安卓中如何監聽某些app打開

需求：編寫一個程式能夠監聽到一些app曾經打開并且在程式裡面顯示是否打開過，比如com.liulishuo.engzo（英語流利說app）的打開；

思路：

首先要有一個Service在背景能夠知道任務棧頂端程式是否是com.liulishuo.engzo這樣的包名；

如果指定的一個app中包含任務棧頂端的包名，那麼就把這個包名和true值存儲在SharedPreferences中；

這些app的包名用bindService方式動态傳遞Service中；

涉及到的知識點：正在running的任務棧知識、Service的bind知識；

WatchDogService.java

public class WatchDogService extends Service {

    private List<String> packageList = new ArrayList<>();
    private static final String TAG = "WatchDogService";
    private static boolean flag = true;// 線程退出的标記
    private ActivityManager am;
    private SharedPreferences isOpenSP;
    private SharedPreferences.Editor editor;

    @Override
    public void onCreate() {
        super.onCreate();
        // 服務一旦啟動要在背景監視任務棧最頂端應用
        am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        isOpenSP = getSharedPreferences("isOpen", Context.MODE_PRIVATE);
        editor = isOpenSP.edit();

        new Thread() {
            @Override
            public void run() {
                super.run();
                while (flag) {
                    synchronized (WatchDogService.class) {
                        List<ActivityManager.RunningTaskInfo> runningTasks = am.getRunningTasks();
                        ActivityManager.RunningTaskInfo runningTaskInfo = runningTasks.get();
                        ComponentName topActivity = runningTaskInfo.topActivity;
                        String packageName = topActivity.getPackageName();

                        if (packageList.contains(packageName)) {
                            // 判斷packageName是否已打開
                            boolean isOpen = isOpenSP.getBoolean(packageName, false);
                            if (!isOpen) {
                                editor.putBoolean(packageName, true);
                                editor.apply();
                                Log.i(TAG, packageName + "正在存儲");
                            }
                        }
                        SystemClock.sleep();
                    }
                    Log.i(TAG, "服務在循環");
                }
            }
        }.start();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        flag = false;
    }

    public class MyBinder extends Binder implements IMyBinder {

        @Override
        public void setPackageNames(List<String> packageNames) {
            packageList.clear();
            packageList.addAll(packageNames);
        }
    }

    MyBinder myBinder = new MyBinder();
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return myBinder;
    }
}
           

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    private TextView textView1;
    private SharedPreferences isOpennSP;
    private IMyBinder iMyBinder;
    private List<String> packageList = new ArrayList<>();
    private MyServiceConnection connection;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView1 = (TextView) findViewById(R.id.tv1);

        isOpennSP = getSharedPreferences("isOpen", Context.MODE_PRIVATE);

        initData();

        connection = new MyServiceConnection();
        bindService(new Intent(this, WatchDogService.class), connection, Context.BIND_AUTO_CREATE);
    }

    private void renderView() {
        textView1.setText(isOpennSP.getBoolean(packageList.get(), false) ? packageList.get() + "已打開" : packageList.get() + "未打開");
    }

    @Override
    protected void onResume() {
        super.onResume();
        renderView();
    }

    private void initData() {
        packageList.clear();
        packageList.add("com.liulishuo.engzo");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(connection);
    }

    public class MyServiceConnection implements ServiceConnection {

        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            iMyBinder = (IMyBinder) iBinder;
            iMyBinder.setPackageNames(packageList);
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {
        }
    }
}
           

IMyBinder.java

public interface IMyBinder {
    void setPackageNames(List<String> packageNames);
}
           

MyApplication.java

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        startService(new Intent(this, WatchDogService.class));
    }
}
           

MainActivity中的bindService方法中攜帶了connection對象，一旦綁定成功會回調MyServiceConnection類中onServiceConnected方法，我們代碼中用到的是第二個參數iBinder對象，這個對象是WatchDogService傳回給我們的；

public class MyServiceConnection implements ServiceConnection {

        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            iMyBinder = (IMyBinder) iBinder;
            iMyBinder.setPackageNames(packageList);
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {
        }
    }
           

再看WatchDogService中的onBind方法中傳回了MyBinder對象

public class MyBinder extends Binder implements IMyBinder {

        @Override
        public void setPackageNames(List<String> packageNames) {
            packageList.clear();
            packageList.addAll(packageNames);
        }
    }

MyBinder myBinder = new MyBinder();
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return myBinder;
    }
           

這個myBinder對象就是從onBind方法中傳回的，給了Activity中的MyServiceConnection 中的onServiceConnected方法的第二個參數，我們就是通過這個參數在Activity中去給Service中的packageNames集合指派的。