In this project I implemented a menu using view pager. To implement this menu , i use view pager. First and third page are the menu page and second page is our content frame.
When we slide our page , say left to right. when first menu appear. What i have done is.
- Set the page translation of first page (one with negative position offset) to 0.
- Resize The content page.
- Shift the content page to align to parent right.
PageTransformer is the interface which will control all our transformation.
public class HorizontalReside implements ViewPager.PageTransformer {
@Override
public void transformPage(View page, float position) {
//Hiding those pages which are way off-screen to the left or to the right.
if (position < -1) {
page.setAlpha(0);
} else if (position > 1) {
page.setAlpha(0);
} else {
page.setAlpha(1);
}
if (page.getId() == R.id.menuFirst){
//putting fragment to the start of the screen
page.setTranslationX(-position*page.getWidth());
}
else if (page.getId() == R.id.contentPage){
//when we swipe to left this code applied
if (position <= 0){
//for each transformation CODE is mentioned below
}
//when we swipe to right this code applied
else if (position > 0){
//for each transformation CODE is mentioned below
}
}
else if (page.getId() == R.id.menuSecond){
//putting fragment to the start of the screen
page.setTranslationX(-position*page.getWidth());
}
}
}In above code R.id.menuFirst & R.id.menuSecond are left and right menu fragments respectively, so we set them to the start of the screen.
R.id.contentPage is the fragment which is always visible to user when the user starts the app. For this we have to code the animation When the user swipe to left and When the user swipe to right. Also to show R.id.contentPage on top set this fragment parent layout elevation by doing this the fragment comes over the first frgament.
android:elevation="10dp"To set R.id.contentPage is always shown to user whenever user starts the app you can use this
viewPager.setCurrentItem(1);You can download the latest sample APK from Google Play store:
if (position <= 0){
//first we do scaling to 50%
float scale = Math.max(0.6f,1-Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaWidth = page.getWidth() - scale*page.getWidth();
//place the fragment to the start of the screen and move the fragment to left
page.setTranslationX(-position*page.getWidth() - deltaWidth/2);
}
//when we swipe to right this code applied
else if (position > 0){
//first we do scaling to 50%
float scale = Math.max(0.6f,1-Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaWidth = page.getWidth() - scale*page.getWidth();
//place the fragment to the start of the screen and move the fragment to right
page.setTranslationX(-position*page.getWidth() + deltaWidth/2);
}
//when we swipe to left this code applied
if (position <= 0){
//first we do scaling to 50%
float scale = Math.max(0.6f,1-Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaHeight = page.getHeight() - scale*page.getHeight();
//move the fragment to top
page.setTranslationY(+deltaHeight/2);
}
//when we swipe to right this code applied
else if (position > 0){
//first we do scaling to 50%
float scale = Math.max(0.6f,1-Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaHeight = page.getHeight() - scale*page.getHeight();
//move the fragment to bottom
page.setTranslationY(-deltaHeight/2);
}
//when we swipe to left this code applied
if (position <= 0) {
//first we do scaling to 50%
float scale = Math.max(0.5f, 1 - Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaHeight = page.getHeight() - scale * page.getHeight();
float deltaWidth = page.getWidth() - scale * page.getWidth();
//move the fragment to top
page.setTranslationY(+deltaHeight / 2);
//place the fragment to the start of the screen and move the fragment to left
page.setTranslationX(-position * page.getWidth() - deltaWidth / 2);
}
//when we swipe to right this code applied
else if (position > 0) {
//first we do scaling to 50%
float scale = Math.max(0.5f, 1 - Math.abs(position));
page.setScaleX(scale);
page.setScaleY(scale);
float deltaHeight = page.getHeight() - scale * page.getHeight();
float deltaWidth = page.getWidth() - scale * page.getWidth();
//move the fragment to bottom
page.setTranslationY(-deltaHeight / 2);
//place the fragment to the start of the screen and move the fragment to right
page.setTranslationX(-position * page.getWidth() + deltaWidth / 2);
}