如果已从启动器图标暂停并重新启动，则应用程序将返回到第一活动

Question

Basically, whenever I launch a second activity and pause the application and relaunch app by tapping on its icon in launcher, app does not resumes on second activity but goes back to first activity. On top of that, if I pause the app(view in task manager), which app makes shows whole activity again like really fast(talking in milliseconds) and then continues to task manager.

Manifest file

<uses-permission android:name="android.permission.INTERNET" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    tools:replace="android:icon">
    <activity
        android:name=".Activity.MainActivity"
        android:launchMode="singleTask">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Activity.ReferenceActivity"
        android:configChanges="orientation|screenSize" /> <!-- Find a better solution for orientation change -->

    <meta-data
        android:name="preloaded_fonts"
        android:resource="@array/preloaded_fonts" />

    <activity android:name=".Activity.AboutActivity"></activity>
</application>

Since you would have noticed launchMode set to "singleTask", there is a reason behind it. My app contains recycler view. Its data is updated from second activity. Without launchMode set to singleTask, recyclerview data is not updated so to update the data I had to relaunch whole app just to see any data change. It is a temporary workaround but I am hoping if someone would help me on this matter as well.

About reycler view not updating, I have asked about that question countless times but never got a solution. Yes, I have gone through probably hundreds of similar problems on stack over flow and none of them work. Please bear in mind that I am beginner in Android development hence I do not have knowledge on advanced things like MvvM, RxJava or live data architecture.

PS Just so any one gives a solution that I recall my data loader function again somewhere in onStart or on Resume, I have tried that countless times and it does not works. My app is not using fragments or any other advanced stuff just basic activities. Any help is appreciated!

Second activity

class ReferenceActivity : AppCompatActivity() {

private var dbHandler: PediaDatabase? = null
private var note = UserNotes()
private var noteExisted: Boolean = false
private var cardAdapterPos: Int? = null
private var title: String? = null
private var text: String? = null
private var sharingMenuOpened: Boolean = false

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_reference)


    val toolbarRef: Toolbar = findViewById(R.id.toolbarRefID)
    setSupportActionBar(toolbarRef)

    val toolbarTxtView = findViewById<TextView>(R.id.refToolbarTitleID)
    supportActionBar!!.setDisplayShowTitleEnabled(false)

    overridePendingTransition(R.anim.slide_in, R.anim.slide_out)




    dbHandler = PediaDatabase(this)
    val data = intent
    if (!isNewNote) {
        window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN)

        if (data != null) {
            noteExisted = true

            this.cardAdapterPos = data.extras.getInt("cardPosition")
            cardID = data.extras.getInt("cardID")


            existingNote = dbHandler!!.readNote(cardID)

            text = existingNote.noteText
            title = existingNote.noteTitle

            refTitleID.setText(existingNote.noteTitle, TextView.BufferType.EDITABLE)
            refTextID.setText(existingNote.noteText, TextView.BufferType.EDITABLE)
            toolbarTxtView.text = "Created: " + existingNote.noteDate.toString()



        }
    } else {
        toolbarTxtView.text = "New note"

        window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE)
    }
}

override fun onResume() {
    super.onResume()
    sharingMenuOpened = false
}


override fun onPause() {
    super.onPause()

    if (!sharingMenuOpened)
        saveNote()
}


override fun onCreateOptionsMenu(menu: Menu?): Boolean {

    menuInflater.inflate(R.menu.top_menu, menu)
    val addItem: MenuItem = menu!!.findItem(R.id.add_note_menu)
    val delItem: MenuItem = menu.findItem(R.id.delete_note_menu)
    val shareButton: MenuItem = menu.findItem(R.id.shareID)


    addItem.isVisible = false
    delItem.isVisible = false
    shareButton.isVisible = false

    if (noteExisted) {
        delItem.isVisible = true
        shareButton.isVisible = true
    }

    return true
}

override fun onOptionsItemSelected(item: MenuItem?): Boolean {

    if (item!!.itemId == R.id.delete_note_menu) {

        val deletionMsg = SweetAlertDialog(this, SweetAlertDialog.WARNING_TYPE)
        deletionMsg.titleText = "Delete this note?"
        deletionMsg.confirmText = "Yes"
        deletionMsg.setCancelable(false)



        deletionMsg.setConfirmClickListener(object : SweetAlertDialog.OnSweetClickListener {
            override fun onClick(sweetAlertDialog: SweetAlertDialog?) {

                dbHandler!!.deleteNote(cardID)


                deletionMsg.dismissWithAnimation()

                val successMsg = SweetAlertDialog(this@ReferenceActivity, SweetAlertDialog.SUCCESS_TYPE)
                successMsg.setCancelable(false)
                successMsg.titleText = "Note deleted!"

