我知道 OnActivityResult 应该在 Activity 中的 OnResume 之前立即调用,但我不会这样做。我发现它在 OnResume 之前被调用,甚至在 OnStart 之前被调用。下面是我的示例代码,我正在断点相关方法以查看发生了什么。怎么回事?
Activity 一
using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content.PM;
namespace LifecycleTest
{
[Activity(MainLauncher = true)]
public class Activity1 : Activity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.Main);
this.FindViewById<Button>(Resource.Id.button1).Text = "Start Activity 2";
this.FindViewById<Button>(Resource.Id.button1).Click += button_Click;
}
void button_Click(object sender, EventArgs e)
{
Intent i = new Intent(this, typeof(Activity2));
this.StartActivityForResult(i, 1);
}
protected override void OnStop()
{
base.OnStop();
}
protected override void OnResume()
{
base.OnResume();
}
protected override void OnStart()
{
base.OnStart();
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
}
}
}
Activity 2
using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content.PM;
namespace LifecycleTest
{
[Activity]
public class Activity2 : Activity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.Main);
this.FindViewById<Button>(Resource.Id.button1).Text = "Return Result";
this.FindViewById<Button>(Resource.Id.button1).Click += button_Click;
}
void button_Click(object sender, EventArgs e)
{
this.SetResult(Result.Ok);
this.Finish();
}
}
}
布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:minWidth="25px"
android:minHeight="25px">
<Button
android:text="Button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/button1" />
</LinearLayout>
最佳答案
查看 API-23 android.app.ActivityThread#performResumeActivity
它调用#deliverResults()
before doing Activity#performResume()
.
前者最终会调用Activity#onActivityResult()
,而后者如果还没有启动就会调用Activity#onStart()
。因此,调用顺序将是:
onActivityResult()
onStart() // only if it has been stopped
onResume()
从Android 2.0开始似乎都是这样。 .虽然有帖子说claim otherwise .
关于android - OnActivityResult 和 OnResume 的执行顺序,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16340732/