Question

我想在我的应用中试用WizarDroid库。但由于我对充气器相当缺乏经验，因此我坚持这个错误几个小时。

我在尝试 findViewById 时遇到 NullPointerException ，我无法弄清楚原因。

public class WizardStep1 extends WizardStep {

    //Wire the layout to the step
    public WizardStep1() {
    }

    //Set your layout here
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.wizard, container, false);
        TextView tv = (TextView) v.findViewById(R.id.wizard_textView); // tv = null
        tv.setText("This is an example of Step 1 in the wizard. Press the Next " + // NullPointerException gets thrown here
                "button to proceed to the next step. Hit the back button to go back to the calling activity.");

        return v;
    }
}

所以 TextView tv 由于某种原因为空。我无法理解这一点，因为我在XML R.layout.wizard

中明确定义了它

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

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/wizard_textView"
        android:layout_marginTop="10dp"
        android:textSize="20dp"
        android:text="gtsets" />
</LinearLayout>

此代码也来自他们的文档，因此它让我更加困惑：/

编辑：这是wizardStartup类：

public class wizardStartup extends BasicWizardLayout {

    /**
     * Note that initially BasicWizardLayout inherits from {@link android.support.v4.app.Fragment} and therefore you must have an empty constructor
     */
    public wizardStartup() {
        super();
    }

    //You must override this method and create a wizard flow by
    //using WizardFlow.Builder as shown in this example
    @Override
    public WizardFlow onSetup() {
        /* Optionally, you can set different labels for the control buttons
        setNextButtonLabel("Advance");
        setBackButtonLabel("Return");
        setFinishButtonLabel("Finalize"); */

        return new WizardFlow.Builder()
                .addStep(WizardStep1.class)           //Add your steps in the order you want them
                .addStep(WizardStep2.class)           //to appear and eventually call create()
                .create();                              //to create the wizard flow.
    }
}

LogCat：

07-15 17：58：05.491 10299-10299 / ba.imasoft.dfms.app E / AndroidRuntime：致命异议：主要显示java.lang.NullPointerException at ba.imasoft.dfms.app.wizards.steps.WizardStep1.onCreateView（WizardStep1.java:28）

第28行是'tv.setText（“This'..

如果我注释掉包含tv变量的行它可以工作但不是它应该的方式..我需要编辑每个步骤的视图。

tv = null证明......

watches

Answer 1

这个问题很奇怪......

无论如何，我所做的就是将 wizard.xml 更改为 wizard_step.xml ，认为它正在使用 wizard.xml 作为库中的其他内容HMM ..

有效。

如何从片段中扩展视图？

1 个答案: