1 /*
2  * Copyright (C) 2011 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 
17 package android.widget;
18 
19 import android.content.Context;
20 import android.graphics.Canvas;
21 import android.util.AttributeSet;
22 import android.view.View;
23 
24 /**
25  * Space is a lightweight View subclass that may be used to create gaps between components
26  * in general purpose layouts.
27  */
28 public final class Space extends View {
29     /**
30      * {@inheritDoc}
31      */
Space(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)32     public Space(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
33         super(context, attrs, defStyleAttr, defStyleRes);
34         if (getVisibility() == VISIBLE) {
35             setVisibility(INVISIBLE);
36         }
37     }
38 
39     /**
40      * {@inheritDoc}
41      */
Space(Context context, AttributeSet attrs, int defStyleAttr)42     public Space(Context context, AttributeSet attrs, int defStyleAttr) {
43         this(context, attrs, defStyleAttr, 0);
44     }
45 
46     /**
47      * {@inheritDoc}
48      */
Space(Context context, AttributeSet attrs)49     public Space(Context context, AttributeSet attrs) {
50         this(context, attrs, 0);
51     }
52 
53     /**
54      * {@inheritDoc}
55      */
Space(Context context)56     public Space(Context context) {
57         //noinspection NullableProblems
58         this(context, null);
59     }
60 
61     /**
62      * Draw nothing.
63      *
64      * @param canvas an unused parameter.
65      */
66     @Override
draw(Canvas canvas)67     public void draw(Canvas canvas) {
68     }
69 
70     /**
71      * Compare to: {@link View#getDefaultSize(int, int)}
72      * If mode is AT_MOST, return the child size instead of the parent size
73      * (unless it is too big).
74      */
getDefaultSize2(int size, int measureSpec)75     private static int getDefaultSize2(int size, int measureSpec) {
76         int result = size;
77         int specMode = MeasureSpec.getMode(measureSpec);
78         int specSize = MeasureSpec.getSize(measureSpec);
79 
80         switch (specMode) {
81             case MeasureSpec.UNSPECIFIED:
82                 result = size;
83                 break;
84             case MeasureSpec.AT_MOST:
85                 result = Math.min(size, specSize);
86                 break;
87             case MeasureSpec.EXACTLY:
88                 result = specSize;
89                 break;
90         }
91         return result;
92     }
93 
94     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)95     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
96         setMeasuredDimension(
97                 getDefaultSize2(getSuggestedMinimumWidth(), widthMeasureSpec),
98                 getDefaultSize2(getSuggestedMinimumHeight(), heightMeasureSpec));
99     }
100 }
101