与code创建布局 [英] Creating layout with code

问题描述

我有问题，创建具有code布局。我只是想补充我的线性布局的按钮对象，但它不会产生任何按钮。

下面是我的onCreate方法：

 保护无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.activity_main）;    的LinearLayout布局=（的LinearLayout）findViewById（R.id.layout）;    Button按钮=新按钮（本）;
    button.setText（R.string.click_me）;    layout.addView（按钮）;    如果（savedInstanceState == NULL）{
        getFragmentManager（）调用BeginTransaction（）
                。新增（R.id.container，新PlaceholderFragment（））
                。承诺（）;
    }
}
 

我fragment_main.xml：

 ＆LT; LinearLayout中的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
机器人：layout_width =FILL_PARENT
机器人：layout_height =FILL_PARENT
机器人：layout_margin =10dp
机器人：ID =@ + ID /布局
机器人：方向=垂直＆GT;
 

***更新*** 1

因此​​，对布局添加对象的时候，当你有一个片段XML它必须在片段类。感谢@Fllo指出了这一点。有没有想到这样的。 :(

下面是我更新code在上添加PlaceHolderFragment类的按钮。

 公共静态类PlaceholderFragment扩展片段{    公共PlaceholderFragment（）{
    }    @覆盖
    公共查看onCreateView（LayoutInflater充气器，容器的ViewGroup，
            捆绑savedInstanceState）{
        查看rootView = inflater.inflate（R.layout.fragment_main，集装箱，FALSE）;
        的LinearLayout布局=（的LinearLayout）rootView.findViewById（R.id.layout）;
        Button按钮=新按钮（getActivity（））;
        button.setText（R.string.click_me）;
        layout.addView（按钮）;
        返回rootView;
    }
}
 

解决方案

看来你建立你的看法里面的 fragment_main.xml 而非 activity_main.xml中。

在第一个的创建一个新的Andr​​oid项目，你有自动创建和打开这些文件：

然后，当你开始，你添加视图的（例如：一个TextView）的内部 fragment_main.xml 文件，而你试图做一个基本事件与活动里面这个观点使用这种布局：

 的setContentView（R.layout.activity_main）; //使用activity_main.xml中的文件
 

您不能运行你的应用程序或有时你只有一个白色的屏幕，因为你尝试调用/显示器的意见是入错了布局。

  

解决方案：移动你所有的东西onCreateView方法进入片段类中。打电话的意见和做一些相关的片段，而不是父活动。

---

把你所有的东西，你的 onCreateView 方法内到您的 PlaceholderFragment 类，如下所示：

  @覆盖
公共查看onCreateView（LayoutInflater充气器，容器的ViewGroup，
        捆绑savedInstanceState）{
    查看rootView = inflater.inflate（R.layout.fragment_main，集装箱，FALSE）;    //不要忘记您的视图连接到布局
    的LinearLayout布局=（的LinearLayout）rootView.findViewById（R.id.layout）;
    //连接上下文
    Button按钮=新按钮（getActivity（））;
    //添加布局PARAMS
    button.setLayoutParams（新LinearLayout.LayoutParams（LinearLayout.LayoutParams.WRAP_CONTENT，LinearLayout.LayoutParams.WRAP_CONTENT））;
    //设置文本
    button.setText（R.string.click_me）;
    //添加视图
    layout.addView（按钮）;    返回rootView;
}
 

I have problem with creating layout with code. I'm just trying to add a button object on my linear layout but it doesn't create any button.

Here's my onCreate method:

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

    LinearLayout layout = (LinearLayout) findViewById(R.id.layout);

    Button button = new Button(this);
    button.setText(R.string.click_me);

    layout.addView(button);

    if (savedInstanceState == null) {
        getFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment())
                .commit();
    }
}

My fragment_main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_margin="10dp"
android:id="@+id/layout"
android:orientation="vertical" >

***update 1***

So when adding objects on layout when you have a fragment xml it must be on the fragment class. Thanks to @Fllo for pointing that out. Haven't thought of that way. :(

Here's my updated code in adding the button on PlaceHolderFragment class.

public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);


        LinearLayout layout = (LinearLayout) rootView.findViewById(R.id.layout);
        Button button = new Button(getActivity());
        button.setText(R.string.click_me);
        layout.addView(button);
        return rootView;
    }
}

解决方案

It seems you built your views inside fragment_main.xml and not activity_main.xml.

When you first create a new android project, you have these files which are automatically created and opened:

Then, when you begin, you add views (e.g: a TextView) inside fragment_main.xml file whereas you tried to do a basically event with this view inside your Activity which uses this layout:

setContentView(R.layout.activity_main); // using the activity_main.xml file

You cannot run your app or sometimes you have only a white screen, because the views that you tried to call/display are into the wrong layout..

Solution: Move all your stuff inside onCreateView method into the Fragment class. Call views and do something in the related fragment and not the parent activity.

---

Move all your stuff inside your onCreateView method into your PlaceholderFragment class, as follows:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_main, container, false);  

    // Don't forget to attach your view to the layout
    LinearLayout layout = (LinearLayout) rootView.findViewById(R.id.layout);
    // Attach the context
    Button button = new Button(getActivity());
    // Add the layout params
    button.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    // Set the text
    button.setText(R.string.click_me);
    // Add the view
    layout.addView(button);  

    return rootView;
}

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