Question

我有一个带圆形进度条的柜台。计数器启动时，进度条也从计数器值开始，但是当它在后台运行并再次打开应用程序时...圆形进度条从0开始，但计数器按值正确运行。在这种情况下，我需要进度条不要从0开始。

这是我的代码：

public class MainActivity extends AppCompatActivity {
    public int counter;
    Button button;
    public boolean isrunningtime = false;
    TextView textView;
    private ProgressBar progressBar;
    long millisUntilFinished = 0;
    SharedPreferences sharedPreferences;
    SharedPreferences.Editor editor;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.textView);
        sharedPreferences = getSharedPreferences("my", MODE_PRIVATE);
        editor = sharedPreferences.edit();
        progressBar = findViewById(R.id.progressBar);
        startService(new Intent(this, BroadcastService.class));
        Log.i("Tag", "Started service");
    }

    private BroadcastReceiver br = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            updateGUI(intent); // or whatever method used to update your GUI fields
        }
    };

    @Override
    public void onResume() {
        super.onResume();
        registerReceiver(br, new IntentFilter(BroadcastService.COUNTDOWN_BR));

        Log.i("Tag", "Registered broacast receiver");
    }

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(br);


    }

    @Override
    public void onStop() {
        try {
            unregisterReceiver(br);
        } catch (Exception e) {
            // Receiver was probably already stopped in onPause()
        }
        super.onStop();
    }

    @Override
    public void onDestroy() {
        stopService(new Intent(this, BroadcastService.class));
        Log.i("Tag", "Stopped service");
        super.onDestroy();
    }

    private void updateGUI(Intent intent) {
        if (intent.getExtras() != null) {
            millisUntilFinished = intent.getLongExtra("countdown", 0);
            Log.i("Tag", "Countdown seconds remaining: " + millisUntilFinished / 1000);

                progressBar.setProgress((int) (millisUntilFinished / 1000));

            Log.i("progress", "" + (int) (millisUntilFinished / 1000));
            textView.setText("" + millisUntilFinished / 1000);
        }

    }


}

Answer 1

仅在unregisterReceiver(br)中放入onDestroy()，而不是onStop()和onPause()

Answer 2

从onStop（）和onPause（）中删除unregisterReceiver(br);，并将registerReceiver(br, new IntentFilter(BroadcastService.COUNTDOWN_BR));从onResume（）移至onCreate（）

在Android Progressar中，当应用程序处于后台时会重置其值

2 个答案: