Android: Align LinearLayout center for all screen sizes

问题

I want to design a layout for my login screen, I tried the following codes. Using some hardcoded values I got my center green color layout center for some screen sizes. I know using hardcoded values wont work on different screen sizes. I tried numerous stuffs on SO. Please provide me the best way

<?xml version="1.0" encoding="utf-8"?>

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/background" >

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/register_header"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/title_image"
            android:layout_width="wrap_content"
            android:layout_height="40dp"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:layout_marginBottom="5dp"
            android:layout_marginTop="5dp"
            android:gravity="center"
            android:src="@drawable/logo_blue" />


    </RelativeLayout>

    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
         android:layout_marginLeft="150dp"
        android:layout_marginRight="150dp"
        android:layout_marginTop="50dp"
        android:layout_marginBottom="50dp"
        android:orientation="vertical" >

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/UserInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/WelcomeInfo"
            android:gravity="center_vertical"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/user"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="User Name"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/username"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enter username"
                android:singleLine="true"
                android:textColor="#000000" >
            </EditText>
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/PassInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/UserInfo"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/pwd"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Password"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/password"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enterpassword"
                android:singleLine="true"
                android:textColor="#000000" />
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/StoreNumInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/WelcomeInfo"
            android:gravity="center_vertical"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/num"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Store Number"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/store_num"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enter the Store number"
                android:imeOptions="actionDone"
                  android:password="true"

                android:textColor="#000000" >
            </EditText>
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/Options"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/PassInfo"
            android:orientation="horizontal" >

            <CheckBox
                android:id="@+id/signed_in"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Stay Signed-in"
                android:textColor="#000000" />


            <Button
                android:id="@+id/login"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Login"
                android:textSize="28dp"
                android:textStyle="bold" />
        </LinearLayout>


    </LinearLayout>
</LinearLayout> </ScrollView>

---

回答1:

Use your cover of your green layout as RelativeLayout. and then define your greenLayout like this. android:layout_centerHorizontal="true" android:layout_centerVertical="true"

Look at my xml it can center all screen

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

<LinearLayout
    android:id="@+id/lin_all"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:orientation="vertical" >
</LinearLayout>

</RelativeLayout>

回答2:

Try this:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical" >

// put all your xml code here


    </LinearLayout>

Try the edited Code:

NEW EDIT:

<?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:gravity="center"
    android:orientation="vertical" 
    android:weightSum="1">


   <RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/register_header"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="0.1"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/title_image"
            android:layout_width="wrap_content"
            android:layout_height="0dp"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:layout_marginBottom="5dp"
            android:layout_marginTop="5dp"
            android:gravity="center"
            android:src="@drawable/logo_blue"  />


    </RelativeLayout>

    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:layout_weight="0.9"
        android:gravity="center"
        android:orientation="vertical" >

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/UserInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/WelcomeInfo"
            android:gravity="center_vertical"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/user"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="User Name"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/username"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enter username"
                android:singleLine="true"
                android:textColor="#000000" >
            </EditText>
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/PassInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/UserInfo"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/pwd"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Password"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/password"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enterpassword"
                android:singleLine="true"
                android:textColor="#000000" />
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/StoreNumInfo"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/WelcomeInfo"
            android:gravity="center_vertical"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/num"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Store Number"
                android:textColor="#000000"
                android:textSize="10pt"
                android:textStyle="bold" />

            <EditText
                android:id="@+id/store_num"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:hint="Enter the Store number"
                android:imeOptions="actionDone"
                  android:password="true"

                android:textColor="#000000" >
            </EditText>
        </LinearLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/Options"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/PassInfo"
            android:orientation="horizontal" >

            <CheckBox
                android:id="@+id/signed_in"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Stay Signed-in"
                android:textColor="#000000" />


            <Button
                android:id="@+id/login"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="1"
                android:text="Login"
                android:textSize="28dp"
                android:textStyle="bold" />
        </LinearLayout>


    </LinearLayout>
</LinearLayout>

回答3:

to work in different screen sizes i suggest you to create different xml files based on screen sizes........you can look at it here http://developer.android.com/guide/practices/screens_support.html...

回答4:

Try this XML code, it will solve youyr problem.

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

    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:orientation="vertical" >

        <RelativeLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/register_header"
            android:layout_width="fill_parent"
            android:layout_height="50dp"
            android:orientation="horizontal" >

            <ImageView
                android:id="@+id/title_image"
                android:layout_width="wrap_content"
                android:layout_height="40dp"
                android:layout_centerHorizontal="true"
                android:layout_centerVertical="true"
                android:layout_marginBottom="5dp"
                android:layout_marginTop="5dp"
                android:gravity="center"
                android:src="@drawable/ic_launcher" />
        </RelativeLayout>

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <LinearLayout
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/UserInfo"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal" >

                <TextView
                    android:id="@+id/user"
                    android:layout_width="match_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:text="User Name"
                    android:textColor="#000000"
                    android:textSize="10pt"
                    android:textStyle="bold" />

                <EditText
                    android:id="@+id/username"
                    android:layout_width="match_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:hint="Enter username"
                    android:singleLine="true"
                    android:textColor="#000000" >
                </EditText>
            </LinearLayout>

            <LinearLayout
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/PassInfo"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/UserInfo"
                android:orientation="horizontal" >

                <TextView
                    android:id="@+id/pwd"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:text="Password"
                    android:textColor="#000000"
                    android:textSize="10pt"
                    android:textStyle="bold" />

                <EditText
                    android:id="@+id/password"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:hint="Enterpassword"
                    android:singleLine="true"
                    android:textColor="#000000" />
            </LinearLayout>

            <LinearLayout
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/StoreNumInfo"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/WelcomeInfo"
                android:gravity="center_vertical"
                android:orientation="horizontal" >

                <TextView
                    android:id="@+id/num"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:text="Store Number"
                    android:textColor="#000000"
                    android:textSize="10pt"
                    android:textStyle="bold" />

                <EditText
                    android:id="@+id/store_num"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:hint="Enter the Store number"
                    android:imeOptions="actionDone"
                    android:password="true"
                    android:textColor="#000000" >
                </EditText>
            </LinearLayout>

            <LinearLayout
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/Options"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/PassInfo"
                android:orientation="horizontal" >

                <CheckBox
                    android:id="@+id/signed_in"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:text="Stay Signed-in"
                    android:textColor="#000000" />

                <Button
                    android:id="@+id/login"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"
                    android:text="Login"
                    android:textSize="28dp"
                    android:textStyle="bold" />
            </LinearLayout>
        </LinearLayout>
    </LinearLayout>

</ScrollView>

回答5:

In the parent LinearLayout , add this

android:orientation="vertical"
android:gravity="center"

.

回答6:

My Solution

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:gravity="center_vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <Button
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:layout_gravity="center"
       android:text="Sample Button"
       />


</LinearLayout>

来源：https://stackoverflow.com/questions/14150780/android-align-linearlayout-center-for-all-screen-sizes