How to expand a layout height with animation?

问题:

I couldn't find a good example for how to do this.

I have a RelativeLayout set with x height.

I want to add a button which expands the height to x+y height.

can someone refer me to a good example on how to do it programmatically?

回答1:

Please check below new edited answer as below. But here you need to know the exact new height.

public class LayoutAnimationActivity extends Activity 
{
    RelativeLayout ril1;
    Button btn;
    int initialHeight;
    int actualHeight;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);
        ril1=(RelativeLayout)findViewById(R.id.relativeLayout1);
        btn=new Button(this);
        btn.setWidth(100);
        btn.setHeight(200);
        btn.setText("Button");
        actualHeight=210;
        Ani a=new Ani();
        a.setDuration(2000);
        ril1.startAnimation(a);
    }

    class Ani extends Animation
    {
        public Ani() {
        }

        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            int newHeight;

            newHeight = (int)(initialHeight * interpolatedTime);

            ril1.removeAllViews();
            btn.setWidth(100);
            btn.setHeight(300);
            btn.setText("as");
            ril1.addView(btn);             
            ril1.getLayoutParams().height = newHeight;
            ril1.requestLayout();
        }

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

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

回答2:

You marked the solution that was closest. This is the exact solution. I had the same problem. Hopefully this answer will help others.

InstantiateResizeAnimation

ResizeAnimation resizeAnimation = new ResizeAnimation(
     view, 
     targetHeight, 
     startHeight
); 
resizeAnimation.setDuration(duration); 
view.startAnimation(resizeAnimation);

ResizeAnimation class should look like this

public class ResizeAnimation extends Animation {
    final int targetHeight;
    View view;
    int startHeight;

    public ResizeAnimation(View view, int targetHeight, int startHeight) {
        this.view = view;
        this.targetHeight = targetHeight;
        this.startHeight = startHeight;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        int newHeight = (int) (startHeight + targetHeight * interpolatedTime);
        //to support decent animation, change new heigt as Nico S. recommended in comments
        //int newHeight = (int) (startHeight+(targetHeight - startHeight) * interpolatedTime);
        view.getLayoutParams().height = newHeight;
        view.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;
    }
}

回答3:

You need a scale animation here is the official documentation

this is in code

private void animate() {
    ImageView imageView = (ImageView) findViewById(R.id.ImageView01);
    ScaleAnimation scale = new ScaleAnimation((float)1.0, (float)1.5, (float)1.0, (float)1.5);
    scale.setFillAfter(true);
    scale.setDuration(500);
    imageView.startAnimation(scale); 
}

回答4:

Two simple ways to do this without an Animation class:

1) Set android:animateLayoutChanges="true" in you xml layout file

2) Use a ViewProperty animator

layout.setPivot(0);
layout.animate().scaleY(scaleFactor).setDuration(500);

The pivot tells the view where to scale from, default is in the middle, which in my experience is almost never what you want. The duration is optional (default = 1000).

回答5:

final Button button1 = (Button) view.findViewById(R.id.button);
    final CollapseAnimator animator = new CollapseAnimator(topLayout);

    final ViewTreeObserver.OnGlobalLayoutListener listener = new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            int mHeight = button1.getMeasuredHeight();
            KLog.i("onGlobalLayout() mHeight:" + mHeight);
            animator.setValues(mHeight*2, mHeight);

        }
    };
    button1.getViewTreeObserver().addOnGlobalLayoutListener(listener);
    button1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            view.post(new Runnable() {
                @Override
                public void run() {
                    button1.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
                    animator.collapse();

                }
            });

        }
    });

and class

public class CollapseAnimator {
    private View view;
    private boolean collapse=true;
    private int duation=300;
    private int destHeight=300;
    private ValueAnimator animator;
    private int originHeight=0;
    private int from=0;
    private int to=0;


    public CollapseAnimator(View view ) {
        this.view = view;
    }

    public void setValues(int destHeight,int originHeight){
        this.destHeight = destHeight;
        this.originHeight=originHeight;
        from=originHeight;
        to=originHeight;
    }
    public void collapse(){


        from=to;
        if(collapse){

            to=destHeight;
            collapse=false;
        }else{
            to=originHeight;
            collapse=true;
        }
        KLog.i("from:" + from+",to:"+to);
        animator = ValueAnimator.ofInt(from, to);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                int val = (Integer) valueAnimator.getAnimatedValue();
                ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
                layoutParams.height = val;
                view.setLayoutParams(layoutParams);
            }
        });
        animator.setDuration(duation);
        animator.start();
    }
}