android - 当我在函数中使用它时，音频文件不播放

Question

我正在创建一个需要在按下按钮时播放音频的 Android 应用程序。但它不播放音乐，尽管其余代码正常运行。此外，上下文中存在一个错误，表明上下文无法解析为变量。

这是我的主要 Activity

public class BroadcastNewSms extends Activity {



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.androidexample_broadcast_newsms);
        Button b1;
        b1 = (Button) findViewById(R.id.button1);

        b1.setOnClickListener(new OnClickListener()

        {



        public void onClick(View v)

        {



            MediaPlayer mp;
            mp = MediaPlayer.create(context,R.raw.hospital_alarm);

            mp.start();

             String phoneNumber = "+9198zxxxxxxx";

            String message = "Ambulance sent!";



            SmsManager smsManager = SmsManager.getDefault();

            smsManager.sendTextMessage(phoneNumber, null, message, null, null);



        }
        });




    }
}

Answer 1

尝试使用 getApplicationContext() 方法代替 context

public class BroadcastNewSms extends Activity 
{
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.androidexample_broadcast_newsms);
        Button b1;
        b1 = (Button) findViewById(R.id.button1);
        b1.setOnClickListener(new OnClickListener()
        {
            public void onClick(View v)
            {
                MediaPlayer mp;
                mp = MediaPlayer.create(getApplicationContext(),R.raw.hospital_alarm);
                mp.start();
                String phoneNumber = "+9198989898";    
                String message = "Ambulance sent!";
                SmsManager smsManager = SmsManager.getDefault();
                smsManager.sendTextMessage(phoneNumber, null, message, null, null);
            }
        });
    }
}