Android Percentage Layout Height

I know that it is impossible to set percentages and that you can set a weight of certain images to scale their heights. What I am trying to do though is specify the height of a layout relative to the layout it is within. Basicly I have something like this

<LinearLayout android:layout_height="fill_parent">
  <LinearLayout>

  </LinearLayout>
</LinearLayout>

Of course this is a very simplified version, just so you can understand my gibberish. Basicly I want to set the inner line开发者_JAVA技巧arlayout to be around 50% of the main linearlayout.

What is the best way to do this?

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There is an attribute called android:weightSum.

You can set android:weightSum="2" in the parent linear_layout and android:weight="1" in the inner linear_layout.

Remember to set the inner linear_layout to fill_parent so weight attribute can work as expected.

Btw, I don't think its necesary to add a second view, altough I haven't tried. :)

<LinearLayout
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    android:weightSum="2">

    <LinearLayout
        android:layout_height="fill_parent"
        android:layout_width="fill_parent"
        android:layout_weight="1">
    </LinearLayout>

</LinearLayout>

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You could add another empty layout below that one and set them both to have the same layout weight. They should get 50% of the space each.

---

android:layout_weight=".YOURVALUE" is best way to implement in percentage

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/logTextBox"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight=".20"
        android:maxLines="500"
        android:scrollbars="vertical"
        android:singleLine="false"
        android:text="@string/logText" >
    </TextView>

</LinearLayout>

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Just as you said, I'd recommend weights. Percentages would be incredibly useful (don't know why they aren't supported), but one way you could do it is like so:

<LinearLayout
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    >
    <LinearLayout
        android:layout_height="0dp"
        android:layout_width="fill_parent"
        android:layout_weight="1"
        >
    </LinearLayout>
    <View
        android:layout_height="0dp"
        android:layout_width="fill_parent"
        android:layout_weight="1"
    />
</LinearLayout>

The takeaway being that you have an empty View that will take up the remaining space. Not ideal, but it does what you're looking for.

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With introduction of ContraintLayout, it's possible to implement with Guidelines:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.eugene.test1.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#AAA"
        android:text="TextView"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/guideline" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.5" />

</android.support.constraint.ConstraintLayout>

You can read more in this article Building interfaces with ConstraintLayout.

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You can add Constraint Layout 1.1 using this line in your android projects:

implementation 'com.android.support.constraint:constraint-layout:1.1.0'

In Constraint Layout 1.1 it’s been made simpler by allowing you to easily constrain any view to a percentage width or height.

If you want to set the height of the linearlayout to be around 50% of the main linearlayout , you can do it like this:

<LinearLayout android:layout_height="fill_parent">
  <LinearLayout
   app:layout_constraintHeight_percent="0.5">
  </LinearLayout>
</LinearLayout>