Checking if the Android application was in foreground.

BaseActivity.java

package jp.tangerinebox.check_is_foreground;

import android.app.Activity;

public abstract class BaseActivity extends Activity{

    @Override
    protected void onStart(){
        super.onStart();

        HogeApplication.getInstance().onActivityStart();
    }

    @Override
    protected void onStop(){
        super.onStop();

        HogeApplication.getInstance().onActivityStop();
    }
}

HogeApplication.java

package jp.tangerinebox.check_is_foreground;

import android.app.Application;

public class HogeApplication extends Application{

    //  ====    Singleton用  ====

    private static HogeApplication sInstance = null;

    public static HogeApplication getInstance(){
        return sInstance;
    }

    @Override
    public void onCreate(){
        super.onCreate();

        sInstance = this;
    }


    //  ====    フォアグラウンドチェック    ====

    private int mStartCount = 0;
    private int mStopCount = 0;

    void onActivityStart(){
        ++ mStartCount;
    }

    void onActivityStop(){
        ++ mStopCount;
    }

    public boolean isForeground(){
        return mStartCount > mStopCount;
    }
}