1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.support.v7.internal.widget;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.graphics.Canvas;
22import android.support.v7.appcompat.R;
23import android.util.AttributeSet;
24import android.view.LayoutInflater;
25import android.view.View;
26import android.view.ViewGroup;
27import android.view.ViewParent;
28
29
30import java.lang.ref.WeakReference;
31
32/**
33 * Backport of {@link android.view.ViewStub} so that we can set the
34 * {@link android.view.LayoutInflater} on devices before Jelly Bean.
35 *
36 * @hide
37 */
38public final class ViewStubCompat extends View {
39    private int mLayoutResource = 0;
40    private int mInflatedId;
41
42    private WeakReference<View> mInflatedViewRef;
43
44    private LayoutInflater mInflater;
45    private OnInflateListener mInflateListener;
46
47    public ViewStubCompat(Context context, AttributeSet attrs) {
48        this(context, attrs, 0);
49    }
50
51    public ViewStubCompat(Context context, AttributeSet attrs, int defStyle) {
52        super(context, attrs, defStyle);
53
54        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ViewStubCompat,
55                defStyle, 0);
56
57        mInflatedId = a.getResourceId(R.styleable.ViewStubCompat_android_inflatedId, NO_ID);
58        mLayoutResource = a.getResourceId(R.styleable.ViewStubCompat_android_layout, 0);
59
60        setId(a.getResourceId(R.styleable.ViewStubCompat_android_id, NO_ID));
61        a.recycle();
62
63        setVisibility(GONE);
64        setWillNotDraw(true);
65    }
66
67    /**
68     * Returns the id taken by the inflated view. If the inflated id is
69     * {@link View#NO_ID}, the inflated view keeps its original id.
70     *
71     * @return A positive integer used to identify the inflated view or
72     *         {@link #NO_ID} if the inflated view should keep its id.
73     *
74     * @see #setInflatedId(int)
75     * @attr ref android.R.styleable#ViewStub_inflatedId
76     */
77    public int getInflatedId() {
78        return mInflatedId;
79    }
80
81    /**
82     * Defines the id taken by the inflated view. If the inflated id is
83     * {@link View#NO_ID}, the inflated view keeps its original id.
84     *
85     * @param inflatedId A positive integer used to identify the inflated view or
86     *                   {@link #NO_ID} if the inflated view should keep its id.
87     *
88     * @see #getInflatedId()
89     * @attr ref android.R.styleable#ViewStub_inflatedId
90     */
91    public void setInflatedId(int inflatedId) {
92        mInflatedId = inflatedId;
93    }
94
95    /**
96     * Returns the layout resource that will be used by {@link #setVisibility(int)} or
97     * {@link #inflate()} to replace this StubbedView
98     * in its parent by another view.
99     *
100     * @return The layout resource identifier used to inflate the new View.
101     *
102     * @see #setLayoutResource(int)
103     * @see #setVisibility(int)
104     * @see #inflate()
105     * @attr ref android.R.styleable#ViewStub_layout
106     */
107    public int getLayoutResource() {
108        return mLayoutResource;
109    }
110
111    /**
112     * Specifies the layout resource to inflate when this StubbedView becomes visible or invisible
113     * or when {@link #inflate()} is invoked. The View created by inflating the layout resource is
114     * used to replace this StubbedView in its parent.
115     *
116     * @param layoutResource A valid layout resource identifier (different from 0.)
117     *
118     * @see #getLayoutResource()
119     * @see #setVisibility(int)
120     * @see #inflate()
121     * @attr ref android.R.styleable#ViewStub_layout
122     */
123    public void setLayoutResource(int layoutResource) {
124        mLayoutResource = layoutResource;
125    }
126
127    /**
128     * Set {@link LayoutInflater} to use in {@link #inflate()}, or {@code null}
129     * to use the default.
130     */
131    public void setLayoutInflater(LayoutInflater inflater) {
132        mInflater = inflater;
133    }
134
135    /**
136     * Get current {@link LayoutInflater} used in {@link #inflate()}.
