android 启动界面

　　很多应用都会有一个启动界面。启动画面，展示自己的LOGO、本版信息等，欢迎画面慢慢隐现，然后慢慢消隐。
　　实现这种效果的方法有两种:

　　1、使用两个Activity，程序启动时候load第一张Activity，然后由tick触发N秒钟后startActivity另外一张Activity。
　　2、使用一个Activity，可以用到View.gone() 这个方法。把Acitivity的某些元素移除。

　　使用两个Activity

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.Window;
//SplashActivity    注意要在AndroidManifest.xml配置为启动页
public class SplashActivity extends Activity {
	public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);// 去掉标题栏
        setContentView(R.layout.splash);
        MyApplication.getInstance().addActivity(this);
        Handler x = new Handler();
        x.postDelayed(new splashhandler(), 2000); //设置延迟执行时间
    }
	
    class splashhandler implements Runnable{
        public void run() {
            startActivity(new Intent(getApplication(),LoginActivity.class));  //启动主Activity
            SplashActivity.this.finish();  // 关闭启动页Activity
        }
    }
}

 　　启动页布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_height="fill_parent" 
  android:layout_width="fill_parent" 
  android:orientation="vertical" 
  android:background="#ff0099d6">
	<ImageView 
	    android:layout_height="fill_parent" 
	    android:layout_width="fill_parent" 
	    android:scaleType="fitCenter" 
	    android:src="@drawable/qidongye">
	</ImageView>
</LinearLayout>

 　　使用一个Activity

public class WebGameActivity extends Activity { 
  private WebView webView;   
  private Handler mHandler = new Handler(); 
  private static final String TAG = "WebGameActivity";   
  //菜单 
  private static final int MENU_RELOAD = Menu.FIRST; 
  private static final int MENU_HELP = Menu.FIRST + 1; 
  private static final int MENU_ABOUT = Menu.FIRST + 2; 
  private static final int MENU_CLOSE = Menu.FIRST + 3;   
  private int staus  = 0;  
  private static final int  STOPSPLASH = 0; 
  //延迟时间 
  private static final long SPLASHTIME = 1000; 
  private LinearLayout splash; 
  private TextView tv; 
  private Animation myAnimation_Alpha; 
  private Animation animatinoGone ; 
  
  private Handler splashHandler = new Handler() { 
    public void handleMessage(Message msg) { 
         switch (msg.what) { 
         case STOPSPLASH: 
              if( staus == 1 ){                
                splash.startAnimation(animatinoGone); 
                splash.setVisibility(View.GONE); 
                break; 
              } 
              sendEmptyMessageDelayed(STOPSPLASH, SPLASHTIME); 
         } 
         super.handleMessage(msg); 
    } 
}; 
  
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    getWindow().requestFeature(Window.FEATURE_PROGRESS); //去标题栏 
    setContentView(R.layout.main);    
    animatinoGone = AnimationUtils.loadAnimation(this,R.anim.alpha_gone); //动画效果 
    myAnimation_Alpha = AnimationUtils.loadAnimation(this,R.anim.alpha_action); //动画效果 
    
    splash = (LinearLayout) findViewById(R.id.splashscreen); 
    tv = (TextView) findViewById(R.id.info); 
    tv.setText("正在建立数据连接"); 
    splash.startAnimation(myAnimation_Alpha); 
    
    Message msg = new Message(); 
    msg.what = STOPSPLASH; 
    splashHandler.sendMessageDelayed(msg, SPLASHTIME); 
}

 　　布局文件

<?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”>   
     <LinearLayout android:id=”@+id/splashscreen” android:orientation=”vertical”
          android:layout_width=”fill_parent” android:layout_height=”fill_parent”>
          <ImageView  android:layout_width=”wrap_content”
               android:layout_height=”wrap_content” android:src=”@drawable/splash”
               android:layout_gravity=”center”
               android:layout_marginTop=”130px”/>
          <TextView
               android:id=”@+id/info”
               android:layout_width=”fill_parent”
               android:layout_height=”wrap_content”
               android:gravity=”center”
               android:paddingTop=”10px”
               android:text=”This is a splash!!”/>
     </LinearLayout>     
 <WebView android:id=”@+id/browser”
  android:layout_width=”fill_parent”
  android:layout_height=”fill_parent” android:layout_weight=”1″/>
</LinearLayout>

 有一个id为splashscreen 的linearlayout，是程序启动时显现的部分。id为browser是程序的主界面显示部分。