Question

我的应用程序中有一个进度条。我正在调用意图服务来下载大尺寸的文件。服务开始下载时，进度条正在正确更新。当我从设备上单击后退按钮时，意图服务仍在后台运行，进度条计数也在后台更新，但是当我再次打开应用程序时，即使进度条计数从哪里开始，进度条也不会更新值我离开了。你能帮我解决这个问题吗？

这是我在布局文件中的进度条，

<ProgressBar
    android:id="@+id/progressBar2"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:layout_marginTop="20dp"
    android:indeterminate="false"
    android:max="100"
    android:minHeight="50dp"
    android:minWidth="200dp"
    android:progress="1" />

这是我更新进度条的java文件。进度意图将包含进度更新的当前计数。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    sharedPref = getPreferences(Context.MODE_PRIVATE);
    progressBar2 = (ProgressBar) findViewById(R.id.progressBar2);
    updateReceiver = new CheckNetworkConnectivity(
            new NetworkReceiverCallback() {
                @Override
                public void onNetworkReceived(int status) {
                    networkStaus = status;
                    if (networkStaus == 0) {

                        Toast.makeText(
                                getApplicationContext(),
                                "Download interrupted due to network issue.",
                                Toast.LENGTH_SHORT).show();

                    } else {
                        onCallService(fileLength, currentDate, downloaded, Constants.downloadStatus);
                        Toast.makeText(getApplicationContext(),
                                    "Start downloading....",
                                    Toast.LENGTH_SHORT).show();
                    }
                }
            });

    registerReceiver(updateReceiver, new IntentFilter(
        ConnectivityManager.CONNECTIVITY_ACTION));

    activity = this;

}

private void onCallService(long downloaded, String lastModifiedDate, long size, int downloadStatus) {
    mReceiver = new DownloadResultReceiver(new Handler());
    mReceiver.setReceiver(this);
    Intent intent = new Intent(Intent.ACTION_SYNC, null, this,
            DownloadBackgroundService.class);

    String url = "";

    intent.putExtra("url", url);
    intent.putExtra("receiver", mReceiver);
    intent.putExtra("downloaded", downloaded);
    intent.putExtra("downloadStatus", downloadStatus);
    intent.putExtra("size", size);
    intent.putExtra("lastModifiedDate", lastModifiedDate);

    startService(intent);

}

@Override
public void onReceiveResult(int resultCode, Bundle resultData) {
    int progress = resultData.getInt("progress");
    progressBar.setProgress(progress);
    progressBar.setMax(100);
    progressBar.setText(String.valueOf(progress) + "/100");
    progressBar2.invalidate();
    progressBar2.setProgress(progress);
    progressBar2.isFocused();
    Log.d("DownloadService", "Progress bar is updating : " + progress);
}

@Override
protected void onStart() {

    progressBar = (TextProgressBar) findViewById(R.id.progressBar1);
    progressBar.setProgress(0);
    progressBar.setMax(100);

    progressBar.setText(String.valueOf(0) + "/100");
    super.onStart();
}

@Override
protected void onRestart() {

    super.onRestart();
}

@Override
protected void onResume() {

    super.onResume();
}

@Override
protected void onStop() {
    super.onStop();
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(updateReceiver);
}

Answer 1

请更改：

android:layout_width="wrap_content"

到

android:layout_width="match_parrent"

Answer 2

如果您可以在日志中看到修改后的值，并且只在输出中看不到它，请尝试progressBar.invalidate（）;

Answer 3

首先来看看下面的活动生命周期：

当我再次打开应用程序时，即使进度条计数从我离开的位置开始，进度条也不会更新值

当您通过单击后退按钮退出应用程序时，属于活动的每个资源都将被销毁。然后，当您再次打开应用程序时，将再次重新提供您的资源。这意味着当您再次打开应用时，当您致电progressBar2 = (ProgressBar) findViewById(R.id.progressBar2);时，您的进度条将初始化为新实例

我建议解决方案是每次收到下载进度的价值，将其保存到数据库或首选项中，然后在打开应用程序时将其恢复：

@Override
public void onReceiveResult(int resultCode, Bundle resultData) {
int progress = resultData.getInt("progress"); // <---- SAVE THIS VALUE
progressBar.setProgress(progress);
progressBar.setMax(100);
progressBar.setText(String.valueOf(progress) + "/100");
progressBar2.invalidate();
progressBar2.setProgress(progress);
progressBar2.isFocused();
Log.d("DownloadService", "Progress bar is updating : " + progress);
}


@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

sharedPref = getPreferences(Context.MODE_PRIVATE);
progressBar2 = (ProgressBar) findViewById(R.id.progressBar2);
progressBar2.setProgress(progress); // GET SAVED VALUE AND SET IT INTO PROGRESS

Answer 4

错误的帖子。＆＃34; onReceiveResult＆＃34;是一个异步事件，即可能不会在UI线程中。使用mActivity.runOnUiThread更新UI。

单击“返回”按钮时，Progressbar未更新该值

4 个答案: