Question

I have an app that use the Google Liense Protection LVL to avoid the access in case license fail I have set to disable buttonNewDoc if the license checking success I must re-enable this.

Unfortunately something doesn’t works.

This is my code:

    public class Home extends Activity {
        private static final String BASE64_PUBLIC_KEY = "mykeywithoutspaces";

        // Generate your own 20 random bytes, and put them here.
        private static final byte[] SALT = new byte[] {
            -00, 00, 30, -2, -58, -57, 00, -64, 51, 32, -95, -45, 13, -6, -36, -15, -11, 32, -64,
            89
        };

        private TextView mStatusText;
        private Button mCheckLicenseButton;

        private LicenseCheckerCallback mLicenseCheckerCallback;
        private LicenseChecker mChecker;
        // A handler on the UI thread.
        private Handler mHandler;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
            setContentView(R.layout.main);

            mStatusText = (TextView) findViewById(R.id.status_text);
buttonNewDoc = (ImageButton) findViewById(R.id.btNewDoc);
        buttonNewDoc.setOnClickListener(mNewDoc);
            mCheckLicenseButton = (Button) findViewById(R.id.check_license_button);
            mCheckLicenseButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View view) {
                    doCheck();
                }
            });

            mHandler = new Handler();

            // Try to use more data here. ANDROID_ID is a single point of attack.
            String deviceId = Secure.getString(getContentResolver(), Secure.ANDROID_ID);

            // Library calls this when it's done.
            mLicenseCheckerCallback = new MyLicenseCheckerCallback();
            // Construct the LicenseChecker with a policy.
            mChecker = new LicenseChecker(
                this, new ServerManagedPolicy(this,
                    new AESObfuscator(SALT, getPackageName(), deviceId)),
                BASE64_PUBLIC_KEY);
            doCheck();
        }

        protected Dialog onCreateDialog(int id) {
            final boolean bRetry = id == 1;
            return new AlertDialog.Builder(this)
                .setTitle(R.string.unlicensed_dialog_title)
                .setMessage(bRetry ? R.string.unlicensed_dialog_retry_body : R.string.unlicensed_dialog_body)
                .setPositiveButton(bRetry ? R.string.retry_button : R.string.buy_button, new DialogInterface.OnClickListener() {
                    boolean mRetry = bRetry;
                    public void onClick(DialogInterface dialog, int which) {
                        if ( mRetry ) {
                            doCheck();
                        } else {
                            Intent marketIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(
                                    "http://market.android.com/details?id=" + getPackageName()));
                                startActivity(marketIntent);                        
                        }
                    }
                })
                .setNegativeButton(R.string.quit_button, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                }).create();
        }

        private void doCheck() {
buttonNewDoc.setEnabled(false);
            mCheckLicenseButton.setEnabled(false);
            setProgressBarIndeterminateVisibility(true);
            mStatusText.setText(R.string.checking_license);
            mChecker.checkAccess(mLicenseCheckerCallback);
        }

        private void displayResult(final String result) {
            mHandler.post(new Runnable() {
                public void run() {
                    mStatusText.setText(result);
                    setProgressBarIndeterminateVisibility(false);
                    mCheckLicenseButton.setEnabled(true);
                }
            });
        }

        private void displayDialog(final boolean showRetry) {
            mHandler.post(new Runnable() {
                public void run() {
                    setProgressBarIndeterminateVisibility(false);
                    showDialog(showRetry ? 1 : 0);
                    mCheckLicenseButton.setEnabled(true);
                }
            });
        }    

        private class MyLicenseCheckerCallback implements LicenseCheckerCallback {
            public void allow(int policyReason) {
                if (isFinishing()) {
                    // Don't update UI if Activity is finishing.
                    return;
                }

                // Should allow user access.
                displayResult(getString(R.string.allow));
buttonNewDoc.setEnabled(false);
            }

            public void dontAllow(int policyReason) {
                if (isFinishing()) {
                    // Don't update UI if Activity is finishing.
                    return;
                }
                displayResult(getString(R.string.dont_allow));
                // Should not allow access. In most cases, the app should assume
                // the user has access unless it encounters this. If it does,
                // the app should inform the user of their unlicensed ways
                // and then either shut down the app or limit the user to a
                // restricted set of features.
                // In this example, we show a dialog that takes the user to Market.
                // If the reason for the lack of license is that the service is
                // unavailable or there is another problem, we display a
                // retry button on the dialog and a different message.
                displayDialog(policyReason == Policy.RETRY);
            }

            public void applicationError(int errorCode) {
                if (isFinishing()) {
                    // Don't update UI if Activity is finishing.
                    return;
                }
                String result = String.format(getString(R.string.application_error), errorCode);
                displayResult(result);
            }
        }

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

    }

And this is the Error:

10-03 14:23:01.469: E/AndroidRuntime(3457): FATAL EXCEPTION: background thread
10-03 14:23:01.469: E/AndroidRuntime(3457): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.ViewRoot.checkThread(ViewRoot.java:3020)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.ViewRoot.invalidateChild(ViewRoot.java:647)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.ViewRoot.invalidateChildInParent(ViewRoot.java:673)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.ViewGroup.invalidateChild(ViewGroup.java:2511)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.View.invalidate(View.java:5279)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at android.view.View.setEnabled(View.java:3151)
10-03 14:23:01.469: E/AndroidRuntime(3457):     at com.myapp.Home$MyLicenseCheckerCallback.allow(Home.java:143)

Answer 1

Instead of mHandler.post, try runOnUiThread for the Runnable objects that need to alter UI components.

Update: The below line of code is what’s causing your problem

public void allow(int policyReason) {
    if (isFinishing()) {
        // Don't update UI if Activity is finishing.
        return;
    }

    // Should allow user access.
    displayResult(getString(R.string.allow));
    buttonNewDoc.setEnabled(false); /* This is the problem line */
}

That statement needs to happen on the UI thread which isn’t happening right now. Making that statement run on the UI thread should fix your problem.

public void allow(int policyReason) {
    if (isFinishing()) {
        // Don't update UI if Activity is finishing.
        return;
    }

    // Should allow user access.
    displayResult(getString(R.string.allow));
    runOnUiThread(new Runnable() {
        public void run() {
            buttonNewDoc.setEnabled(false);
        }
    });
}

You should really rework things so that all UI altering statements are on the main UI thread but this should at least fix your problem.