安卓中如何监听某些app打开

需求：编写一个程序能够监听到一些app曾经打开并且在程序里面显示是否打开过，比如com.liulishuo.engzo（英语流利说app）的打开；

思路：

首先要有一个Service在后台能够知道任务栈顶端程序是否是com.liulishuo.engzo这样的包名；

如果指定的一个app中包含任务栈顶端的包名，那么就把这个包名和true值存储在SharedPreferences中；

这些app的包名用bindService方式动态传递Service中；

涉及到的知识点：正在running的任务栈知识、Service的bind知识；

WatchDogService.java

public class WatchDogService extends Service {

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

@Override
public void onCreate() {
super.onCreate();
// 服务一旦启动要在后台监视任务栈最顶端应用
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(1);
ActivityManager.RunningTaskInfo runningTaskInfo = runningTasks.get(0);
ComponentName topActivity = runningTaskInfo.topActivity;
String packageName = topActivity.getPackageName();

if (packageList.contains(packageName)) {
// 判断packageName是否已打开
boolean isOpen = isOpenSP.getBoolean(packageName, false);
if (!isOpen) {
editor.putBoolean(packageName, true);
editor.apply();
Log.i(TAG, packageName + "正在存储");
}
}
SystemClock.sleep(500);
}
Log.i(TAG, "服务在循环");
}
}
}.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(0), false) ? packageList.get(0) + "已打开" : packageList.get(0) + "未打开");
}

@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方法中携带了connection对象，一旦绑定成功会回调MyServiceConnection类中onServiceConnected方法，我们代码中用到的是第二个参数iBinder对象，这个对象是WatchDogService返回给我们的；

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方法中返回了MyBinder对象

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;
}

这个myBinder对象就是从onBind方法中返回的，给了Activity中的MyServiceConnection 中的onServiceConnected方法的第二个参数，我们就是通过这个参数在Activity中去给Service中的packageNames集合赋值的。