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