在进入程序前,一般都要有一个欢迎图片LOGO或者动画,等待几秒后隐藏Logo或做Intent跳转:
可以使用HandlerThread新建一个线程来执行等待动作,也可以使用Android的TimerTask:
1.HandlerThread:
public class WelcomeAct extends Activity { protected static final String TAG = "WelcomeAct"; private Handler handler; //因为要重写构造方法,所以不能用匿名内部类 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 设置登录无标题栏 requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.welcome); HandlerThread myThread = new HandlerThread("myHandlerThread"); myThread.start(); handler = new myHandler(myThread.getLooper()); handler.post(new Runnable() { @Override public void run() { try { //耗时的操作 Thread.sleep(2500); //handler主要用于异步消息的处理,使用sendMessage()后,方法立即返回,Message放入消息队列, //等待Message出消息队列,由handlerMessage(Message msg)通知UI线程子线程已经挂起,并使用返回的msg。 handler.sendMessage(handler.obtainMessage()); } catch (InterruptedException e) { e.printStackTrace(); } } }); } class myHandler extends Handler{ public myHandler(Looper looper) { super(looper); } //负责从消息队列中取消息给UI线程 @Override public void handleMessage(Message msg) { super.handleMessage(msg); Intent intent = new Intent(WelcomeAct.this, LoginAct.class); startActivity(intent); } } }
2.使用TimerTask:
public class WelcomeAct extends Activity { protected static final int LOGINOVER = 0; protected static final String TAG = "WelcomeAct"; private Handler handler; //因为要重写构造方法,所以不能用匿名内部类 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 设置登录无标题栏 requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.welcome); ProgressBar loading = (ProgressBar)findViewById(R.id.loading); loading.setVisibility(View.VISIBLE); HandlerThread myThread = new HandlerThread("myHandlerThread"); myThread.start(); handler = new Handler(){ @Override public void handleMessage(Message msg) { if(msg.what == LOGINOVER){ Log.i(TAG, Thread.currentThread().getName()); Intent intent = new Intent(WelcomeAct.this, LoginAct.class); startActivity(intent); } } }; tt.run(); } TimerTask tt = new TimerTask() { @Override public void run() { Log.i(TAG, Thread.currentThread().getName()); handler.sendMessageDelayed(handler.obtainMessage(LOGINOVER), 3000); } }; }
也可设计为没有Intent跳转,使用View.setVisibility(View.GONE);和 View.VISIBLE来达到想要的效果。
使用TimerTask,打印线程名可以看出,系统没有新开线程,而且达到了阻塞等待的目的,代码量小,推荐用。