public class WelcomeActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.welcome);
        
        
        //1.拿到當前acitivity的layout的view
        View view  = findViewById(R.id.welcome_layout);
        
        //2.繫結透明度變化的動畫
        AlphaAnimation anim = new AlphaAnimation(0.1f, 1.0f);
        anim.setDuration(3000);
        view.startAnimation(anim);
        
        //3.動畫執行完畢後，進入主頁面
        anim.setAnimationListener(am);

    }
    
    private AnimationListener am = new AnimationListener() {
    	@Override
		public void onAnimationEnd(Animation animation) {
    		//動畫執行結束的時候去主頁面
    		Intent intent = new Intent();
    		intent.setClass(WelcomeActivity.this, PageActivity.class);
    		startActivity(intent);
    		finish();
		}
		@Override
		public void onAnimationStart(Animation animation) {
		}
		
		@Override
		public void onAnimationRepeat(Animation animation) {
		}
	};

	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		//監聽的back鍵按下的時候什麼也不處理
		//直接在當前頁面忽略任何按鍵
//		if (keyCode == KeyEvent.KEYCODE_BACK) {
//			//監聽到返回鍵，
//		}
		return false;
	}
}