                successMsg.setConfirmClickListener(object : SweetAlertDialog.OnSweetClickListener {
                    override fun onClick(sweetAlertDialog: SweetAlertDialog?) {

                        successMsg.dismissWithAnimation()
                        finish()
                    }

                }).show()
            }
        })

        deletionMsg.setCancelButton("No", object : SweetAlertDialog.OnSweetClickListener {
            override fun onClick(sweetAlertDialog: SweetAlertDialog?) {
                deletionMsg.dismissWithAnimation()
            }
        })
        deletionMsg.show()



    }

    if (item.itemId == R.id.shareID) {

        var sharingTitle: String = title!!.trim()
        var sharingText: String = text!!.trim()

        sharingMenuOpened = true

        val sharingIntent = Intent(android.content.Intent.ACTION_SEND)
        sharingIntent.type = "text/plain"
        val shareBody: String? = sharingText
        sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, sharingTitle)
        sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody)
        startActivity(Intent.createChooser(sharingIntent, "Share to"))
    }

    return super.onOptionsItemSelected(item)
}

private fun saveNote() {
    title = refTitleID.text.toString().trim()
    text = refTextID.text.toString().trim()


    if (existingNote.noteText == text && existingNote.noteTitle == title) {
        finish()
    } else {

        if (noteExisted) {

            if (TextUtils.isEmpty(title) && TextUtils.isEmpty(text)) {
                dbHandler!!.deleteNote(cardID)

                val parsedColor = Color.parseColor("#263238")
                Toasty.Config.getInstance().setInfoColor(parsedColor).apply()
                Toasty.info(this, "Note deleted", Toast.LENGTH_SHORT, true).show()
            } else {

                if (TextUtils.isEmpty(title))
                    title = "No title"

                existingNote.noteTitle = title
                existingNote.noteText = text
                existingNote.noteDate = System.currentTimeMillis().toString()

                dbHandler!!.updateNote(existingNote)
                Toasty.success(this, "Note saved", Toast.LENGTH_SHORT, true).show()


                startActivity(Intent(this, MainActivity::class.java))
                finish()
            }

        } else {
            if (TextUtils.isEmpty(title) && TextUtils.isEmpty(text)) {
                finish()
            } else {
                if (TextUtils.isEmpty(title))
                    title = "No title"

                note.noteTitle = title
                note.noteText = text
                note.noteDate = System.currentTimeMillis().toString()

                dbHandler!!.createNote(note)
                Toasty.success(this, "Note saved", Toast.LENGTH_SHORT, true).show()


                startActivity(Intent(this, MainActivity::class.java))
                finish()
            }
        }
    }
}

}

Answer 1

You can try use this in MainActivty:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    if (Intents.isActivityExpandedFromLauncherIcon(this)) {
        finish()
    } else {
        setContentView(R.layout.activity_main)
}
}

upd:

public class Intents {

public static boolean isActivityExpandedFromLauncherIcon(@NonNull Activity activity) {
    return !activity.isTaskRoot() && isActivityStartedFromLauncherIcon(activity.getIntent());
}

public static boolean isActivityStartedFromLauncherIcon(@Nullable Intent intent) {
    return intent != null &&
            intent.hasCategory(Intent.CATEGORY_LAUNCHER) &&
            intent.getAction() != null &&
            intent.getAction().equals(Intent.ACTION_MAIN);
}

}

Answer 2

You are invoking finish() in saveNote() method, which is being called in onPause() , hence every time your app goes into background, current activity is being finished (closed) due to invokation of finish() in it.

Remove the calls to finish() in saveNote() method, and you will be resumed to your current activity instead of landing on launcher/Main Activity.