android: how to visible portion of a view with animation?

Question

I have a invisible View behind of another View. I want to make this view visible with a translate animation and show only a part of the right side view. like this:

I don't want to use 9 patch image and resize that. this animation named "peek in"" in MS-PowerPoint.

Answer 1

You could try something like this

1) create a drawable resource rectangle_curved.xml as shown below

       <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="rectangle" android:padding="10dp">
        <solid android:color="#FFFFFF"/>
        <corners
            android:bottomRightRadius="350dp"
            android:bottomLeftRadius="0dp"
            android:topLeftRadius="0dp"
            android:topRightRadius="350dp"/>
        <stroke android:color="#50000000" android:width="2dp"/>
    </shape>

2) Set this as the background of the view which is expanding and collapsing. Here I have used a Framelayout which is expanding and collapsing

     <FrameLayout
        android:id="@+id/shape"
        android:layout_width="wrap_content"
        android:layout_height="50dp"
        android:background="@drawable/rectangle_curved"/>

3) Create a class to handle the expand/collapse animation as follows

        public class ResizeAnimation extends Animation {
            private int mWidth;
            private int mInitialWidth;
            private View mView;

            public ResizeAnimation(View view, int width) {
                mView = view;
                mWidth = width;
                mInitialWidth = view.getWidth();
            }

            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t) {
                int newWidth = mInitialWidth + (int) ((mWidth - mInitialWidth) * interpolatedTime);
                mView.getLayoutParams().width = newWidth;
                mView.requestLayout();
            }

            @Override
            public void initialize(int width, int height, int parentWidth, int parentHeight) {
                super.initialize(width, height, parentWidth, parentHeight);
            }

            @Override
            public boolean willChangeBounds() {
                return true;
            }
       }            

4) Finally, use it like this. Create a function to handle animation as follows

     private void animate(View shapeView, boolean isExpand) {  
        int width = isExpand ? 500 : 0; // 500 is the max width in pixels , you ca change it
        ResizeAnimation anim = new ResizeAnimation(shapeView, width);
        anim.setDuration(500);
        shape.startAnimation(anim);
     }

and call this function as follows

for expand animation : animate(myBackgroundView, true)

for collapse animation : animate(myBackgroundView, false)

EDIT: in this line of step 4: int width = isExpand ? 500 : 0; use 1 instead of 0. 0 not work properly. I don't know why.

private void animate(View view, boolean isExpand) {
    int width = isExpand ? 200 : 1; // 200 is the max width in pixels.
    //use a factor for same width on all screen size.
    DisplayMetrics metrics = getResources().getDisplayMetrics();
    int factor =(int)  metrics.density;
    ResizeAnimation anim = new ResizeAnimation(view, width * factor);
    anim.setDuration(500);
    view.startAnimation(anim);
}