Java tutorial
/* * 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 android.support.design.widget; import android.content.Context; import android.support.annotation.RestrictTo; import android.support.v4.view.AccessibilityDelegateCompat; import android.support.v4.view.ViewCompat; import android.support.v4.view.accessibility.AccessibilityEventCompat; import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; import android.support.v7.widget.AppCompatImageButton; import android.util.AttributeSet; import android.view.View; import android.view.accessibility.AccessibilityEvent; import android.widget.Checkable; import static android.support.annotation.RestrictTo.Scope.LIBRARY_GROUP; /** * @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 mChecked; public CheckableImageButton(Context context) { this(context, null); } public CheckableImageButton(Context context, AttributeSet attrs) { this(context, attrs, android.support.v7.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, AccessibilityEvent event) { super.onInitializeAccessibilityEvent(host, event); event.setChecked(isChecked()); } @Override public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) { super.onInitializeAccessibilityNodeInfo(host, info); info.setCheckable(true); info.setChecked(isChecked()); } }); } @Override public void setChecked(boolean checked) { if (mChecked != checked) { mChecked = checked; refreshDrawableState(); sendAccessibilityEvent(AccessibilityEventCompat.TYPE_WINDOW_CONTENT_CHANGED); } } @Override public boolean isChecked() { return mChecked; } @Override public void toggle() { setChecked(!mChecked); } @Override public int[] onCreateDrawableState(int extraSpace) { if (mChecked) { return mergeDrawableStates(super.onCreateDrawableState(extraSpace + DRAWABLE_STATE_CHECKED.length), DRAWABLE_STATE_CHECKED); } else { return super.onCreateDrawableState(extraSpace); } } }