Android TextView 动态设置显示居中或者靠左

/**

* @param tv

* 主要判断显示的TV 内容只为一行则居中显示，内容超过两行 则左对齐

*/

public static void setTextViewGravity(final TextView tv){

ViewTreeObserver vto = tv.getViewTreeObserver();

  vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

@Override

      public boolean onPreDraw() {

if(tv.getLineCount() ==1){

tv.setGravity(Gravity.CENTER);

        }else{

tv.setGravity(Gravity.LEFT|Gravity.CENTER);

        }

return true;

      }

});

}