你好

一
package cn.edu.bzu.helloandroid;

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

public class MainActivity extends Activity
{
	private Button btnClick;
	private EditText etName;
	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		btnClick=(Button) findViewById(R.id.btnClick);
		btnClick.setOnClickListener(new ClickHandler());
		
		etName=(EditText) findViewById(R.id.etName);

	}

	class ClickHandler implements OnClickListener
	{

		@Override
		public void onClick(View view)
		{
			String  name=etName.getText().toString();
			Toast.makeText(MainActivity.this, "你好！"+name, Toast.LENGTH_LONG)
					.show();

		}
	}

}
二
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/bg" >

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="21dp"
        android:layout_marginTop="68dp"
        android:background="@android:drawable/edit_text"
        android:drawableLeft="@drawable/name"
        android:ems="10"
        android:hint="@string/etNamePrompt" />

    <Button
        android:id="@+id/btnClick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/btnClick" />

</RelativeLayout>
三
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.edu.bzu.helloandroid"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity android:name="cn.edu.bzu.helloandroid.MainActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>