material-components_material-components-android/lib/java/com/google/android/material/internal/CheckableImageButton.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.material.internal;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.content.Context;
import android.os.Parcel;
import android.os.Parcelable;
import androidx.appcompat.widget.AppCompatImageButton;
import android.util.AttributeSet;
import android.view.View;
import android.view.accessibility.AccessibilityEvent;
import android.widget.Checkable;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
import androidx.core.view.AccessibilityDelegateCompat;
import androidx.core.view.ViewCompat;
import androidx.core.view.accessibility.AccessibilityEventCompat;
import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
import androidx.customview.view.AbsSavedState;

/** @hide */
@RestrictTo(LIBRARY_GROUP)
public class CheckableImageButton extends AppCompatImageButton implements Checkable {

  private static final int[] DRAWABLE_STATE_CHECKED = new int[] {android.R.attr.state_checked};

  private boolean checked;
  private boolean checkable = true;
  private boolean pressable = true;

  @Nullable
  private OnFocusableChangedListener onFocusableChangedListener;

  public CheckableImageButton(Context context) {
    this(context, null);
  }

  public CheckableImageButton(Context context, AttributeSet attrs) {
    this(context, attrs, androidx.appcompat.R.attr.imageButtonStyle);
  }

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

    ViewCompat.setAccessibilityDelegate(
        this,
        new AccessibilityDelegateCompat() {
          @Override
          public void onInitializeAccessibilityEvent(View host, @NonNull AccessibilityEvent event) {
            super.onInitializeAccessibilityEvent(host, event);
            event.setChecked(isChecked());
          }

          @Override
          public void onInitializeAccessibilityNodeInfo(
              View host, @NonNull AccessibilityNodeInfoCompat info) {
            super.onInitializeAccessibilityNodeInfo(host, info);
            info.setCheckable(isCheckable());
            info.setChecked(isChecked());
          }
        });
  }

  @Override
  public void setChecked(boolean checked) {
    if (checkable && this.checked != checked) {
      this.checked = checked;
      refreshDrawableState();
      sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
    }
  }

  @Override
  public boolean isChecked() {
    return checked;
  }

  @Override
  public void toggle() {
    setChecked(!checked);
  }

  @Override
  public void setPressed(boolean pressed) {
    if (pressable) {
      super.setPressed(pressed);
    }
  }

  @Override
  public void setFocusable(boolean focusable) {
    boolean originalFocusable = isFocusable();
    super.setFocusable(focusable);

    if (originalFocusable != focusable && onFocusableChangedListener != null) {
      onFocusableChangedListener.onFocusableChanged(this, focusable);
    }
  }

  @Override
  public int[] onCreateDrawableState(int extraSpace) {
    if (checked) {
      return mergeDrawableStates(
          super.onCreateDrawableState(extraSpace + DRAWABLE_STATE_CHECKED.length),
          DRAWABLE_STATE_CHECKED);
    } else {
      return super.onCreateDrawableState(extraSpace);
    }
  }

  @NonNull
  @Override
  protected Parcelable onSaveInstanceState() {
    Parcelable superState = super.onSaveInstanceState();
    SavedState savedState = new SavedState(superState);
    savedState.checked = checked;
    return savedState;
  }

  @Override
  protected void onRestoreInstanceState(Parcelable state) {
    if (!(state instanceof SavedState)) {
      super.onRestoreInstanceState(state);
      return;
    }
    SavedState savedState = (SavedState) state;
    super.onRestoreInstanceState(savedState.getSuperState());
    setChecked(savedState.checked);
  }

  @Override
  protected void onDetachedFromWindow() {
    onFocusableChangedListener = null;
    super.onDetachedFromWindow();
  }

  /** Sets image button to be checkable or not. */
  public void setCheckable(boolean checkable) {
    if (this.checkable != checkable) {
      this.checkable = checkable;
      sendAccessibilityEvent(AccessibilityEventCompat.CONTENT_CHANGE_TYPE_UNDEFINED);
    }
  }

  /** Returns whether the image button is checkable. */
  public boolean isCheckable() {
    return checkable;
  }

  /** Sets image button to be pressable or not. */
  public void setPressable(boolean pressable) {
    this.pressable = pressable;
  }

  /** Returns whether the image button is pressable. */
  public boolean isPressable() {
    return pressable;
  }

  /** Register a callback to be invoked when the focusable state of this view changes. */
  public void setOnFocusableChangedListener(
      @Nullable OnFocusableChangedListener onFocusableChangedListener) {
    this.onFocusableChangedListener = onFocusableChangedListener;
  }

  /**
   * Interface definition for a callback to be invoked when the focusable state of this view
   * changes.
   */
  public interface OnFocusableChangedListener {
    /**
     * Called when the focusable state of a view has changed.
     *
     * @param view The view whose focusable state has changed.
     * @param focusable The new focusable state of view.
     */
    void onFocusableChanged(@NonNull View view, boolean focusable);
  }

  static class SavedState extends AbsSavedState {

    boolean checked;

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

    public SavedState(@NonNull Parcel source, ClassLoader loader) {
      super(source, loader);
      readFromParcel(source);
    }

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

    private void readFromParcel(@NonNull Parcel in) {
      checked = in.readInt() == 1;
    }

    public static final Creator<SavedState> CREATOR =
        new ClassLoaderCreator<SavedState>() {
          @NonNull
          @Override
          public SavedState createFromParcel(@NonNull Parcel in, ClassLoader loader) {
            return new SavedState(in, loader);
          }

          @NonNull
          @Override
          public SavedState createFromParcel(@NonNull Parcel in) {
            return new SavedState(in, null);
          }

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