ForegroundLinearLayout.java revision 8e10080c914d1ad0784394fa3026b85535535847 
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.annotation.TargetApi;
22import android.content.Context;
23import android.content.res.TypedArray;
24import android.graphics.Canvas;
25import android.graphics.Rect;
26import android.graphics.drawable.Drawable;
27import android.support.annotation.NonNull;
28import android.support.annotation.RequiresApi;
29import android.support.annotation.RestrictTo;
30import android.support.design.R;
31import android.support.v7.widget.LinearLayoutCompat;
32import android.util.AttributeSet;
33import android.view.Gravity;
34
35/**
36 * @hide
37 */
38@RestrictTo(LIBRARY_GROUP)
39public class ForegroundLinearLayout extends LinearLayoutCompat {
40
41    private Drawable mForeground;
42
43    private final Rect mSelfBounds = new Rect();
44
45    private final Rect mOverlayBounds = new Rect();
46
47    private int mForegroundGravity = Gravity.FILL;
48
49    protected boolean mForegroundInPadding = true;
50
51    boolean mForegroundBoundsChanged = false;
52
53    public ForegroundLinearLayout(Context context) {
54        this(context, null);
55    }
56
57    public ForegroundLinearLayout(Context context, AttributeSet attrs) {
58        this(context, attrs, 0);
59    }
60
61    public ForegroundLinearLayout(Context context, AttributeSet attrs, int defStyle) {
62        super(context, attrs, defStyle);
63
64        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ForegroundLinearLayout,
65                defStyle, 0);
66
67        mForegroundGravity = a.getInt(
68                R.styleable.ForegroundLinearLayout_android_foregroundGravity, mForegroundGravity);
69
70        final Drawable d = a.getDrawable(R.styleable.ForegroundLinearLayout_android_foreground);
71        if (d != null) {
72            setForeground(d);
73        }
74
75        mForegroundInPadding = a.getBoolean(
76                R.styleable.ForegroundLinearLayout_foregroundInsidePadding, true);
77
78        a.recycle();
79    }
80
81    /**
82     * Describes how the foreground is positioned.
83     *
84     * @return foreground gravity.
85     * @see #setForegroundGravity(int)
86     */
87    public int getForegroundGravity() {
88        return mForegroundGravity;
89    }
90
91    /**
92     * Describes how the foreground is positioned. Defaults to START and TOP.
93     *
94     * @param foregroundGravity See {@link android.view.Gravity}
95     * @see #getForegroundGravity()
96     */
97    public void setForegroundGravity(int foregroundGravity) {
98        if (mForegroundGravity != foregroundGravity) {
99            if ((foregroundGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
100                foregroundGravity |= Gravity.START;
101            }
102
103            if ((foregroundGravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
104                foregroundGravity |= Gravity.TOP;
105            }
106
107            mForegroundGravity = foregroundGravity;
108
109            if (mForegroundGravity == Gravity.FILL && mForeground != null) {
110                Rect padding = new Rect();
111                mForeground.getPadding(padding);
112            }
113
114            requestLayout();
115        }
116    }
117
118    @Override
119    protected boolean verifyDrawable(Drawable who) {
120        return super.verifyDrawable(who) || (who == mForeground);
121    }
122
123    @RequiresApi(11)
124    @TargetApi(11)
125    @Override
126    public void jumpDrawablesToCurrentState() {
127        super.jumpDrawablesToCurrentState();
128        if (mForeground != null) {
129            mForeground.jumpToCurrentState();
130        }
131    }
132
133    @Override
134    protected void drawableStateChanged() {
135        super.drawableStateChanged();
136        if (mForeground != null && mForeground.isStateful()) {
137            mForeground.setState(getDrawableState());
138        }
139    }
140
141    /**
142     * Supply a Drawable that is to be rendered on top of all of the child
143     * views in the frame layout.  Any padding in the Drawable will be taken
144     * into account by ensuring that the children are inset to be placed
145     * inside of the padding area.
146     *
147     * @param drawable The Drawable to be drawn on top of the children.
148     */
149    public void setForeground(Drawable drawable) {
150        if (mForeground != drawable) {
151            if (mForeground != null) {
152                mForeground.setCallback(null);
153                unscheduleDrawable(mForeground);
154            }
155
156            mForeground = drawable;
157
158            if (drawable != null) {
159                setWillNotDraw(false);
160                drawable.setCallback(this);
161                if (drawable.isStateful()) {
162                    drawable.setState(getDrawableState());
163                }
164                if (mForegroundGravity == Gravity.FILL) {
165                    Rect padding = new Rect();
166                    drawable.getPadding(padding);
167                }
168            } else {
169                setWillNotDraw(true);
170            }
171            requestLayout();
172            invalidate();
173        }
174    }
175
176    /**
177     * Returns the drawable used as the foreground of this FrameLayout. The
178     * foreground drawable, if non-null, is always drawn on top of the children.
179     *
180     * @return A Drawable or null if no foreground was set.
181     */
182    public Drawable getForeground() {
183        return mForeground;
184    }
185
186    @Override
187    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
188        super.onLayout(changed, left, top, right, bottom);
189        mForegroundBoundsChanged |= changed;
190    }
191
192    @Override
193    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
194        super.onSizeChanged(w, h, oldw, oldh);
195        mForegroundBoundsChanged = true;
196    }
197
198    @Override
199    public void draw(@NonNull Canvas canvas) {
200        super.draw(canvas);
201
202        if (mForeground != null) {
203            final Drawable foreground = mForeground;
204
205            if (mForegroundBoundsChanged) {
206                mForegroundBoundsChanged = false;
207                final Rect selfBounds = mSelfBounds;
208                final Rect overlayBounds = mOverlayBounds;
209
210                final int w = getRight() - getLeft();
211                final int h = getBottom() - getTop();
212
213                if (mForegroundInPadding) {
214                    selfBounds.set(0, 0, w, h);
215                } else {
216                    selfBounds.set(getPaddingLeft(), getPaddingTop(),
217                            w - getPaddingRight(), h - getPaddingBottom());
218                }
219
220                Gravity.apply(mForegroundGravity, foreground.getIntrinsicWidth(),
221                        foreground.getIntrinsicHeight(), selfBounds, overlayBounds);
222                foreground.setBounds(overlayBounds);
223            }
224
225            foreground.draw(canvas);
226        }
227    }
228
229    @RequiresApi(21)
230    @TargetApi(21)
231    @Override
232    public void drawableHotspotChanged(float x, float y) {
233        super.drawableHotspotChanged(x, y);
234        if (mForeground != null) {
235            mForeground.setHotspot(x, y);
236        }
237    }
238
239}
240