Toast类避免显示时间叠加的方法

import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.widget.Toast;
 
/**
 * Toast工具类
 * Created by user on 2016/12/22.
 */
 
public class ToastUtil {
 
  private static Toast toast = null;
  private static ToastUtil toastUtil = null;
 
  public ToastUtil(){}
 
  public synchronized static ToastUtil getInstance(){
    if(null == toastUtil){
      toastUtil = new ToastUtil();
    }
 
    return toastUtil;
  }
 
  public void showToast(Context context, String string){
 
    if(toast != null){
      toast.cancel();
    }
      toast = Toast.makeText(context, string,Toast.LENGTH_SHORT);
      toast.show();
  }
 
  public void showToast(Fragment fragment, String string){
    showToast(fragment.getActivity(),string);
  }
 
  public void showToast(Activity activity, String string){
    if(toast != null){
      toast.cancel();
    }
    toast = Toast.makeText(activity, string,Toast.LENGTH_SHORT);
    toast.show();
  }
 
  public void showToastTest(Context context){
    if(toast != null){
      toast.cancel();
    }
    toast = Toast.makeText(context, "click",Toast.LENGTH_SHORT);
    toast.show();
  }
 
  public void showToastTest(Fragment fragment){
    showToastTest(fragment.getActivity());
  }
 
  public void showToastTest(Activity activity){
    if(toast != null){
      toast.cancel();
    }
    toast = Toast.makeText(activity, "click",Toast.LENGTH_SHORT);
    toast.show();
  }
}
 
    if(null == toastUtil){
      toastUtil = new ToastUtil();
    }
 
    return toastUtil;
  }
public void showToastInThread(Context context,String msg){
    Looper.prepare();
    if(toast != null){
      toast.cancel();
    }
    toast = Toast.makeText(context,msg,Toast.LENGTH_SHORT);
    toast.show();
    Looper.loop();
  }
  public void showToast(Context context, String string){
 
    if(toast != null){
      toast.cancel();
    }
      toast = Toast.makeText(context, string,Toast.LENGTH_SHORT);
      toast.show();
  }
 
}

ToastUtil.getInstance().showToast(mContext,"test");

ToastUtil.getInstance().showToastInThread(mContext,"str");