android 啟動動畫的漸變

一.啟動動畫的漸變：

以後可能會用到的啟動動畫的效果：

效果圖：

主界面：

 

public class MainActivity extends Activity {
    private LandingView lv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        lv = new LandingView(this);
		// 將自定義視圖顯示在本界面
		setContentView(lv);
		// 創建修改Logo透明度的異步任務
		LoGoTask task = new LoGoTask(this,lv);
		// 執行異步任務
		task.execute();
    }
}

異步圖片漸變：

 

 

public class LoGoTask extends AsyncTask

顯示圖片制作：

 

 

public class LandingView extends View{
	    
		private  int alpha = 0;
		
		private Bitmap logo;
		private Context context;
		public LandingView(Context context) {
			super(context);
			this.context = context;
			logo = BitmapFactory.decodeResource(context.getResources(),
					R.drawable.background1);
		}
		public void redraw(int aplha){
	       this.alpha = aplha;
	       invalidate();
		}
		@Override
		protected void onDraw(Canvas canvas) {
			// TODO Auto-generated method stub
			super.onDraw(canvas);
			// 清屏
			canvas.drawColor(Color.WHITE);
			// 創建畫筆對象
			Paint p = new Paint();
			// 設置畫筆對象的透明度為當前透明度取值
			p.setAlpha(alpha);
			WindowManager manager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
			DisplayMetrics dm=new DisplayMetrics();
			manager.getDefaultDisplay().getMetrics(dm);
			int width2=dm.widthPixels;
			int height2=dm.heightPixels;
			// 在視圖上利用畫筆繪制Logo圖像
			RectF rect = new RectF(0,0,width2,height2);
			canvas.drawBitmap(logo, null, rect, p);
		}
}

再來個進入界面：

 

 

public class TestActivity extends Activity{
	 @Override
	    protected void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);
	        setContentView(R.layout.activity_main);

	    }
}