Android linear layout LinearLayout (7) and linearlayout

Android linear layout LinearLayout (7) and linearlayout

I. First, I want to know several attributes:

1. Layout

1) android: orientation = "vertical" vertical layout

2) android: orientation = "horizontal" horizontal layout

2. control content height and width Layout

1) android: layout_width = "match_parent", full of the screen. [Match parent window]

2) for android: layout_height = "wrap_content", the layout element will be changed based on the content. [The content includes]

3. layout Ratio

All views have a layout_weight value. The default value is zero, which means that the size of the view to be displayed occupies the size of the blank screen. If a value higher than zero is assigned, the free space in the parent view is split, the split size depends on the layout_weight value of each view and the ratio of the layout_weight value in the current screen layout to the layout_weight value in the screen layout of other views.

2. The following two examples are implemented:

1) Place the three buttons horizontally

  <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal" >        <Button            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="mc" />        <Button            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="m+" />        <Button            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="m-" />        <Button            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="mr" />    </LinearLayout>

Use layout_weight to make the three buttons occupy the same proportion.
2. Two buttons: three buttons at the first layer and two buttons at the second layer

<LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical" >                <LinearLayout            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="3"            android:orientation="horizontal" >            <Button                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:layout_weight="1"                android:text="1" />            <Button                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:layout_weight="1"                android:text="2" />            <Button                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:layout_weight="1"                android:text="3" />        </LinearLayout>                   <LinearLayout            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="3"            android:orientation="horizontal" >                              <Button                android:layout_width="0px"                android:layout_height="wrap_content"                android:layout_weight="2"                android:text="0" />            <Button                android:layout_width="0px"                android:layout_height="wrap_content"                android:layout_weight="1"                android:text="." />             </LinearLayout>    </LinearLayout>

First use a large layer and set the weight ratio to 3. The weight of the first button on the second layer accounts for 2/3 of the layer.