CODEWITHSUNDEEP
androidandroid-layout
Dan
Dan

Reputation: 842

Implementing a dynamic Android layout

I am implementing an Android layout that acts as an instruction manual of sorts. So basically I have several pages that the user can flip through. Let's say I implemented it like this:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout  
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:id="@+id/page_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
        <!-- Put stuff for page 1 -->
    </LinearLayout>
    <LinearLayout
        android:id="@+id/page_2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page 2 -->
    </LinearLayout>
    <LinearLayout
        android:id="@+id/page_3"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page 3 -->
    </LinearLayout>

    <!-- ... -->

    <LinearLayout
        android:id="@+id/page_N"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page N -->
    </LinearLayout>
</FrameLayout>

Basically how I would simulate the "page flipping effect" (perhaps with animation) is to make the current page invisible and make the new page visible. However, this implementation has some problems:

  1. Since I'm basically loading all the pages at the same time, the Activity holding this layout will use up a lot of heap, especially if there's background images involved.
  2. The above problem is going to get worse as I expand the manual.
  3. I've considered splitting the pages into separate activities, but that seems a bit excessive and too troublesome.

I was thinking if there's a way to dynamically load a page from an XML file during run time. As in, would it be possible to inflate a particular layout whenever the user demands it? Or if anyone has a better implementation that I haven't though of, please tell me!

Upvotes: 0

Views: 442

Answers (3)

Samuel
Samuel

Reputation: 4387

Use a view flipper, for example

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

<ViewFlipper
    android:id="@+id/viewflipper"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <LinearLayout
        android:id="@+id/page_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
        <!-- Put stuff for page 1 -->
    </LinearLayout>
    <LinearLayout
        android:id="@+id/page_2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page 2 -->
    </LinearLayout>
    <LinearLayout
        android:id="@+id/page_3"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page 3 -->
    </LinearLayout>

    <!-- ... -->

    <LinearLayout
        android:id="@+id/page_N"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="INVISIBLE">
        <!-- Put stuff for page N -->
    </LinearLayout>
  </ViewFlipper>
</FrameLayout>

Now to flip between the different views, you would (in your java file) 

ViewFlipper flipper = (ViewFlipper) findViewById(R.id.viewflipper);
flipper.setInAnimation(AnimationUtils.loadAnimation(mContext, R.anim.exit_slide_right_left));
flipper.setOutAnimation(AnimationUtils.loadAnimation(mContext,R.anim.enter_slide_right_left));
flipper.setDisplayedChild(n);

which will slide as if you're flipping forward, the animation file looks like:

(enter_slide_right_left.xml)

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
         android:shareInterpolator="false">
        <translate android:fromXDelta="0%" android:toXDelta="-100%"
          android:fromYDelta="0%" android:toYDelta="0%"
         android:duration="700"/>
       </set>

and (exit_slide_right_left.xml)

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
         android:shareInterpolator="false">
      <translate
       android:fromXDelta="100%" android:toXDelta="0%"
       android:fromYDelta="0%" android:toYDelta="0%"
       android:duration="700" />
    </set>

Upvotes: 1

ElectronAnt
ElectronAnt

Reputation: 2195

Maybe have each page as a separate resource? That way, you can just put all the pages in an array, and retrieve individual pages by index.

Upvotes: 0

jeet
jeet

Reputation: 29199

You can simply Use ViewFlipper for that purpose, and add views to flipper dynamically as user demand for that page.

Upvotes: 2

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