The weight (weight attribute) of LinearLayout_zhaojianand’s blog

Detailed explanation of weight (weight) attribute:

①The simplest usage:

As shown in the picture:

Implementation code:

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android  ="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" >
  <TextView
  android:layout_width="fill_parent"
  android:layout_height="0dp"
  android:background="#ADFF2F"
  android:text="weight is 1"
  android:layout_weight="1"/>
 
 
  <TextView
  android:layout_width="fill_parent"
  android:layout_height="0dp"
  android:background="#DA70D6"
  android:text="weight is 2"
  android:layout_weight="2"/>
 
 

 To achieve the first 1:1 effect, you only need to put the weight of the two LinearLayouts separately  Change it to 1 and 1. Usage summary: Divide the vertical direction according to the proportion: set the android:width attribute of the involved View to 0dp, and then set it to the android weight attribute to set the ratio; by analogy, for the horizontal direction, just  Set android:height to 0dp, and then set the weight attribute!  You can write a horizontal division of equal proportions to experience the simple usage!  
 ②Detailed explanation of weight attribute:
 Of course, if we do not apply the above-mentioned method of setting 0dp, use wrap_content and match_parent directly  , it is necessary to analyze the weight attribute, which is divided into two cases, wrap_content and match_parent!  In addition, it depends on whether the orientation of LinearLayout is horizontal or vertical, which determines which direction is divided in equal proportions
 1)wrap_content  It’s relatively simple, it’s directly proportional
  
 Implementation code:
<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android  ="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" >
  <TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:background="#ADFF2F"
  android:text="weight is 1"
  android:layout_weight="1"/>
 
 
  <TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:background="#DA70D6"
  android:text="weight is 2"
  android:layout_weight="2"/>
  <TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:background="#00ff66"
  android:text="weight is 3"
  android:layout_weight="3"/>
 
 

 2)match_parent  (fill_parent): This needs to be calculated
 We write this simple code:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/LinearLayout1"
     android:layout_width="match_parent"
     android:layout_heightfill_parent（match_parent）,But there is only one screen,Then1 - 3 = - 2 fill_parent 

 
step 2: The ratio is 1/6,2/6,3/6  span>
 
step 3: first come, first served,First giveone,calculate: 1 - 2 * (1/6) = 2/3 fill_parent Continue totwo,Calculation: 1 - 2 * (2  /6) = 1/3 fill_parent finallythree,calculate1 - 2 * (3/6) = 0 fill_parent 
 
step 4: So the final result is:onetakes two, twotakes one,threeThere is nothing. The above is whythreeThere is no reason for it,Maybe everyone is still a bit confused after reading it,It’s okay, Let’s give a few more examples and try it out!  
 
 The ratio is:  1:1:1
 
 
 
 
 According to the above calculation method, the result is: 1/3 1/3 1/3,  Yes
 
 Then we will  Try: 2:3:4
 
 
 
 
 Calculation result: 5/9 3/9 1/9, comparison effect diagram, 5:3:  1, that's right, so you can mark this calculation method!
 
 ③Set the weight attribute in the Java code:
 
setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
         LayoutParams.WRAP_CONTENT,   1));  

 0)">(LayoutParams.FILL_PARENT,

         LayoutParams.WRAP_CONTENT,   1));