ForegroundLinearLayout.java revision e22ae93397361d1bd5568fa51d82e2f7553712e1 
1/*
2 * Copyright (C) 2015 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.design.internal;
18
19import static android.support.annotation.RestrictTo.Scope.LIBRARY_GROUP;
20
21import android.content.Context;
22import android.content.res.TypedArray;
23import android.graphics.Canvas;
24import android.graphics.Rect;
25import android.graphics.drawable.Drawable;
26import android.support.annotation.NonNull;
27import android.support.annotation.RequiresApi;
28import android.support.annotation.RestrictTo;
29import android.support.design.R;
30import android.support.v7.widget.LinearLayoutCompat;
31import android.util.AttributeSet;
32import android.view.Gravity;
33
34/**
35 * @hide
36 */
37@RestrictTo(LIBRARY_GROUP)
38public class ForegroundLinearLayout extends LinearLayoutCompat {
39
40    private Drawable mForeground;
41
42    private final Rect mSelfBounds = new Rect();
43
44    private final Rect mOverlayBounds = new Rect();
45
46    private int mForegroundGravity = Gravity.FILL;
47
48    protected boolean mForegroundInPadding = true;
49
50    boolean mForegroundBoundsChanged = false;
51
52    public ForegroundLinearLayout(Context context) {
53        this(context, null);
54    }
55
56    public ForegroundLinearLayout(Context context, AttributeSet attrs) {
57        this(context, attrs, 0);
58    }
59
60    public ForegroundLinearLayout(Context context, AttributeSet attrs, int defStyle) {
61        super(context, attrs, defStyle);
62
63        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ForegroundLinearLayout,
64                defStyle, 0);
65
66        mForegroundGravity = a.getInt(
67                R.styleable.ForegroundLinearLayout_android_foregroundGravity, mForegroundGravity);
68
69        final Drawable d = a.getDrawable(R.styleable.ForegroundLinearLayout_android_foreground);
70        if (d != null) {
71            setForeground(d);
72        }
73
74        mForegroundInPadding = a.getBoolean(
75                R.styleable.ForegroundLinearLayout_foregroundInsidePadding, true);
76
77        a.recycle();
78    }
79
80    /**
81     * Describes how the foreground is positioned.
82     *
83     * @return foreground gravity.
84     * @see #setForegroundGravity(int)
85     */
86    public int getForegroundGravity() {
87        return mForegroundGravity;
88    }
89
90    /**
91     * Describes how the foreground is positioned. Defaults to START and TOP.
92     *
93     * @param foregroundGravity See {@link android.view.Gravity}
94     * @see #getForegroundGravity()
95     */
96    public void setForegroundGravity(int foregroundGravity) {
97        if (mForegroundGravity != foregroundGravity) {
98            if ((foregroundGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
99                foregroundGravity |= Gravity.START;
100            }
101
102            if ((foregroundGravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
103                foregroundGravity |= Gravity.TOP;
104            }
105
106            mForegroundGravity = foregroundGravity;
107
108            if (mForegroundGravity == Gravity.FILL && mForeground != null) {
109                Rect padding = new Rect();
110                mForeground.getPadding(padding);
111            }
112
113            requestLayout();
114        }
115    }
116
117    @Override
118    protected boolean verifyDrawable(Drawable who) {
119        return super.verifyDrawable(who) || (who == mForeground);
120    }
121
122    @RequiresApi(11)
123    @Override
124    public void jumpDrawablesToCurrentState() {
125        super.jumpDrawablesToCurrentState();
126        if (mForeground != null) {
127            mForeground.jumpToCurrentState();
128        }
129    }
130
131    @Override
132    protected void drawableStateChanged() {
133        super.drawableStateChanged();
134        if (mForeground != null && mForeground.isStateful()) {
135            mForeground.setState(getDrawableState());
136        }
137    }
138
139    /**
140     * Supply a Drawable that is to be rendered on top of all of the child
141     * views in the frame layout.  Any padding in the Drawable will be taken
142     * into account by ensuring that the children are inset to be placed
143     * inside of the padding area.
144     *
145     * @param drawable The Drawable to be drawn on top of the children.
146     */
147    public void setForeground(Drawable drawable) {
148        if (mForeground != drawable) {
149            if (mForeground != null) {
150                mForeground.setCallback(null);
151                unscheduleDrawable(mForeground);
152            }
153
154            mForeground = drawable;
155
156            if (drawable != null) {
157                setWillNotDraw(false);
158                drawable.setCallback(this);
159                if (drawable.isStateful()) {
160                    drawable.setState(getDrawableState());
161                }
162                if (mForegroundGravity == Gravity.FILL) {
163                    Rect padding = new Rect();
164                    drawable.getPadding(padding);
165                }
166            } else {
167                setWillNotDraw(true);
168            }
169            requestLayout();
170            invalidate();
171        }
172    }
173
174    /**
175     * Returns the drawable used as the foreground of this FrameLayout. The
176     * foreground drawable, if non-null, is always drawn on top of the children.
177     *
178     * @return A Drawable or null if no foreground was set.
179     */
180    public Drawable getForeground() {
181        return mForeground;
182    }
183
184    @Override
185    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
186        super.onLayout(changed, left, top, right, bottom);
187        mForegroundBoundsChanged |= changed;
188    }
189
190    @Override
191    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
192        super.onSizeChanged(w, h, oldw, oldh);
193        mForegroundBoundsChanged = true;
194    }
195
196    @Override
197    public void draw(@NonNull Canvas canvas) {
198        super.draw(canvas);
199
200        if (mForeground != null) {
201            final Drawable foreground = mForeground;
202
203            if (mForegroundBoundsChanged) {
204                mForegroundBoundsChanged = false;
205                final Rect selfBounds = mSelfBounds;
206                final Rect overlayBounds = mOverlayBounds;
207
208                final int w = getRight() - getLeft();
209                final int h = getBottom() - getTop();
210
211                if (mForegroundInPadding) {
212                    selfBounds.set(0, 0, w, h);
213                } else {
214                    selfBounds.set(getPaddingLeft(), getPaddingTop(),
215                            w - getPaddingRight(), h - getPaddingBottom());
216                }
217
218                Gravity.apply(mForegroundGravity, foreground.getIntrinsicWidth(),
219                        foreground.getIntrinsicHeight(), selfBounds, overlayBounds);
220                foreground.setBounds(overlayBounds);
221            }
222
223            foreground.draw(canvas);
224        }
225    }
226
227    @RequiresApi(21)
228    @Override
229    public void drawableHotspotChanged(float x, float y) {
230        super.drawableHotspotChanged(x, y);
231        if (mForeground != null) {
232            mForeground.setHotspot(x, y);
233        }
234    }
235
236}
237