如何禁用按钮一天

Question

I want to disable the upload button for one day for after uploading firebase photo. i tried these codes, countdown works incorrectly when I change activity.

   SharedPreferences prefs = getSharedPreferences("time", Context.MODE_PRIVATE);
                long currentTime = new Date().getTime();
                SharedPreferences.Editor editor = prefs.edit();
                editor.putLong("time", currentTime);
                editor.apply();
                dwn.setEnabled(false);



    SharedPreferences prefs = getSharedPreferences("time", Context.MODE_PRIVATE);
    long previousTime = prefs.getLong("time", 0);
    long currentTime = new Date().getTime();
    if (currentTime - previousTime > 60*1000){

        dwn.setEnabled(true);
    } else {
        dwn.setEnabled(false);
        new CountDownTimer(currentTime - previousTime, 1000) {
            public void onTick(long millisUntilFinished) {
                dwn.setText("fdfjhsn" + millisUntilFinished / 1000);
            }

            public void onFinish() {
                dwn.setEnabled(true);
            }
        }.start();

Answer 1

This might be more than you were looking for, but I would extract the decision making to a separate class. Consider the following:

interface UserUploadHelper {
    void userUploadedImage();
    boolean canUserUploadImages();
}

We can have an implementation of this, backed by SharedPreferences. This object can then be injected into wherever we need it:

class SharedPreferencesUserUploadHelper implements UserUploadHelper {
    private static final String LAST_IMAGE_UPLOAD_TIME = "last.user.upload.time";
    private static final String PREFS_NAME = "user.upload";
    private static final String PREFS_MODE = Context.MODE_PRIVATE;
    private static final String MILLIS_IN_DAY = 24 * 60 * 60 * 1000;

    private final SharedPreferences sharedPreferences;

    SharedPreferencesUserUploadHelper(Context context) {
        sharedPreferences = context.getSharedPreferences(PREFS_NAME, PREFS_MODE);
    }

    @Override
    void userUploadedImage() {
        sharedPreferences.edit().putLong(
            LAST_IMAGE_UPLOAD_TIME, 
            new Date().getTime()
        ).apply();
    }

    @Override
    boolean canUserUploadImages() {
        long lastUploadTime = sharedPreferences.getLong(LAST_IMAGE_UPLOAD_TIME, 0L);
        long now = new Date().getTime();
        return lastUploatTime - now > MILLIS_IN_DAY;
    }
}

Inside your upload code, when the code finishes uploading, you can call userUploadedImage()

Inside your activity code, you can check whether the button should be enabled with canUserUploadImages() .

Doing this lets you change how you store that value and calculate the timeout without changing your firebase logic or your view logic.

You can inject this into a class using a tool like Dagger , or simply by creating an instance of it via its constructor. If you want to hide the concrete SharedPreferencesUserUploadHelper implementation, you can use a factory! This is good when you might decide to change how this class is implemented later.

public UserUploadHelperFactory {
    public UserUploadHelper create(Context context) {
        return new SharedPreferencesUploadHelper();
    }
}

If we wanted to go a step further, we would actually break our original interface into two different interfaces, one for each method, since each method has different interested parties, and, for example, the view shouldn't be able to call userUploadedImage (Which makes that original interface a slight violation of the Interface Segregation Principle!)