问题
I have to develop an app locker for Android where the user can block apps and other users can not access these apps without an access key.
I have installed an app but I don't know how to lock this app.
Please suggest me something.
回答1:
This is not how stack overflow works. You can not ask a complete solution without even trying anything.
For the most basic version of your app, you need to perform three functions.
Get a list of all the installed apps on device and show them in a ListView with check box. If the user checks any app, add the app to a different list say BlockedAppsList(which will be the list of apps which user wants to block). You can get all the apps installed using the following code:
final PackageManager pm = getPackageManager(); //get a list of installed apps. List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA); for (ApplicationInfo packageInfo : packages) { Log.d(TAG, "Installed package :" + packageInfo.packageName); Log.d(TAG, "Source dir : " + packageInfo.sourceDir); Log.d(TAG, "Launch Activity :" + pm.getLaunchIntentForPackage(packageInfo.packageName)); }Check the which is the current opened app. You can check by using this code:
ActivityManager am = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE); List l = am.getRecentTasks(1, ActivityManager.RECENT_WITH_EXCLUDED); Iterator i = l.iterator(); PackageManager pm = this.getPackageManager(); while (i.hasNext()) { ActivityManager.RunningAppProcessInfo info = (ActivityManager.RunningAppProcessInfo)(i.next()); try { CharSequence c = pm.getApplicationLabel(pm.getApplicationInfo( info.processName, PackageManager.GET_META_DATA)); Log.w("LABEL", c.toString()); } catch (Exception e) { // Name Not FOund Exception } }Now check if the current app is present in the BlockedAppsList, if it is there, you can show any screen with a block message.
good luck!
回答2:
Assuming that you store the package names of locked apps in a table called:
locks
and you want to call an activity named
PasswordActivity
when ever the users launch a locked app, you can implement a polling mechanism like below:
public class CheckAppLaunchThread extends Thread {
private Context context;
private Handler handler;
private ActivityManager actMan;
private int timer = 100;
public static final String TAG = "App Thread";
public static String lastUnlocked;
// private String lastUnlocked;
public CheckAppLaunchThread(Handler mainHandler, Context context) {
this.context = context;
this.handler = mainHandler;
actMan = (ActivityManager) context
.getSystemService(Context.ACTIVITY_SERVICE);
this.setPriority(MAX_PRIORITY);
}
@Override
public void run() {
context.startService(new Intent(context, AppLockService.class));
Looper.prepare();
String prevTasks;
String recentTasks = "";
prevTasks = recentTasks;
Log.d("Thread", "Inside Thread");
while (true) {
try {
String topPackageName = "";
if(Build.VERSION.SDK_INT >= 21) {
UsageStatsManager mUsageStatsManager = (UsageStatsManager) context.getSystemService("usagestats");
long time = System.currentTimeMillis();
// We get usage stats for the last 10 seconds
List<UsageStats> stats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, time - 1000*5, time);
if(stats != null) {
SortedMap<Long,UsageStats> mySortedMap = new TreeMap<Long,UsageStats>();
for (UsageStats usageStats : stats) {
mySortedMap.put(usageStats.getLastTimeUsed(),usageStats);
}
if(mySortedMap != null && !mySortedMap.isEmpty()) {
topPackageName = mySortedMap.get(mySortedMap.lastKey()).getPackageName();
}
}
}
else {
topPackageName = actMan.getRunningAppProcesses().get(0).processName;
}
recentTasks = topPackageName;
Thread.sleep(timer);
if (recentTasks.length()==0 || recentTasks.equals(
prevTasks)) {
} else {
if (isAppLocked(recentTasks)) {
Log.d(TAG, "Locked " + recentTasks);
handler.post(new RequestPassword(context, recentTasks));
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
prevTasks = recentTasks;
}
}
class ToastRunnable implements Runnable {
String message;
public ToastRunnable(String text) {
message = text;
}
@Override
public void run() {
Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
}
}
class RequestPassword implements Runnable {
private Context mContext;
private String pkgName;
public RequestPassword(Context mContext, String pkgName) {
this.mContext = mContext;
this.pkgName = pkgName;
}
@Override
public void run() {
Intent passwordAct = new Intent(context, PasswordActivity.class);
passwordAct.putExtra("PACKAGE_NAME", pkgName);
passwordAct.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_SINGLE_TOP);
this.mContext.startActivity(passwordAct);
}
}
private boolean isAppLocked(String packageName) {
if (packageName.equals(PasswordActivity.lastUnlocked)) {
return false;
}
PasswordActivity.lastUnlocked = null;
DatabaseHelper dbHelper = new DatabaseHelper(context);
SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM locks WHERE package_name=\'"
+ packageName + "\'", null);
boolean isLocked = false;
if (cursor.moveToNext()) {
isLocked = true;
}
cursor.close();
db.close();
dbHelper.close();
return isLocked;
}
}
Now you must call the above code from your service like this:
@Override
public void onCreate() {
handler = new Handler(getMainLooper());
context = getApplicationContext();
launchChecker = new CheckAppLaunchThread(handler, context);
super.onCreate();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
while (true) {
if (!launchChecker.isAlive())
launchChecker.start();
return START_STICKY;
}
}
Warning: Since Oreo, google has restricted background services and you must figure out a way to always keep your service alive. (that is not the scope of this question) for a clue on this, consider scheduling a JobService and a broadcast receiver that would reschedule your service when ever the android kills it.
来源：https://stackoverflow.com/questions/36261909/how-to-make-app-lock-app-in-android