:
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)

<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>

<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>

    <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:
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)

<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>

<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>

    <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:
1-30 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)

<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>

<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>

    <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>


你初始化了你的数组吗？是的，让我补充一下..请发布dialog.xml文件，可能那里没有numberPicker，因此d.findViewById（R.id.numberPicker）返回nulldialog.xml
没有numberPicker
但它包含到其他.xml
有numberPicker的文件尝试以下操作：View tab=d.findviewbyd（R.id.tab1act）；NumberPicker np=（NumberPicker）tab.findViewById（R.id.NumberPicker）；并查看tab是null还是np。请注意，您将包含相同的布局（tab1act.xml）两次（调用相同的xml文件）。