LayoutInflater 类的使用

转　　http://yxwang0615.iteye.com/blog/1711147

一个Activity里如果直接用findViewById(),对应的是setConentView()的那个layout里的组件，因此如果你的

Activity里如果用到别的layout，你就必须用inflate()先将对话框上的layout找出来,然后再用这个layout对

象去找到它上面的组件，

Java代码

1. public View inflate(Context context, int Resourece,ViewGroup root)
2. 作用：填充一个新的视图层次结构从指定的XML资源文件中
3. context : The Context object for your activity or application
4. reSource：View的layout的ID
5. root： 生成的层次结构的根视图
6. return 填充的层次结构的根视图。如果参数root提供了，那么root就是根视图；否则填充的XML文件的根就是根视图。

public View inflate(Context context, int Resourece,ViewGroup root)
  作用：填充一个新的视图层次结构从指定的XML资源文件中
  context : The Context object for your activity or application
  reSource：View的layout的ID
  root： 生成的层次结构的根视图
  return 填充的层次结构的根视图。如果参数root提供了，那么root就是根视图；否则填充的XML文件的根就是根视图。

View view = View.inflate(this, R.layout.dialog_layout, null);

TextView dialogTV = (TextView) view.findViewById(R.id.dialog_tv);

dialogTV.setText("abcd");

setContentView()一旦调用, layout就会立刻显示UI；而inflate只会把Layout形成一个以view类实现成的对象，

有需要时再用setContentView(view)显示出来。一般在activity中通过setContentView()将界面显示出来，

然后才能使用findViewById()是找xml布局文件下的具体widget控件(如Button、TextView等)

但是如果在非activity中如何对控件布局设置操作了，这就需要LayoutInflater动态加载。

LayoutInflater是用来找res/layout/下的xml布局文件，并且实例化。

Java代码

1. LayoutInflater inflater = LayoutInflater.from(this);
2. View view=inflater.inflate(R.layout.ID, null);
3. //或者干脆并成一句：
4. View view=LayoutInflater.from(this).inflate(R.layout.ID, null);

LayoutInflater inflater = LayoutInflater.from(this);
View view=inflater.inflate(R.layout.ID, null);
//或者干脆并成一句：
View view=LayoutInflater.from(this).inflate(R.layout.ID, null); 

或者：

Java代码

1. LayoutInflater inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
2. View view=inflater.inflate(R.layout.ID, null);

LayoutInflater inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
View view=inflater.inflate(R.layout.ID, null); 

android.view.View类中也有一个inflater方法：

Java代码

1. public static View inflate (Context context, int resource, ViewGroup root)
2. Inflate a view from an XML resource. This convenience method wraps the LayoutInflater class, which provides a full range of options for view inflation.
3. Parameters
4. context The Context object for your activity or application.
5. resource The resource ID to inflate
6. root A view group that will be the parent. Used to properly inflate the layout_* parameters.

public static View inflate (Context context, int resource, ViewGroup root)

Inflate a view from an XML resource. This convenience method wraps the LayoutInflater class, which provides a full range of options for view inflation.
Parameters

context	The Context object for your activity or application.
resource	The resource ID to inflate
root	A view group that will be the parent. Used to properly inflate the layout_* parameters.

该方法和LayoutInflater中的inflater方法区别不明，查api也没看明白：

Java代码

1. public View inflate (int resource, ViewGroup root)
2. Inflate a new view hierarchy from the specified xml resource. Throws InflateException if there is an error.
3. Parameters
4. resource ID for an XML layout resource to load (e.g., R.layout.main_page)
5. root Optional view to be the parent of the generated hierarchy.
6. Returns
7. The root View of the inflated hierarchy. If root was supplied, this is the root View; otherwise it is the root of the inflated XML file.

public View inflate (int resource, ViewGroup root)
Inflate a new view hierarchy from the specified xml resource. Throws InflateException if there is an error.

Parameters

resource	ID for an XML layout resource to load (e.g., R.layout.main_page)
root	Optional view to be the parent of the generated hierarchy.

Returns
The root View of the inflated hierarchy. If root was supplied, this is the root View; otherwise it is the root of the inflated XML file.

一般在adapter的getview方法中使用View.inflate的比较多，最近在研究自定义下拉刷新listview的时候，使用了View.inflate一直报如下错误：

Java代码

1. mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
2. shView = (RelativeLayout) mInflater.inflate(R.layout.pull_to_refresh_header, this, false);
3. //mRefreshView = (RelativeLayout)View.inflate(context, R.layout.pull_to_refresh_header, null);

        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
		mRefreshView = (RelativeLayout) mInflater.inflate(R.layout.pull_to_refresh_header, this, false);
        //mRefreshView = (RelativeLayout)View.inflate(context, R.layout.pull_to_refresh_header, null);

Xml代码

1. android.view.InflateException: Binary XML file line #10: Error inflating class com.markupartist.android.widget.PullToRefreshListView

android.view.InflateException: Binary XML file line #10: Error inflating class com.markupartist.android.widget.PullToRefreshListView

而使用 LayoutInflater 就没事，原因翻阅很多资料都没弄明白，看样子定义控件的inflate还是使用

LayoutInflater 吧！