ForegroundLinearLayout.java revision c39d9c75590eca86a5e7e32a8824ba04a0d42e9b 
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 android.content.Context;
20import android.content.res.TypedArray;
21import android.graphics.Canvas;
22import android.graphics.Rect;
23import android.graphics.drawable.Drawable;
24import android.support.annotation.NonNull;
25import android.support.annotation.RestrictTo;
26import android.support.design.R;
27import android.support.v7.widget.LinearLayoutCompat;
28import android.util.AttributeSet;
29import android.view.Gravity;
30
31import static android.support.annotation.RestrictTo.Scope.GROUP_ID;
32
33/**
34 * @hide
35 */
36@RestrictTo(GROUP_ID)
37public class ForegroundLinearLayout extends LinearLayoutCompat {
38
39    private Drawable mForeground;
40
41    private final Rect mSelfBounds = new Rect();
42
43    private final Rect mOverlayBounds = new Rect();
44
45    private int mForegroundGravity = Gravity.FILL;
46
47    protected boolean mForegroundInPadding = true;
48
49    boolean mForegroundBoundsChanged = false;
50
51    public ForegroundLinearLayout(Context context) {
52        this(context, null);
53    }
54
55    public ForegroundLinearLayout(Context context, AttributeSet attrs) {
56        this(context, attrs, 0);
57    }
58
59    public ForegroundLinearLayout(Context context, AttributeSet attrs, int defStyle) {
60        super(context, attrs, defStyle);
61
62        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ForegroundLinearLayout,
63                defStyle, 0);
64
65        mForegroundGravity = a.getInt(
66                R.styleable.ForegroundLinearLayout_android_foregroundGravity, mForegroundGravity);
67
68        final Drawable d = a.getDrawable(R.styleable.ForegroundLinearLayout_android_foreground);
69        if (d != null) {
70            setForeground(d);
71        }
72
73        mForegroundInPadding = a.getBoolean(
74                R.styleable.ForegroundLinearLayout_foregroundInsidePadding, true);
75
76        a.recycle();
77    }
78
79    /**
80     * Describes how the foreground is positioned.
81     *
82     * @return foreground gravity.
83     * @see #setForegroundGravity(int)
84     */
85    public int getForegroundGravity() {
86        return mForegroundGravity;
87    }
88
89    /**
90     * Describes how the foreground is positioned. Defaults to START and TOP.
91     *
92     * @param foregroundGravity See {@link android.view.Gravity}
93     * @see #getForegroundGravity()
94     */
95    public void setForegroundGravity(int foregroundGravity) {
96        if (mForegroundGravity != foregroundGravity) {
97            if ((foregroundGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
98                foregroundGravity |= Gravity.START;
99            }
100
101            if ((foregroundGravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
102                foregroundGravity |= Gravity.TOP;
103            }
104
105            mForegroundGravity = foregroundGravity;
106
107            if (mForegroundGravity == Gravity.FILL && mForeground != null) {
108                Rect padding = new Rect();
109                mForeground.getPadding(padding);
110            }
111
112            requestLayout();
113        }
114    }
115
116    @Override
117    protected boolean verifyDrawable(Drawable who) {
118        return super.verifyDrawable(who) || (who == mForeground);
119    }
120
121    @Override
122    public void jumpDrawablesToCurrentState() {
123        super.jumpDrawablesToCurrentState();
124        if (mForeground != null) {
125            mForeground.jumpToCurrentState();
126        }
127    }
128
129    @Override
130    protected void drawableStateChanged() {
131        super.drawableStateChanged();
132        if (mForeground != null && mForeground.isStateful()) {
133            mForeground.setState(getDrawableState());
134        }
135    }
136
137    /**
138     * Supply a Drawable that is to be rendered on top of all of the child
139     * views in the frame layout.  Any padding in the Drawable will be taken
140     * into account by ensuring that the children are inset to be placed
141     * inside of the padding area.
142     *
143     * @param drawable The Drawable to be drawn on top of the children.
144     */
145    public void setForeground(Drawable drawable) {
146        if (mForeground != drawable) {
147            if (mForeground != null) {
148                mForeground.setCallback(null);
149                unscheduleDrawable(mForeground);
150            }
151
152            mForeground = drawable;
153
154            if (drawable != null) {
155                setWillNotDraw(false);
156                drawable.setCallback(this);
157                if (drawable.isStateful()) {
158                    drawable.setState(getDrawableState());
159                }
160                if (mForegroundGravity == Gravity.FILL) {
161                    Rect padding = new Rect();
162                    drawable.getPadding(padding);
163                }
164            } else {
165                setWillNotDraw(true);
166            }
167            requestLayout();
168            invalidate();
169        }
170    }
171
172    /**
173     * Returns the drawable used as the foreground of this FrameLayout. The
174     * foreground drawable, if non-null, is always drawn on top of the children.
175     *
176     * @return A Drawable or null if no foreground was set.
177     */
178    public Drawable getForeground() {
179        return mForeground;
180    }
181
182    @Override
183    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
184        super.onLayout(changed, left, top, right, bottom);
185        mForegroundBoundsChanged |= changed;
186    }
187
188    @Override
189    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
190        super.onSizeChanged(w, h, oldw, oldh);
191        mForegroundBoundsChanged = true;
192    }
193
194    @Override
195    public void draw(@NonNull Canvas canvas) {
196        super.draw(canvas);
197
198        if (mForeground != null) {
199            final Drawable foreground = mForeground;
200
201            if (mForegroundBoundsChanged) {
202                mForegroundBoundsChanged = false;
203                final Rect selfBounds = mSelfBounds;
204                final Rect overlayBounds = mOverlayBounds;
205
206                final int w = getRight() - getLeft();
207                final int h = getBottom() - getTop();
208
209                if (mForegroundInPadding) {
210                    selfBounds.set(0, 0, w, h);
211                } else {
212                    selfBounds.set(getPaddingLeft(), getPaddingTop(),
213                            w - getPaddingRight(), h - getPaddingBottom());
214                }
215
216                Gravity.apply(mForegroundGravity, foreground.getIntrinsicWidth(),
217                        foreground.getIntrinsicHeight(), selfBounds, overlayBounds);
218                foreground.setBounds(overlayBounds);
219            }
220
221            foreground.draw(canvas);
222        }
223    }
224
225    @Override
226    public void drawableHotspotChanged(float x, float y) {
227        super.drawableHotspotChanged(x, y);
228        if (mForeground != null) {
229            mForeground.setHotspot(x, y);
230        }
231    }
232
233}
234