android中LayoutInflater的使用

Inflater英文意思是膨胀，在android中应该是扩展的意思吧。
LayoutInflater的作用类似于 findViewById(),不同点是LayoutInflater是用来找layout文件夹下的xml布局文件，并且实例化！而 findViewById()是找具体某一个xml下的具体 widget控件(如:Button,TextView等)。

（0）她可以有很多地方可以使用，如BaseAdapter的getView中，自定义Dialog中取得view中的组件widget等等。
它的用法有2种：

Java代码

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);

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);

另一种方法：

Java代码

LayoutInflater inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);

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

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

上面2种方法本质上是一样的，看下面的源码，form()调用的就是getSystemService()：

Java代码

public static LayoutInflater from(Context context) {

LayoutInflater LayoutInflater =

(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

if (LayoutInflater == null) {

throw new AssertionError("LayoutInflater not found.");

}

return LayoutInflater;

}

public static LayoutInflater from(Context context) {
LayoutInflater LayoutInflater =
(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (LayoutInflater == null) {
throw new AssertionError("LayoutInflater not found.");
}
return LayoutInflater;
}

另外getSystemService()是Android很重要的一个API，它是Activity的一个方法，根据传入的NAME来取得对应的Object，然后转换成相应的服务对象。以下介绍系统相应的服务。

传入的Name	返回的对象	说明
WINDOW_SERVICE	WindowManager	管理打开的窗口程序
LAYOUT_INFLATER_SERVICE	LayoutInflater	取得xml里定义的view
ACTIVITY_SERVICE	ActivityManager	管理应用程序的系统状态
POWER_SERVICE	PowerManger	电源的服务
ALARM_SERVICE	AlarmManager	闹钟的服务
NOTIFICATION_SERVICE	NotificationManager	状态栏的服务
KEYGUARD_SERVICE	KeyguardManager	键盘锁的服务
LOCATION_SERVICE	LocationManager	位置的服务，如GPS
SEARCH_SERVICE	SearchManager	搜索的服务
VEBRATOR_SERVICE	Vebrator	手机震动的服务
CONNECTIVITY_SERVICE	Connectivity	网络连接的服务
WIFI_SERVICE	WifiManager	Wi-Fi服务
TELEPHONY_SERVICE	TeleponyManager	电话服务

Java代码

//基本用法

public void showCustomDialog(){

AlertDialog.Builder builder;

AlertDialog alertDialog;

Context mContext = AppActivity.this;

//下面俩种方法都可以

//LayoutInflater inflater = getLayoutInflater();

LayoutInflater inflater = (LayoutInflater)

mContext.getSystemService(LAYOUT_INFLATER_SERVICE);

View layout = inflater.inflate(R.layout.custom_dialog,null);

TextView text = (TextView) layout.findViewById(R.id.text);

text.setText("Hello, Welcome to Mr Wei's blog!");

ImageView image = (ImageView) layout.findViewById(R.id.image);

image.setImageResource(R.drawable.icon);

builder = new AlertDialog.Builder(mContext);

builder.setView(layout);

alertDialog = builder.create();

alertDialog.show();

}

}

protected void showToast(int type) {

Toast.makeText(this, "*********", Toast.LENGTH_LONG).show();

LayoutInflater li = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

View view = li.inflate(R.layout.toast, null);

Toast toast = new Toast(this);

toast.setView(view);

toast.setDuration(type);

toast.show();

}

//基本用法
public void showCustomDialog(){
AlertDialog.Builder builder;
AlertDialog alertDialog;
Context mContext = AppActivity.this;
//下面俩种方法都可以
//LayoutInflater inflater = getLayoutInflater();
LayoutInflater inflater = (LayoutInflater)
mContext.getSystemService(LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.custom_dialog,null);
TextView text = (TextView) layout.findViewById(R.id.text);
text.setText("Hello, Welcome to Mr Wei's blog!");
ImageView image = (ImageView) layout.findViewById(R.id.image);
image.setImageResource(R.drawable.icon);
builder = new AlertDialog.Builder(mContext);
builder.setView(layout);
alertDialog = builder.create();
alertDialog.show();
}
}

protected void showToast(int type) {
Toast.makeText(this, "*********", Toast.LENGTH_LONG).show();

LayoutInflater li = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = li.inflate(R.layout.toast, null);

Toast toast = new Toast(this);
toast.setView(view);
toast.setDuration(type);
toast.show();
}