当我关闭第二个活动时，我试图从片段中清除我的主要内容。
我以这种方式调用片段以通过FrameLayout显示在主活动上
override fun onOptionsItemSelected(item: MenuItem): Boolean {
when (item.itemId) {
R.id.action_about -> {
load_about(loaderAboutFragment = AboutFragment())
Toast.makeText(applicationContext,"About the Author", Toast.LENGTH_LONG).show()
}
R.id.action_affiliate -> {
load_affiliate(loaderAffiliateFragment = AffiliateFragment())
Toast.makeText(applicationContext,"Affiliate Disclosure", Toast.LENGTH_LONG).show()
}
R.id.action_terms -> {
load_terms(loaderTermsFragment = TermsFragment())
Toast.makeText(applicationContext,"Terms And Conditions of Use", Toast.LENGTH_LONG).show()
}
else -> return super.onOptionsItemSelected(item)
}
return true
}
// For handling layout / opening Fragment
private fun load_about(loaderAboutFragment: AboutFragment) {
val fm = supportFragmentManager.beginTransaction()
fm.replace(R.id.frameLayout, loaderAboutFragment)
fm.addToBackStack(null)
fm.commit()
}
这是第二次活动
class CentersActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_centers)
//Action Bar Button / Back to Home
supportActionBar!!.setDisplayHomeAsUpEnabled(true)
//Listview of Centers
val regioncenters = resources.getStringArray(R.array.centers_list)
var lv = findViewById<ListView>(R.id.center_content_lview)
val adapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, regioncenters)
lv.adapter = adapter
}
//Listener for Back to Home Button
override fun onOptionsItemSelected(item: MenuItem): Boolean {
when (item.getItemId()) {
android.R.id.home -> {
finish()
setContentView(R.layout.activity_main)
return true
}
}
return super.onOptionsItemSelected(item)
}
}
我该怎么做？我应该在我的主页按钮侦听器上放什么。
在MainActivity中，转到您打开第二活动的意图。而不是
startActivity(intent);
使用
startActivityForResult(intent, REQUEST_CODE); //where req code is a static final integer.
在完成（）之前的秒活动中写：
setResult(RESULT_OK);
现在回到MainActivity。覆盖此方法
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
if (requestCode == REQUEST_CODE) {
if (resultCode == RESULT_OK) {
//this is how you remove one fragment. You might want to extract this in a method (select lines and ctrl+alt+M),and call the method here for each of your fragments' ids.
val fm = fragmentManager().findFragmentById(R.id.fragmentName);
if(fm != null) //this ensures that if a fragment is not open, it will not be closed. Thus avoiding an error
supportFragmentManager()
.beginTransaction()
.remove(fm)
.commit();
}
}
}
