如何在一定时间后显示 ProgressBar

Question

我正在使用 Android API 23 级 (Android 6)。我正在使用 com.loopj.android.http.AsyncHttpClient 来实现与我的后端服务器的异步通信，它工作正常。

在与服务器通信时，我显示了一个进度条像这样：

findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);

并像这样隐藏它：

findViewById(R.id.loadingPanel).setVisibility(View.GONE);

完成时 suggested here。

它运行得非常好。

现在大多数时候，对服务器的请求只需要几毫秒，所以显示和隐藏进度条会导致一些闪烁，如果请求时间只有那么短，这是不必要的而且很烦人。

仅在请求开始后一定时间后才显示进度条的好方法是什么，比方说一秒后？

Answer 1

您可以像这样在显示进度条之前设置延迟：

Handler myHandler = new Handler();
myHandler.postDelayed(new Runnable() {
    @Override
    public void run() {
        // Do something after 1s = 1000ms
        findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);
    }
}, 1000);

Answer 2

我猜你做了类似下面的事情

 AsyncHttpClient client = new AsyncHttpClient();
 client.get("https://www.example.com", new AsyncHttpResponseHandler() {

    @Override
    public void onStart() {
        // called before request is started
       findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);
    }

    @Override
    public void onSuccess(int statusCode, Header[] headers, byte[] response) {
        // called when response HTTP status is "200 OK"
        findViewById(R.id.loadingPanel).setVisibility(View.GONE);
    }

    @Override
    public void onFailure(int statusCode, Header[] headers, byte[] errorResponse, Throwable e) {
        // called when response HTTP status is "4XX" (eg. 401, 403, 404)
    }

    @Override
    public void onRetry(int retryNo) {
        // called when request is retried
    }
});

只需尝试以下

boolean showProgress= true;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    AsyncHttpClient client = new AsyncHttpClient();
    client.get("https://www.google.com", new AsyncHttpResponseHandler() {

        @Override
        public void onStart() {
            // called before request is started
            //findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);

            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    if(showProgress){
                        findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);
                    }
                }
            }, 5*1000); // your progress will start after 5 seconds
        }

        @Override
        public void onSuccess(int statusCode, Header[] headers, byte[] response) {
            // called when response HTTP status is "200 OK"
            //findViewById(R.id.loadingPanel).setVisibility(View.GONE);
            showProgress = false;
        }

        @Override
        public void onFailure(int statusCode, Header[] headers, byte[] errorResponse, Throwable e) {
            // called when response HTTP status is "4XX" (eg. 401, 403, 404)
            showProgress = false;
        }

        @Override
        public void onRetry(int retryNo) {
            // called when request is retried
        }
    });
}

Answer 3

您可以使用最初设置为 true 的布尔标志变量。然后当您收到来自服务器的响应时，您可以翻转标志值。然后你可以使用这样的处理程序：

Handler myHandler = new Handler();
myHandler.postDelayed(new Runnable() {
    @Override
    public void run() {
        if(flag)
            findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);            
    }
}, 1000);

Handler endHandler = new Handler();
    endHandler.postDelayed(new Runnable() {
        @Override
        public void run() {
                findViewById(R.id.loadingPanel).setVisibility(View.GONE);            
        }
    }, MAX_WAIT_TIME_YOU_WANT);

Answer 4

您可以简单地在第二个滴答中使用 CountDownTimer。像这样：

 private boolean mNeedToCloseProgress = false;
 // in second with 100 ms tick
 CountDownTimer mCdtStartProgress = new CountDownTimer(1000, 1000) {

     public void onTick(long millisUntilFinished) {}

     public void onFinish() {
        mNeedToCloseProgress = true;
        findViewById(R.id.loadingPanel).setVisibility(View.VISIBLE);
     }
  };

然后当你开始api调用时，你需要启动定时器：

mCdtStartProgress.start();

这将修改标志mNeedToCloseProgress指示进度是否需要关闭。

然后在您完成调用 api 并获得结果时取消计时器：

mCdtStartProgress.cancel();
if(mNeedToCloseProgress) findViewById(R.id.loadingPanel).setVisibility(View.GONE);

如何在一定时间后显示 ProgressBar

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