ProgressBar 不会在启动屏幕上逐渐显示进度

Question

我有一个持续 5 秒的闪屏，我想使用 ProgressBar 来表示进度。

public class SplashActivity extends Activity {

    private static final long SPLASHTIME = 5000;
    private ProgressBar progressBar;

    @Override
    public void onCreate(Bundle icicle) {

        super.onCreate(icicle);
        setContentView(R.layout.splash);

        SplashHandler handlerSplash = new SplashHandler();
        progressBar = (ProgressBar) findViewById(R.id.progression);
        progressBar.setMax((int) ((SPLASHTIME) / 1000));
        progressBar.setProgress(0);
        Message msg = new Message();
        msg.what = 0;
        handlerSplash.sendMessageDelayed(msg, SPLASHTIME);


        ThreadProgressBar threadProgress = new ThreadProgressBar();
        threadProgress.start();


    }

    private class ThreadProgressBar extends Thread {
        ProgressBarHandler handlerProgress = new ProgressBarHandler();
        public void run() {
            try {

                while (progressBar.getProgress() <= progressBar.getMax()) {
                    Thread.sleep(1000);

                    handlerProgress.sendMessage(handlerProgress.obtainMessage());
                }
            } catch (java.lang.InterruptedException e) {

            }
        }
    }

        private class ProgressBarHandler extends Handler {

            public void handleMessage(Message msg) {
                progressBar
                        .incrementProgressBy((int) (SPLASHTIME / SPLASHTIME));
            }
        }

        private class SplashHandler extends Handler {

            public void handleMessage(Message msg) {
                switch (msg.what) {
                default:
                case 0:
                    super.handleMessage(msg);
                    // new ProgressBarIncrease().execute();
                    Intent intent = new Intent();
                    intent.setClass(SplashActivity.this, RdvTab.class);
                    startActivity(intent);

                }
            }
        }

Answer 1

我想既然 SplashActivity 本身就是一个 Activity，那么阻止 UI 就可以了，对吗？ AsyncTask有时运行不流畅，如果想让更新流畅显示，可以改成worker Thread和Handlder。

• 在 SplashActivity 中创建 Handler inside SplashActivity
• 在主线程中，显示​​进度条或启动栏或任何你喜欢的内容，
• 同时让另一个线程运行倒计时，每秒一次 sendEmptyMessage() 到处理程序。 5 秒后，向 Handler 发送消息以关闭对话框并启动，然后工作线程 Thread 结束。

更新：抱歉反馈缓慢。这个怎么样？我还没有测试过它，但这不是最好的实现，你可以使用这个逻辑

public class SplashActivity extends Activity {

    private static final int SPLASHTIME = 5000;
    // u can change the value here for smoother effect
    private static final long UPDATEINTERVAL = 1000;
    private ProgressBar progressBar;

    @Override
    public void onCreate(Bundle icicle) {

        super.onCreate(icicle);
        setContentView(R.layout.splash);

        progressBar = (ProgressBar) findViewById(R.id.progression);

        new Thread(new Runnable(){
            @Override
            public void run(){
                 int progress = 0;
                 while(true){
                     // send current progress to handler
                     mHandler.sendEmptyMessage(progress);
                     // break from the loop after SPLASHSCREEN millis
                     if(progress > SPLASHSCREEN)
                         break;
                     // increase the progress
                     progress = (int) (progress + UPDATEINTERVAL);
                     // sleep the worker thread
                     Thread.sleep(UPDATEINTERVAL);
                 }
            }
        }).start();
    }

    private Handler mHandler = new Handler(){
         @Override
         public void handleMessage(Message message){
             // get the current progress
             int progress = message.what;
             if(progress <= SPLASHTIME){
                 progressBar.setProgress(progress);
             }
             else{
                 // finish splashActivity here & do what u want do to after splashscreen, for example
                 finish();
                 Intent intent = new Intent(SpashActivity.this, MenuActivity.class);
                 startActivity(intent);
             }
         }
     }
 }

Answer 2

您应该将启动屏幕时间分成等量，并按这些时间间隔发送进度更新。

例如：假设总时间被分为 50 个相等的间隔，如下

protected void onPreExecute() {
         progressbarStep = progressbarWidth/50;
         timeStep = 5000/50;
         progress = 0;

    }

    @Override
    protected Void doInBackground(Void... params) {
        try {
            while(progress < progressbarWidth){
                progress += progressbarStep;
                publishProgress(progress);
                SystemClock.sleep(timeStep);
               }
               return null;
        } catch (Exception e) {

        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
         progressBar.setProgress(values[0]);
    }