137     */
138    public LayoutInflater getLayoutInflater() {
139        return mInflater;
140    }
141
142    @Override
143    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
144        setMeasuredDimension(0, 0);
145    }
146
147    @Override
148    public void draw(Canvas canvas) {
149    }
150
151    @Override
152    protected void dispatchDraw(Canvas canvas) {
153    }
154
155    /**
156     * When visibility is set to {@link #VISIBLE} or {@link #INVISIBLE},
157     * {@link #inflate()} is invoked and this StubbedView is replaced in its parent
158     * by the inflated layout resource. After that calls to this function are passed
159     * through to the inflated view.
160     *
161     * @param visibility One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
162     *
163     * @see #inflate()
164     */
165    @Override
166    public void setVisibility(int visibility) {
167        if (mInflatedViewRef != null) {
168            View view = mInflatedViewRef.get();
169            if (view != null) {
170                view.setVisibility(visibility);
171            } else {
172                throw new IllegalStateException("setVisibility called on un-referenced view");
173            }
174        } else {
175            super.setVisibility(visibility);
176            if (visibility == VISIBLE || visibility == INVISIBLE) {
177                inflate();
178            }
179        }
180    }
181
182    /**
183     * Inflates the layout resource identified by {@link #getLayoutResource()}
184     * and replaces this StubbedView in its parent by the inflated layout resource.
185     *
186     * @return The inflated layout resource.
187     *
188     */
189    public View inflate() {
190        final ViewParent viewParent = getParent();
191
192        if (viewParent != null && viewParent instanceof ViewGroup) {
193            if (mLayoutResource != 0) {
194                final ViewGroup parent = (ViewGroup) viewParent;
195                final LayoutInflater factory;
196                if (mInflater != null) {
197                    factory = mInflater;
198                } else {
199                    factory = LayoutInflater.from(getContext());
200                }
201                final View view = factory.inflate(mLayoutResource, parent,
202                        false);
203
204                if (mInflatedId != NO_ID) {
205                    view.setId(mInflatedId);
206                }
207
208                final int index = parent.indexOfChild(this);
209                parent.removeViewInLayout(this);
210
211                final ViewGroup.LayoutParams layoutParams = getLayoutParams();
212                if (layoutParams != null) {
213                    parent.addView(view, index, layoutParams);
214                } else {
215                    parent.addView(view, index);
216                }
217
218                mInflatedViewRef = new WeakReference<View>(view);
219
220                if (mInflateListener != null) {
221                    mInflateListener.onInflate(this, view);
222                }
223
224                return view;
225            } else {
226                throw new IllegalArgumentException("ViewStub must have a valid layoutResource");
227            }
228        } else {
229            throw new IllegalStateException("ViewStub must have a non-null ViewGroup viewParent");
230        }
231    }
232
233    /**
234     * Specifies the inflate listener to be notified after this ViewStub successfully
235     * inflated its layout resource.
236     *
237     * @param inflateListener The OnInflateListener to notify of successful inflation.
238     *
239     * @see android.view.ViewStub.OnInflateListener
240     */
241    public void setOnInflateListener(OnInflateListener inflateListener) {
242        mInflateListener = inflateListener;
243    }
244
245    /**
246     * Listener used to receive a notification after a ViewStub has successfully
247     * inflated its layout resource.
248     *
249     * @see android.view.ViewStub#setOnInflateListener(android.view.ViewStub.OnInflateListener)
250     */
251    public static interface OnInflateListener {
252        /**
253         * Invoked after a ViewStub successfully inflated its layout resource.
254         * This method is invoked after the inflated view was added to the
255         * hierarchy but before the layout pass.
256         *
257         * @param stub The ViewStub that initiated the inflation.
258         * @param inflated The inflated View.
259         */
260        void onInflate(ViewStubCompat stub, View inflated);
261    }
262}