动画实现两种方式：
ObjectAnimator animator1 = ObjectAnimator.ofFloat(tvContent1, View.TRANSLATION_Y, hFrom, hTo);
ObjectAnimator animator1 = ObjectAnimator.ofInt(wrapper, "height", hFrom, hTo);
但是效果完全不同：
如下图:
public class SecondActivity extends AppCompatActivity {private TextView tvTitle1, tvTitle2;private TextView tvContent1, tvContent2;private ViewWrapper wrapper;private int height1, height2;private boolean isAnimating1, isAnimating2;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_second);tvTitle1 = (TextView) findViewById(R.id.tv_title);tvContent1 = (TextView) findViewById(R.id.tv_content);tvTitle2 = (TextView) findViewById(R.id.tv_title2);tvContent2 = (TextView) findViewById(R.id.tv_content2);wrapper = new ViewWrapper(tvContent2);initHeight();tvTitle1.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {startAnimator1();}});tvTitle2.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {startAnimator2();}});}private void initHeight() {tvContent1.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {@Overridepublic void onGlobalLayout() {height1 = tvContent1.getHeight();tvContent1.getViewTreeObserver().removeOnGlobalLayoutListener(this);}});tvContent2.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {@Overridepublic void onGlobalLayout() {height2 = tvContent2.getHeight();tvContent2.getViewTreeObserver().removeOnGlobalLayoutListener(this);}});}private void startAnimator1() {if (isAnimating1) return;final boolean isExpand = (View.VISIBLE == tvContent1.getVisibility());int hFrom = 0, hTo = 0;if (!isExpand) {//已显示，需要隐藏hFrom = -height1;} else {//已隐藏 需要显示hTo = -height1;}ObjectAnimator animator1 = ObjectAnimator.ofFloat(tvContent1, View.TRANSLATION_Y, hFrom, hTo);animator1.setDuration(1000);tvContent1.setVisibility(View.VISIBLE);animator1.addListener(new AnimatorListenerAdapter() {@Overridepublic void onAnimationStart(Animator animation) {super.onAnimationStart(animation);isAnimating1 = true;}@Overridepublic void onAnimationEnd(Animator animation) {super.onAnimationEnd(animation);isAnimating1 = false;tvContent1.setVisibility(isExpand ? View.GONE : View.VISIBLE);}});animator1.start();}private void startAnimator2() {if (isAnimating2) return;final boolean isExpand = (View.VISIBLE == tvContent2.getVisibility());int hFrom = 0, hTo = 0;if (isExpand) {//已显示，需要隐藏hFrom = height2;} else {//已隐藏 需要显示hTo = height2;}ObjectAnimator animator2 = ObjectAnimator.ofInt(wrapper, "height", hFrom, hTo);animator2.setDuration(1000);tvContent2.setVisibility(View.VISIBLE);animator2.addListener(new AnimatorListenerAdapter() {@Overridepublic void onAnimationStart(Animator animation) {super.onAnimationStart(animation);isAnimating2 = true;}@Overridepublic void onAnimationEnd(Animator animation) {super.onAnimationEnd(animation);isAnimating2 = false;tvContent2.setVisibility(isExpand ? View.GONE : View.VISIBLE);}});animator2.start();}
}