PageJumpDialogFragment.java

package cl.monsoon.s1next.view.dialog;

import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.databinding.DataBindingUtil;
import android.os.Bundle;
import android.support.annotation.CallSuper;
import android.support.annotation.NonNull;
import android.support.v4.app.DialogFragment;
import android.text.TextUtils;
import android.widget.EditText;
import android.widget.SeekBar;

import cl.monsoon.s1next.R;
import cl.monsoon.s1next.databinding.DialogPageJumpBinding;
import cl.monsoon.s1next.util.ViewUtil;
import cl.monsoon.s1next.viewmodel.PageJumpViewModel;

/**
 * A dialog shows {@link SeekBar} and {@link EditText} to
 * display the page number you want to go to.
 * <p>
 * Host class should implement {@link OnPageJumpedListener}
 * in order to to handle the page jump event.
 */
public final class PageJumpDialogFragment extends DialogFragment {

    public static final String TAG = PageJumpDialogFragment.class.getName();

    private static final String ARG_TOTAL_PAGES = "total_pages";
    private static final String ARG_CURRENT_PAGE = "current_page";

    /**
     * The serialization (saved instance state) Bundle key representing
     * the SeekBar's progress.
     */
    private static final String STATE_SEEK_BAR_PROGRESS = "seek_bar_progress";

    private PageJumpViewModel mPageJumpViewModel;

    public PageJumpDialogFragment() {
        // Every fragment must have an empty constructor, so it
        // can be instantiated when restoring its activity's state.
    }

    @SuppressLint("ValidFragment")
    public PageJumpDialogFragment(int totalPages, int currentPage) {
        Bundle bundle = new Bundle();
        bundle.putInt(ARG_TOTAL_PAGES, totalPages);
        bundle.putInt(ARG_CURRENT_PAGE, currentPage);
        setArguments(bundle);
    }

    @NonNull
    @Override
    public final Dialog onCreateDialog(Bundle savedInstanceState) {
        DialogPageJumpBinding binding = DataBindingUtil.inflate(getActivity().getLayoutInflater(),
                R.layout.dialog_page_jump, null, false);

        int seekBarProgress;
        if (savedInstanceState == null) {
            seekBarProgress = getArguments().getInt(ARG_CURRENT_PAGE);
        } else {
            seekBarProgress = savedInstanceState.getInt(STATE_SEEK_BAR_PROGRESS);
        }

        // SeekBar max is zero-based
        mPageJumpViewModel = new PageJumpViewModel(getArguments().getInt(ARG_TOTAL_PAGES) - 1,
                seekBarProgress);
        binding.setPageJumpViewModel(mPageJumpViewModel);

        AlertDialog alertDialog = new AlertDialog.Builder(getContext())
                .setTitle(R.string.menu_page_jump)
                .setView(binding.getRoot())
                .setPositiveButton(R.string.dialog_button_text_jump, (dialog, which) -> {
                    if (!TextUtils.isEmpty(binding.value.getText())) {
                        ((OnPageJumpedListener) getParentFragment()).onPageJumped(
                                mPageJumpViewModel.getSeekBarProgress());
                    }
                })
                .setNegativeButton(android.R.string.cancel, null)
                .create();
        ViewUtil.consumeRunnableWhenImeActionPerformed(binding.value, () ->
                alertDialog.getButton(DialogInterface.BUTTON_POSITIVE).performClick());
        return alertDialog;
    }

    @Override
    @CallSuper
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        outState.putInt(STATE_SEEK_BAR_PROGRESS, mPageJumpViewModel.getSeekBarProgress());
    }

    /**
     * Callback interface for responding to page jump.
     */
    public interface OnPageJumpedListener {

        /**
         * This method will be invoked when a page is selected.
         *
         * @param position Position index of the new selected page.
         */
        void onPageJumped(int position);
    }
}