工具类ToastUtil 避免在子线程中使用抛异常 "Can't create handler inside thread that has not called Looper.prepare()"

 package com.example.kbr.utils;

 import android.view.Gravity;
 import android.widget.Toast;

 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;

 /**
  * Created by keranbin on 2017/12/19.
  */

 public class ToastUtil {
     private static Toast toast;

     /**
      * 短时间显示Toast【居上】
      *
      * @param msg 显示的内容-字符串
      */
     public static void showShortToastTop(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             Observable.create(emit -> {

             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_SHORT);
                             toast.setGravity(Gravity.TOP, 0, 0);
                         } else {
                             toast.setText(msg);
                         }
                         toast.show();
                     });
         }
     }

     /**
      * 短时间显示Toast【居中】
      *
      * @param msg 显示的内容-字符串
      */
     public static void showShortToastCenter(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             io.reactivex.Observable.create(emit -> {
                 emit.onNext(msg);
                 emit.onComplete();
             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_SHORT);
                         } else {
                             toast.setText(msg);
                         }
 //                        toast.setGravity(Gravity.CENTER,0,0); 默认居中显示
                         toast.show();
                     });

         }
     }

     /**
      * 短时间显示Toast【居下】
      *
      * @param msg
      */
     public static void showShortToast(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             Observable.create(emit -> {
                 emit.onNext(msg);
                 emit.onComplete();
             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_SHORT);
                         } else {
                             toast.setText(msg);
                         }
                         toast.setGravity(Gravity.BOTTOM, 0, 0);
                         toast.show();
                     });

         }
     }

     /**
      * 长时间显示Toast【居上】
      *
      * @param msg 显示的内容-字符串
      */
     public static void showLongToastTop(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             Observable.create(emit -> {
                 emit.onNext(msg);
                 emit.onComplete();
             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_LONG);
                         } else {
                             toast.setText(msg);
                         }
                         toast.setGravity(Gravity.TOP, 0, 0);
                         toast.show();
                     });
         }

     }

     /**
      * 长时间显示Toast【居中】
      *
      * @param msg 显示的内容-字符串
      */
     public static void showLongToastCenter(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             Observable.create(emit -> {
                 emit.onNext(msg);
                 emit.onComplete();
             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_LONG);
                         } else {
                             toast.setText(msg);
                         }
 //                        toast.setGravity(Gravity.CENTER, 0, 0);  //默认居中显示
                         toast.show();
                     });
         }

     }

     /**
      * 长时间显示Toast【居下】
      *
      * @param msg 显示的内容-字符串
      */
     public static void showLongToast(String msg) {
         if (EmptyUtil.isNotEmpty(msg) && EmptyUtil.isNotEmpty(App.getContext())) {
             Observable.create(emit -> {
                 emit.onNext(msg);
                 emit.onComplete();
             }).observeOn(AndroidSchedulers.mainThread())
                     .subscribe(re -> {
                         if (toast == null) {
                             toast = Toast.makeText(App.getContext(), msg, Toast.LENGTH_LONG);
                         } else {
                             toast.setText(msg);
                         }
                         toast.setGravity(Gravity.BOTTOM, 0, 0);  //默认居中显示
                         toast.show();
                     });
         }
     }
 }