expand View in Animation - Android Animation

Android examples for Animation:Expand Animation

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  4. Expand Animation

Description

expand View in Animation

Demo Code


//package com.java2s;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.widget.LinearLayout;

public class Main {
    public static void expand(final View v) {
        v.measure(LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        final int targetHeight = v.getMeasuredHeight();

        // Older versions of android (pre API 21) cancel animations for views with a height of 0.
        v.getLayoutParams().height = 1;//  w w  w  .  j a v a 2 s .c om
        v.setVisibility(View.VISIBLE);
        Animation a = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime,
                    Transformation t) {
                v.getLayoutParams().height = interpolatedTime == 1 ? LinearLayout.LayoutParams.WRAP_CONTENT
                        : (int) (targetHeight * interpolatedTime);
                v.requestLayout();
            }

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

        // 1dp/ms
        a.setDuration((int) (targetHeight / v.getContext().getResources()
                .getDisplayMetrics().density));
        v.startAnimation(a);
    }
}

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