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。