Question

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                + WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD|
                + WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED|
                + WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
        setContentView(R.layout.activity_main);
        PowerManager.WakeLock wl;
        PowerManager pm = (PowerManager) getSystemService(
                Context.POWER_SERVICE);
        wl = pm.newWakeLock(
                PowerManager.PARTIAL_WAKE_LOCK
                        | PowerManager.ACQUIRE_CAUSES_WAKEUP,
                "ToastActivity");
        wl.acquire();
        Log.w("TOAST","show");
        Toast.makeText(this, "test toast", Toast.LENGTH_LONG).show();
    }

In the above code I have made my Activity to Launch when the screen is security locked(pin/swipe) too.

However the Toast message is not displayed while its launched when the phone is security locked.

When I unlock the device and launch again, the toast message is seen.

Initially I tried without the WAKE_LOCK changes, it did not work. Then I tried with WAKE_LOCK changes too, still it did not work.

How to fix this issue. Is this an Android limitation?.

Answer 1

Toast无法在锁定屏幕上显示。

从Android版本5.0开始，锁定屏幕小部件也有gone extinct。

最好的办法是使用Notification，如下所示：

            Notification.Builder builder = new Notification.Builder(mContext)
                    .setContentTitle("Alert message here")
                    .setSmallIcon(R.drawable.alert) //required, otherwise throws 'no valid small icon)'
                    .setVisibility(NotificationCompat.VISIBILITY_PUBLIC); //viewable on lock-screen

            NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            nm.notify("test", 0, builder.build());

您还可以添加触发意图的按钮。

Unable to display Toast message when phone is PIN locked

1 个答案: