显示来自Application类的Toast消息 [英] Displaying a Toast message from the Application class

问题描述

我的应用程序中有几个类.一些是活动，服务和纯Java类.我知道我可以在Activity中显示Toast消息，但我想从纯Java类显示Toast.

I have several classes in my application. Some are Activities, Services and Pure java classes. I know i can display a Toast message from within an Activity but i'd like to display a Toast from a pure java class.

在java类中，我将上下文传递给构造函数，但这似乎没有显示吐司面包.

In the java class i pass a context in to the constructor but this doesn't seem to show the toast.

我已经在Application类中创建了一个方法，该方法将String作为参数，希望我可以使用Application上下文生成Toast，在这里也不高兴.

I have created a method in the Application class that takes a String as an argument, hoping i could generate a Toast using the Application context, no joy here either.

如何从不是服务或活动等的类中生成Toast.

How can i generate a Toast from a class that isn't a service or Activity etc.

public class LoginValidate{

public LoginValidate(Context context) {

        this.context = context;

        nfcscannerapplication = (NfcScannerApplication) context
                .getApplicationContext();


    }

public void someMethod(){

nfcscannerapplication.showToastMessage(result);

}

}

.

///然后在我的Application类中

///then in my Application class

public void showToastMessage(String message){

            Toast.makeText(this.getApplictionContext(), "Encountered a problem with sending tag: " + message, Toast.LENGTH_LONG).show();

    }

推荐答案

首先创建像这样的Application类..

First create Application class like this..

public class ApplicationContext extends Application {

/** Instance of the current application. */
private static ApplicationContext instance;

/**
 * Constructor.
 */
public ApplicationContext() {
    instance = this;
}

/**
 * Gets the application context.
 * 
 * @return the application context
 */
public static Context getContext() {
    if (instance == null) {
        instance = new ApplicationContext();
    }
    return instance;
}

/**
     * display toast message
     * 
     * @param data
     */
    public static void showToast(String data) {
        Toast.makeText(getContext(), data,
                Toast.LENGTH_SHORT).show();
    }

}

从任何类(例如ApplicationContext.showToast("your string");

当心上下文对象泄漏..

be careful about context object leaking..

这篇关于显示来自Application类的Toast消息的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！