IllegalStateException Caused By Intent?

Question

I sometimes found java.lang.IllegalStateException in my application:

java.lang.RuntimeException: 
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2825)
  at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2886)
  at android.app.ActivityThread.-wrap12 (ActivityThread.java)
  at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1623)
  at android.os.Handler.dispatchMessage (Handler.java:102)
  at android.os.Looper.loop (Looper.java:186)
  at android.app.ActivityThread.main (ActivityThread.java:6509)
  at java.lang.reflect.Method.invoke (Native Method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:914)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:804)

Caused by: java.lang.IllegalStateException: 
  at com.****.onCreate (***.kt:35) <-- here is the Intent.getStringExtra(..)
  at android.app.Activity.performCreate (Activity.java:6992)
  at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1119)
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2778)

After i looked into it, this issue is caused by Intent.getStringExtra() with code as follows:

private lateinit var mArticle : ArticleModel
private lateinit var mArticleImg : String

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

    val intent : Intent = this.intent;
    mArticleImg = intent.getStringExtra( "articleImg" ) <-- here is where it crashed
    mArticle = intent.getParcelableExtra("data")
}

Have tested this in many testing devices and could not reproduce this crash issue except when i looked into google crash report. What exactly is IllegalStateException and does this happen because of the intent return value?

Answer 1

You may handle possible null value with elvis operator ?:

val intent : Intent = this.intent
mArticleImg = intent.getStringExtra("articleImg") ?: "null-value-fallback"
mArticle = intent.getParcelableExtra("data") ?: "null-value-fallback"

or set the value only if it is not null, e.g. with if or .let{..}:

val intent : Intent = this.intent
intent.getStringExtra("articleImg")?.let { mArticleImg = it }
intent.getParcelableExtra("data")?.let { mArticle = it }

Answer 2

Use these checks to ensure that key is available

if (intent.hasExtra("articleImg")) {    
    mArticleImg = intent.getStringExtra( "articleImg" ) 
}

if (intent.hasExtra("data")) {
    mArticle = intent.getParcelableExtra("data")
}