CODEWITHSUNDEEP
android
user7205862
user7205862

Reputation:

Koltin: Pass Context from inner class

I want to make a toast in the foo method. I have already tried different accesses (see comments). What am I doing wrong?

This didn't work:

class SettingsActivity : AppCompatActivity() {
    companion object{
        fun foo(context : Context){
            Toast.makeText(context, "Bar", Toast.LENGTH_LONG).show()
        }
    }
    private fun createListener() {

        var listener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->   
                foo(this)
                //foo(this.applicationContext)
                //foo(this@SettingsActivity)
            }
    }
}

Working Example:

I could only call Foo if I passed a string instead of context and replaced the toast with a logging object. I called foo in the example with "foo("ttt")":

    //this works:
    fun foo(context : String){
        Log.v("TTTTTT", "QQQQQQQQQQQQ")
    }

There were no errors in the logcat.

Solved: Add lateinit var hi : SettingsActivity in the companion object and fill it before calling foo. Then you can omit the context parameter.

Upvotes: 0

Views: 104

Answers (3)

Kuldeep Saini
Kuldeep Saini

Reputation: 70

Your code seems correct, but just make sure you register the listener to your shared preference

getSharedPreferences("MyPre",Context.MODE_PRIVATE).registerOnSharedPreferenceChangeListen(listener)

Also you can modified your code from

class SettingsActivity : AppCompatActivity() {
companion object{
    fun foo(context : Context){
        Toast.makeText(context, "Bar", Toast.LENGTH_LONG).show()
    }
}
private fun createListener() {

    var listener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->   
            foo(this)
            //foo(this.applicationContext)
            //foo(this@SettingsActivity)
        }
}

}

to

class SettingsActivity : AppCompatActivity() {
companion object{
    fun foo(context : Context){
        Toast.makeText(context, "Bar", Toast.LENGTH_LONG).show()
    }
}
private fun createListener() {

    var listener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->  
           run{
           foo(this)
           }
            }  }}

Upvotes: 0

Shalu T D
Shalu T D

Reputation: 4039

Please try below:

class SettingsActivity : AppCompatActivity() {
    companion object{
        fun foo(context : Context){
            Handler().post {
               Toast.makeText(context, "Bar", Toast.LENGTH_LONG).show()
            }
        }
    }
    private fun createListener() {

        var listener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->   
                foo(this@SettingsActivity)
            }
    }
}

Upvotes: 0

Mr. Patel
Mr. Patel

Reputation: 1385

You'll need to pass context to your companion object for that, inside your activity on create just pass your context to companion object:

class SettingsActivity : AppCompatActivity() {
    companion object{
   var context:Context?=null
        fun foo(context){
            Toast.makeText(context, "Bar", Toast.LENGTH_LONG).show()
        }
    }
override fun onCreate(savedInstanceState: Bundle?) {
  context = this
}
    private fun createListener() {

        var listener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->   
                foo(this)
                //foo(this.applicationContext)
                //foo(this@SettingsActivity)
            }
    }

Upvotes: 0

Related Questions