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Kotlin extension functions to start a generic Activity
package com.pascalwelsch.extensions
import android.app.Activity
import android.content.Context
import android.content.Intent
import android.os.Build
import android.os.Bundle
/**
* Extensions for simpler launching of Activities
*/
inline fun <reified T : Any> Activity.launchActivity(
requestCode: Int = -1,
options: Bundle? = null,
noinline init: Intent.() -> Unit = {}) {
val intent = newIntent<T>(this)
intent.init()
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
startActivityForResult(intent, requestCode, options)
} else {
startActivityForResult(intent, requestCode)
}
}
inline fun <reified T : Any> Context.launchActivity(
options: Bundle? = null,
noinline init: Intent.() -> Unit = {}) {
val intent = newIntent<T>(this)
intent.init()
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
startActivity(intent, options)
} else {
startActivity(intent)
}
}
inline fun <reified T : Any> newIntent(context: Context): Intent =
Intent(context, T::class.java)
@wajahatkarim3
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wajahatkarim3 commented Feb 27, 2018

Usage

class OtherActivity: Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        //...
        userList.clickListener { user ->

            // super simple, no arguments for simple Activities but doesn't prevent a crash for this one
            launchActivity<UserDetailActivity>()

            // add the required argument
            launchActivity<UserDetailActivity> {
                putExtra(INTENT_USER_ID, user.id)
            }

            // add custom flags
            launchActivity<UserDetailActivity> {
                putExtra(INTENT_USER_ID, user.id)
                addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
            }

            // use options for cool animations
            val options = ActivityOptionsCompat.makeSceneTransitionAnimation(this, avatar, "avatar")
            launchActivity<UserDetailActivity>(options = options) {
                putExtra(INTENT_USER_ID, user.id)
            }
            
            // requestCode, why not!?
            launchActivity<UserDetailActivity>(requestCode = 1234) {
                putExtra(INTENT_USER_ID, user.id)
            }
        }
    }
}

@denebchorny
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denebchorny commented Jul 20, 2020

Why do you use startActivityForResult instead of startActivity?

IDK, but would it be good to be able to choose which one to use?

For example, one fun launchActivity and another one fun launchActivityForResult.

What do you think? Or is it right to use alwaysstartActivityForResult?

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