Android的：如何让一个片段的意见 [英] Android: how to get the views of a Fragment

问题描述

在一个类我加入一个片段编程。

In a class i am adding a Fragment programatically.

该片段包含一个按钮，我想有一个onClick实现。

This Fragment contains a Button, which i want to have an onClick implementation.

下面是类我有：

public class ShareProduct extends SherlockFragmentActivity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.share_product);

        FragmentManager fragmentManager = getSupportFragmentManager();
        final FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();

        ProductFragment1 fragment = new ProductFragment1();
        fragmentTransaction.add(R.id.share_product_parent, fragment);
        fragmentTransaction.commit();

        Button done_button = (Button) fragment.getView().findViewById(
                R.id.done_product_1);
        done_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {

                ProductFragment2 fragment = new ProductFragment2();
                fragmentTransaction
                        .replace(R.id.share_product_parent, fragment);
                fragmentTransaction.commit();
            }
        });
    }
}

和我ProductFragment1类是：

and my ProductFragment1 class is:

public class ProductFragment1 extends SherlockFragment {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater
                .inflate(R.layout.share_product_1, container, false);
        return view;
    }
}

和我的主类使用的布局是：

and the layout my main class uses is:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/share_product_parent"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:gravity="right|center_vertical"
    android:orientation="horizontal" >

</RelativeLayout>

和我ProductFragment1使用的布局是：

and the layout my ProductFragment1 uses is:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tv1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="25dp" />

    <EditText
        android:id="@+id/et1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv1"
        android:textSize="25dp" />

    <Button
        android:id="@+id/done_product_1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/et1"
        android:text="Done" />

</RelativeLayout>

的问题是：

我得到一个NullPointerException异常，在此行中我的​​主类：

I am getting a NullPointerException at this line in my main class:

Button done_button = (Button) fragment.getView().findViewById(R.id.done_product_1);
done_button.setOnClickListener ....

当我搜索什么 getView（）上一个片段的回报。我发现，它返回从 onCreateView（）的观点;

when i searched for what getView() on a fragment returns. I found out that it returns the view from onCreateView();

我检查没有返回null。

I checked it doesn't return null.

感谢您

推荐答案

您是在错误的轨道在这里。你得到的 NPE ，因为片段的意见是尚未创建。 片段也有，就像活动生命周期。

You are on the wrong track here. You get the NPE because the Fragments views is not created yet. Fragments also have a lifecycle just like Activities.

你应该做的是分配 OnClickListener 里面的片段 onViewCreated（） 方法。从那里...你应该创建一个回调，并通知您的主机活动事件。

What you should be doing is assigning the OnClickListener inside your Fragments onViewCreated() method. And from there... you should create a callback and notify your hosting Activity of the event.

这篇关于Android的：如何让一个片段的意见的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！