TwoStatePreference.java

package com.jenzz.materialpreference;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.View;

import static android.text.TextUtils.isEmpty;

public abstract class TwoStatePreference extends Preference {

  private CharSequence summaryOn;
  private CharSequence summaryOff;
  private boolean isChecked;
  private boolean isCheckedSet;
  private boolean disableDependentsState;

  public TwoStatePreference(Context context) {
    super(context);
  }

  public TwoStatePreference(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

  public TwoStatePreference(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }

  public TwoStatePreference(Context context, AttributeSet attrs, int defStyleAttr,
      int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
  }

  @Override
  protected void onClick() {
    super.onClick();

    boolean newValue = !isChecked();
    if (callChangeListener(newValue)) {
      setChecked(newValue);
    }
  }

  /**
   * Sets the checked state and saves it to the {@link SharedPreferences}.
   *
   * @param checked
   *     The checked state.
   */
  public void setChecked(boolean checked) {
    // Always persist/notify the first time; don't assume the field's default of false.
    boolean changed = isChecked != checked;
    if (changed || !isCheckedSet) {
      isChecked = checked;
      isCheckedSet = true;
      persistBoolean(checked);
      if (changed) {
        notifyDependencyChange(shouldDisableDependents());
        notifyChanged();
      }
    }
  }

  /**
   * Returns the checked state.
   *
   * @return The checked state.
   */
  public boolean isChecked() {
    return isChecked;
  }

  @Override
  public boolean shouldDisableDependents() {
    boolean shouldDisable = disableDependentsState ? isChecked : !isChecked;
    return shouldDisable || super.shouldDisableDependents();
  }

  /**
   * Sets the summary to be shown when checked.
   *
   * @param summary
   *     The summary to be shown when checked.
   */
  public void setSummaryOn(CharSequence summary) {
    summaryOn = summary;
    if (isChecked()) {
      notifyChanged();
    }
  }

  /**
   * @param summaryResId
   *     The summary as a resource.
   *
   * @see #setSummaryOn(CharSequence)
   */
  public void setSummaryOn(int summaryResId) {
    setSummaryOn(getContext().getString(summaryResId));
  }

  /**
   * Returns the summary to be shown when checked.
   *
   * @return The summary.
   */
  public CharSequence getSummaryOn() {
    return summaryOn;
  }

  /**
   * Sets the summary to be shown when unchecked.
   *
   * @param summary
   *     The summary to be shown when unchecked.
   */
  public void setSummaryOff(CharSequence summary) {
    summaryOff = summary;
    if (!isChecked()) {
      notifyChanged();
    }
  }

  /**
   * @param summaryResId
   *     The summary as a resource.
   *
   * @see #setSummaryOff(CharSequence)
   */
  public void setSummaryOff(int summaryResId) {
    setSummaryOff(getContext().getString(summaryResId));
  }

  /**
   * Returns the summary to be shown when unchecked.
   *
   * @return The summary.
   */
  public CharSequence getSummaryOff() {
    return summaryOff;
  }

  /**
   * Returns whether dependents are disabled when this preference is on ({@code true})
   * or when this preference is off ({@code false}).
   *
   * @return Whether dependents are disabled when this preference is on ({@code true})
   * or when this preference is off ({@code false}).
   */
  public boolean getDisableDependentsState() {
    return disableDependentsState;
  }

  /**
   * Sets whether dependents are disabled when this preference is on ({@code true})
   * or when this preference is off ({@code false}).
   *
   * @param disableDependentsState
   *     The preference state that should disable dependents.
   */
  public void setDisableDependentsState(boolean disableDependentsState) {
    this.disableDependentsState = disableDependentsState;
  }

  @Override
  protected Object onGetDefaultValue(TypedArray a, int index) {
    return a.getBoolean(index, false);
  }

  @Override
  protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
    setChecked(restoreValue ? getPersistedBoolean(isChecked) : (Boolean) defaultValue);
  }

  /**
   * Sync a summary view contained within view's subhierarchy with the correct summary text.
   *
   * @param view
   *     View where a summary should be located
   */
  void syncSummaryView(View view) {
    // Sync the summary view
    boolean useDefaultSummary = true;
    if (isChecked && !isEmpty(summaryOn)) {
      summaryView.setText(summaryOn);
      useDefaultSummary = false;
    } else if (!isChecked && !isEmpty(summaryOff)) {
      summaryView.setText(summaryOff);
      useDefaultSummary = false;
    }

    if (useDefaultSummary) {
      CharSequence summary = getSummary();
      if (!isEmpty(summary)) {
        summaryView.setText(summary);
        useDefaultSummary = false;
      }
    }

    int newVisibility = View.GONE;
    if (!useDefaultSummary) {
      // Someone has written to it
      newVisibility = View.VISIBLE;
    }
    if (newVisibility != summaryView.getVisibility()) {
      summaryView.setVisibility(newVisibility);
    }
  }

  @Override
  protected Parcelable onSaveInstanceState() {
    Parcelable superState = super.onSaveInstanceState();
    if (isPersistent()) {
      // No need to save instance state since it's persistent
      return superState;
    }

    SavedState myState = new SavedState(superState);
    myState.checked = isChecked();
    return myState;
  }

  @Override
  protected void onRestoreInstanceState(Parcelable state) {
    if (state == null || !state.getClass().equals(SavedState.class)) {
      // Didn't save state for us in onSaveInstanceState
      super.onRestoreInstanceState(state);
      return;
    }

    SavedState myState = (SavedState) state;
    super.onRestoreInstanceState(myState.getSuperState());
    setChecked(myState.checked);
  }

  static class SavedState extends BaseSavedState {

    boolean checked;

    public SavedState(Parcel source) {
      super(source);
      checked = source.readInt() == 1;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
      super.writeToParcel(dest, flags);
      dest.writeInt(checked ? 1 : 0);
    }

    public SavedState(Parcelable superState) {
      super(superState);
    }

    public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
      public SavedState createFromParcel(Parcel in) {
        return new SavedState(in);
      }

      public SavedState[] newArray(int size) {
        return new SavedState[size];
      }
    };
  }
}