How to combine Intent flags in Kotlin

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花落未央 2020-12-05 13:02

I want to combine two intent flags as we do bellow in android

Intent intent = new Intent(this, MapsActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEA         


        
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  • 2020-12-05 13:09

    Explanation:

    The operation that is applied to the flags is a bitwise or. In Java you have the | operator for that.

    As of bitwise operations [in Kotlin], there're no special characters for them, but just named functions that can be called in infix form.

    Source

    Here a list of all bitwise operations for Int and Long

    • shl(bits) – signed shift left (Java's <<)
    • shr(bits) – signed shift right (Java's >>)
    • ushr(bits) – unsigned shift right (Java's >>>)
    • and(bits) – bitwise and (Java's &)
    • or(bits) – bitwise or (Java's |)
    • xor(bits) – bitwise xor (Java's ^)
    • inv() – bitwise inversion (Java's ~)

    Solution:

    So, in your case you only need to call or in between your arguments like so.

    intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TASK or Intent.FLAG_ACTIVITY_NEW_TASK
    
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  • 2020-12-05 13:20

    Try something like following:

    val intent = Intent(this, MapsActivity::class.java)
    intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TASK or Intent.FLAG_ACTIVITY_NEW_TASK
    
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  • 2020-12-05 13:22

    Advanced, Reuseable Kotlin:

    In Kotlin or is the replacement for the Java bitwise or |.

    intent.flags = FLAG_ACTIVITY_NEW_TASK or FLAG_ACTIVITY_CLEAR_TASK
    

    If you plan to use your combination regularly, create an Intent extension function

    fun Intent.clearStack() {
        flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
    }
    

    You can then directly call this function before starting the intent

    intent.clearStack()
    

    If you need the option to add additional flags in other situations, add an optional param to the extension function.

    fun Intent.clearStack(additionalFlags: Int = 0) {
        flags = additionalFlags or Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
    }
    
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