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Wednesday, February 4, 2015

Android beginner tutorial Part 7 LinearLayout container

Today well take a look at the LinearLayout container.

The LinearLayout container stacks its children either horizontally or vertically, one after another. To set the orientation, you need to use the android:orientation attribute of the tag.

Lets edit the code from our previous tutorial to create an Activity layout which consists of a LinearLayout with horizontal orientation and 3 children. Set the width and height of the layout tag to match_parent, and set each buttons width and height to wrap_content:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    tools:context=".MainActivity" >

    <Button 
        android:text="Test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 2" />
    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 3" />
    
</LinearLayout>

The results:

Lets see what happens if we set orientation to vertical:

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

    <Button 
        android:text="Test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 2" />
    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 3" />
    
</LinearLayout>

Results:

You can also use a very useful attribute called layout_weight for children of a LinearLayout.

This attribute basically sets the priority level for this child. The values for this attribute are numbers. The whole weight system is comparable to a cooking recipe, for example: 3 parts of milk and 2 parts of ice cream. This means that in the final product there will be 60% milk and 40% ice cream.

If we use a horizontal linear layout, we can use the layout_weight attribute to make interface elements flex depending on the device screen size. Heres an example, which gives the first button 1/6 of the total width, the second button 1/3 (2/6) of the width and the third button 1/2 (3/6) of the whole row width.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    tools:context=".MainActivity" >

    <Button 
        android:text="Test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 2"
        android:layout_weight="2"/>
    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 3"
        android:layout_weight="3"/>
    
</LinearLayout>

The results:

You can also use LinearLayouts inside other LinearLayouts. Heres an example:

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

    <Button 
        android:text="Test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 2"
        android:layout_weight="2"/>
    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 3"
        android:layout_weight="3"/>
    
</LinearLayout>

<LinearLayout 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <Button 
        android:text="Test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test 2"
        android:layout_weight="2"/>
</LinearLayout>
    
</LinearLayout>

Results:

Thats all for today!

Thanks for reading!

Hard Reset 7 inch APPTAB Android Tablet RK3066 Rockchip

Hard Reset APPTAB

7 inch Android Tablet via Android System Recovery.

RK3066 Rockchip .

Step by Step Tutorial .

Forgotten Pattern Lock , Gmail Account , Reset User Lock on Android Tablet

What is Hard Reset ?

hard reset is also called Factory reset. its a situation when you restore your Android device to state when it left the factory or first time the Smartphones or Tablets turns on . Hard Reset erase all user setting,contents (i.e games,contacts,messages,apps preference setting ,bookmarks,third party apps as well .) So if youre enough lucky then you can make backup of all your data before hard reset .In most cases user data lost. Different Android Devices have different method for Hard Reset.

Forgotten Pattern Lock on APPTAB 7 Inch Android Tablet.

APPTAB 7 inch Android Tablet is available without Power buttons. Power buttons play major role when it comes to Android System Recovery. This is a bit tricky. I have spend a lot of time to find out how to Hard Reset this unknown tablet . I succeed so like to share it .

1. Turn off APPTAB completely by holding power button.

2. Now turn on android tablet .

3. When logo appear , press home button .

4. Few second later recovery menu will be appear .

5. Select wipe data / factory reset by pressing home button. (you can wipe cache partition as well ).

6. To select the option press power button.

7. Confirm Yes by pressing power button.

8. Wiping Data.

9. Reboot .