该方法getSystemService（字符串）是未定义的类型听 [英] The method getSystemService(String) is undefined for the type Listen

问题描述

我想检查是否com.android.music运行，我发现了以下错误在这行 this.getSystemService（Context.ACTIVITY_SERVICE）;

I'm trying to check if com.android.music is running and I'm getting the following error on this line this.getSystemService(Context.ACTIVITY_SERVICE);

错误：

The method getSystemService(String) is undefined for the type Listen

code：

Code:

public boolean isMusicRunning() {

            ActivityManager activityManager = (ActivityManager) this.getSystemService(Context.ACTIVITY_SERVICE);
            List<RunningAppProcessInfo> procInfos = activityManager.getRunningAppProcesses();
            for (int i = 0; i < procInfos.size(); i++) {
                if (procInfos.get(i).processName.equals("com.android.music")) {
                    Toast.makeText(null, "music is running",
                            Toast.LENGTH_LONG).show();
                }
            }
        } 

如果你可以让我知道我在做什么错在这里，这将是伟大的！

If you could let me know what I'm doing wrong here that would be great!

感谢

推荐答案

getSystemService 是一个类的方法上下文，所以你需要在上下文中运行它。

getSystemService is a method of the class Context, so you'll need to run it on a context.

你可能是指其复制原来的code从一个活动派生类中运行。你需要通过一个上下文参数到你的方法，如果它不是一个活动里面。

The original code you copied it from was probably meant to be run from an Activity-derived class. You need to pass a Context argument into your method if it's not inside an Activity.

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