Android - Animation in Code - Một số Animation - hiệu ứng trong Android Studio

// mở rộng một view

public static void expand(final View v) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.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;
v.setVisibility(View.VISIBLE);
Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
v.getLayoutParams().height = interpolatedTime == 1
? ViewGroup.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);
}

// thu nhỏ lại

public static void collapse(final View v) {
final int initialHeight = v.getMeasuredHeight();

Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (interpolatedTime == 1) {
v.setVisibility(View.GONE);
} else {
v.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime);
v.requestLayout();
}
}

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

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

// kéo dãn view từ 0

public static void scaleView(View v) {
Animation anim = new ScaleAnimation(
0f,1f , // Start and end values for the X axis scaling
0f, 1f, // Start and end values for the Y axis scaling
Animation.RELATIVE_TO_SELF, 0.5f, // Pivot point of X scaling
Animation.RELATIVE_TO_SELF, 0.5f); // Pivot point of Y scaling
anim.setFillAfter(true); // Needed to keep the result of the animation
anim.setDuration(250);
v.startAnimation(anim);
}