上下文未被识别：方法不适用于参数 [英] Context not recognisied:Method not applicable for arguments

问题描述

我正试图让一个定时器在我的Android应用程序中每1.5秒播放MP3文件（哔声）。我有以下代码并收到错误MediaPlayer类中的方法create（context，int）不适用于我的运行函数中的参数（Beep.RemindTask，int）：

I'm trying to make a timer to play an MP3 file every 1.5 seconds(a beep) in my android application. I have the following code and receive the error "The method create (context,int) in the type MediaPlayer is not applicable for the arguments (Beep.RemindTask,int)" in my run function below:

package com.example.timer;

import java.util.Timer;
import java.util.TimerTask;
import android.media.AudioManager;
import android.media.MediaPlayer;

public class Beep {

 Timer timer;

    public Beep() {

        timer = new Timer();
        timer.schedule(new RemindTask(),
                   0,        //initial delay
                   1*1500);  //subsequent rate
    }

    class RemindTask extends TimerTask {



        public void run() {

            MediaPlayer mPlayer = MediaPlayer.create(this, R.raw.beep); 
            mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mPlayer.start();


        }
    }

    public void main(String args[]) {

        new Beep();

    }
}

我不明白为什么不适用，参数是否相同？我知道它可能与上下文有关，我不太清楚，但是从这里： Android上的上下文是什么？我知道在创建新对象或访问共享共享资源时使用它们。我试过 getApplicationContext（）， getContext（）和 getBaseContext（）但仍然收到错误。我相信哔哔声对象所需要的一切都在这个上下文中。任何建议或想法？

I don't understand why it isn't applicable, the parameters being the same? I know its probably something to do with the context, which I am not entirely sure of, but from here: What is 'Context' on Android? I know they are used when creating new objects or accessing shared common resources. I have tried getApplicationContext(),getContext() and getBaseContext() but still receive errors. I believe that everything needed by the beep object to operate is located in this context. Any suggestions or ideas?

推荐答案

你的课是一个非活动类，所以你不能直接得到一个上下文。当您从活动中实例化Beep的实例时，请在构建器中传入活动的上下文。

Your class is a non-activity class so you can't directly get at a context. When you instantiate an instance of Beep from your activity, pass in the activity's context in the constuctor.

将一个变量添加到您的Beep类以保存上下文：

Add a variable to your Beep class to hold a context:

private Context context;

在构造函数中存储：

public Beep(Context context) {
this.context=context;
//the rest of your constructor code...
}

然后你可以这样做：

MediaPlayer mPlayer = MediaPlayer.create(context, R.raw.beep);

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