WifiManager wifiMgr = (WifiManager) getActivity().getSystemService(Context.WIFI_SERVICE); 
WifiInfo wifiInfo = wifiMgr.getConnectionInfo(); 
String name = wifiInfo.getSSID(); 

1.<?xml version="1.0" encoding="utf-8"?> 
 
 
<TextView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@android:id/text1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceMedium" 
    android:gravity="center_vertical" 
    android:padding="5dip" 
    android:background="@color/darkblue" 
    android:drawableLeft="@drawable/yourPicture" 
 
/>  
2.<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent"  
 android:layout_height="wrap_content" 
    android:layout_gravity="center_horizontal"> 
<ImageView 
        android:id="@+id/myIcon" 
        android:layout_width="25px" 
        android:layout_height="25px"        
        android:layout_alignParentTop="true" 
        android:layout_alignParentBottom="true" 
        android:layout_centerVertical="true" 
        android:focusable="false" 
        android:padding="4px" 
        />   
<TextView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@android:id/text1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceMedium" 
    android:gravity="center_vertical" 
    android:padding="5dip" 
    android:background="@color/darkblue" 
android:layout_toRightOf="@id/myIcon"   
/>    
 
</RelativeLayout> 

这个简单的例子是EditText中默认有个字符串text，单击Show按钮，弹出AlertDialog显示EditText中的内容，单击Clear按钮，清除EditText中的内容！！
 效果图：

Activity用到两个LinearLayout,两个Button,一个TextView,一个EditText！

main.xml代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<EditText
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/text"
    android:id="@+id/text"
    />
<LinearLayout
	android:id="@+id/linearlayout1"
	android:layout_width="fill_parent"
	android:layout_height="wrap_content"
	android:gravity="center"
	>
	<Button
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="@string/btnShow"
		android:id="@+id/btnShow"
		/>
	<Button
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="@string/btnClear"
		android:id="@+id/btnClear"
		/>
</LinearLayout>
</LinearLayout>

 java代码为：

import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class practice extends Activity {
	Button btnShow;
    Button btnClear;
    EditText text;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        btnShow = (Button)findViewById(R.id.btnShow);
        btnClear = (Button)findViewById(R.id.btnClear);
        text = (EditText)findViewById(R.id.text);
        
        btnShow.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
					new AlertDialog.Builder(practice.this)
					.setTitle("Infomation")
					.setIcon(android.R.drawable.ic_dialog_dialer)
					.setMessage(text.getText())
					.show();
			}
		});
        
        btnClear.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				text.setText("");
			}
		});
    }
}