封装 Toast

一、 ToastView.java

 1 import android.content.Context;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 import android.widget.Toast;

 public class ToastView extends LinearLayout{
     private static ToastView mToastView;

     private TextView toastText;
     private ImageView toastIcon;
     private Context mContext;

     private View layout;
     private Toast mToast;

     private ToastView(Context context) {
         super(context,null);
         mContext = context;
         LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         layout = inflater.inflate(R.layout.toast, null);  

         toastIcon = (ImageView) layout.findViewById(R.id.toastIcon);
         toastText = (TextView) layout.findViewById(R.id.toastText);
     }

     public static ToastView getInstance(Context context) {
         if (mToastView != null) {
             return mToastView;
         } else {
             if (context != null) {
                 mToastView = new ToastView(context);
                 return mToastView;
             } else {
                 return null;
             }
         }
     }

     public void setIconVisiblity(int visiblity){
         toastIcon.setVisibility(visiblity);
     }

     public void showToast(String str,int gravity,int xoffset,int yoffest) {
         toastText.setText(str);

         if(mToast!=null){
             mToast.setGravity(gravity,xoffset,yoffest);
             mToast.show();
         }else{
             mToast= new Toast(mContext);
             mToast.setView(layout);
             mToast.setGravity(gravity,xoffset,yoffest);
             mToast.setDuration(Toast.LENGTH_SHORT);
             mToast.show();
         }
     }

     public void showToast(String str,int gravity,int xoffset,int yoffest,int duration) {
         toastText.setText(str);
         duration = duration<=0 ? Toast.LENGTH_SHORT : duration;

         if(mToast!=null){
             mToast.setGravity(gravity,xoffset,yoffest);
             mToast.setDuration(duration);
             mToast.show();
         }else{
             mToast= new Toast(mContext);
             mToast.setView(layout);
             mToast.setGravity(gravity,xoffset,yoffest);
             mToast.setDuration(duration);
             mToast.show();
         }
     }

 }

二、toast.xml

 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:gravity="center_vertical">

     <TextView
         android:id="@+id/toastText"
         android:layout_width="wrap_content"
         android:layout_height="@dimen/toastHeight"
         android:textColor="@color/title_text_color"
         android:background="@drawable/toast_bg"
         android:gravity="center"
         android:paddingLeft="@dimen/toastTextPaddingLeft"
         android:paddingRight="@dimen/toastTextPaddingRight"
         android:textSize="@dimen/toastTextSize"/>

     <ImageView
         android:id="@+id/toastIcon"
         android:layout_width="@dimen/toastIconWidth"
         android:layout_height="@dimen/toastIconWidth"
         android:layout_marginLeft="@dimen/toastIconWidth"
         android:scaleType="fitXY"
         android:layout_centerVertical="true"
         android:src="@drawable/toast_icon" />
 </RelativeLayout>

三、Acitivity中调用

    //自定义的
    private void showToast(String str, int offset) {
        ToastView toast = ToastView.getInstance(RecommendActivity.this);
        if(offset < 0){
            toast.showToast(str, Gravity.TOP | Gravity.CENTER_HORIZONTAL,0,　　　　//默认时长的Toast
                    (int)getResources().getDimension(R.dimen.defaultToastMarginTop));
        }else{
            toast.showToast(str, Gravity.TOP | Gravity.CENTER_HORIZONTAL,0,　　　　//自定义时长的Toast
                    (int)getResources().getDimension(R.dimen.defaultToastMarginTop), offset);
        }
    }

封装的这个Toast没什么技术含量。

但是，之所以把Toast定义为单例模式，是为了防止疯狂点击按钮，出现连续不断的Toast

因为系统的Toast是维护一个队列，每次cancle只对当前的Toast 有用。所以之后的Toast还是会不停出现

这个Toast改为单例模式之后。如果当前Toast不为空，只对其进行setText。然后show（不调用show不会出现）

如果当前为空，才会新建一个ToastView。