Android LinearLayout Tutorial
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LinearLayout is a ViewGroup that arranges the child View(s) in a single direction, either vertically or horizontally. You can specify its orientation by using the android:orientation attribute.
<!-- Horizontal LinearLayout (Default) -->
<LinearLayout
...
android:orientation="horizontal">
...
</LinearLayout>
<!-- Vertical LinearLayout -->
<LinearLayout
...
android:orientation="vertical">
...
</LinearLayout>
For example: Use Java code to create LinearLayout, and add child View(s) to LinearLayout:
// linearLayout = new LinearLayout(MainActivity.this);
// linearLayout.setOrientation(LinearLayout.HORIZONTAL);
LinearLayout.LayoutParams layoutParams
= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, 0);
Button button1 = new Button(this);
button1.setText("Button");
linearLayout.addView(button1, layoutParams);
Button button2 = new Button(this);
button2.setText("Long Button");
button2.setLayoutParams(layoutParams);
linearLayout.addView(button2);
android:layout_weight is an important attribute used for child View(s) of LinearLayout. It specifies how much space the child View(s) will take up in the parent View (LinearLayout) (horizontally or vertically). A layout_weight value greater than zero allows the child View to expand to fill any remaining space in the parent View. Child View(s) can be specified with a layout_weight value > 0, and then any remaining space in the parent View will be assigned to child View(s) according to their layout_weight ratio.
When all the child View(s) have android:layout_weight=0, you will see an empty space in the parent View (LinearLayout):
The child View(s) have android:layout_weight>0 will take up the free space of the parent View (LinearLayout):
The free space of the parent View (LinearLayout) will be allocated to the child View(s) in accordance with their layout_weight ratio.
The android:layout_weight attribute means the same thing in a vertical LinearLayout:
The android:layout_gravity attribute is applied to a child View to specify the relative position of the child View within the parent View (LinearLayout).
| Constant in Java | Value | Description |
| Gravity.LEFT | left | |
| Gravity.CENTER_HORIZONTAL | center_horizontal | |
| Gravity.RIGHT | right | |
| Gravity.TOP | top | |
| Gravity.CENTER_VERTICAL | center_vertical | |
| Gravity.BOTTOM | bottom | |
| Gravity.START | start | |
| Gravity.END | end | |
| Gravity.CENTER | center | |
Padding is the space in LinearLayout (inside the border), and surrounds 4 sides of the content.
You can set padding for LinearLayout by using the following attributes:
- android:padding
- android:paddingTop
- android:paddingRight
- android:paddingBottom
- android:paddingLeft
<LinearLayout
...
android:orientation="horizontal"
android:paddingTop="20dp"
android:paddingRight="30dp"
android:paddingBottom="10dp"
android:paddingLeft="20dp">
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
</LinearLayout>
Sometimes if you would like to set the space among the child View(s) of LinearLayout, there are several ways for you to handle this:
android:layout_margin
By applying the android:layout_margin attribute to all child View(s) of LinearLayout will help set the distance between them.
* layout_margin (Java code) *
// linearLayout = new LinearLayout(MainActivity.this);
// linearLayout.setOrientation(LinearLayout.HORIZONTAL);
LinearLayout.LayoutParams layoutParams
= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, 0);
layoutParams.setMargins(30, 20, 30, 0);
Button button1 = new Button(this);
button1.setText("Button");
linearLayout.addView(button1, layoutParams);
Button button2 = new Button(this);
button2.setText("Long Button");
button2.setLayoutParams(layoutParams);
linearLayout.addView(button2);
Space View
Android 4.0+ (API Level 14+) supports a new type of View called Space, which helps you add a free space to the interface. You can use Space to separate the child View(s) within LinearLayout.
<LinearLayout
...
android:layout_width="0dp"
android:layout_height="200dp"
android:background="#EFF6E7"
android:orientation="horizontal">
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
<Space
android:layout_width="10dp"
android:layout_height="wrap_content"
android:layout_weight="0" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Long Button" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
</LinearLayout>
* Add Space (Java code) *
// linearLayout = new LinearLayout(MainActivity.this);
// linearLayout.setOrientation(LinearLayout.HORIZONTAL);
LinearLayout.LayoutParams layoutParams
= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, 0);
LinearLayout.LayoutParams layoutParams2
= new LinearLayout.LayoutParams(15,
LinearLayout.LayoutParams.WRAP_CONTENT, 0);
Button button1 = new Button(this);
button1.setText("Button");
linearLayout.addView(button1, layoutParams);
// Create a Space View.
Space space = new Space(this);
space.setLayoutParams(layoutParams2);
linearLayout.addView(space);
Button button2 = new Button(this);
button2.setText("Long Button");
button2.setLayoutParams(layoutParams);
linearLayout.addView(button2);
android:divider
Android 3.0+ (API Level 11+) permits you to add a Divider between the two child View(s) in LinearLayout. Moreover, you can specify the style and color for the Divider.
* Divider *
<LinearLayout
...
android:orientation="horizontal">
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
<!-- Divider -->
<View
android:id="@+id/divider"
android:layout_width="15dp"
android:layout_height="match_parent"
android:layout_weight="0"
android:background="?android:attr/listDivider" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Long Button" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
</LinearLayout>
* Add Divider (Java code) *
// linearLayout = new LinearLayout(MainActivity.this);
// linearLayout.setOrientation(LinearLayout.HORIZONTAL);
LinearLayout.LayoutParams layoutParams
= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, 0);
LinearLayout.LayoutParams layoutParams2
= new LinearLayout.LayoutParams(15,
LinearLayout.LayoutParams.MATCH_PARENT, 0);
Button button1 = new Button(this);
button1.setText("Button");
linearLayout.addView(button1, layoutParams);
// Create a Divider.
View divider = new View(this);
// android:background="?android:attr/listDivider"
divider.setBackgroundResource(android.R.drawable.divider_horizontal_bright);
linearLayout.addView(divider, layoutParams2);
Button button2 = new Button(this);
button2.setText("Long Button");
button2.setLayoutParams(layoutParams);
linearLayout.addView(button2);
See more detailed article about Divider, it helps you customize Divider to suit your application:
- TODO Link?
