3

我知道 OnActivityResult 应该在 Activity 中的 OnResume 之前立即调用，但这对我来说并没有发生。我发现它在 OnResume 之前被调用，甚至在 OnStart 之前。我的示例代码如下，我正在对相关方法进行断点以查看发生了什么。这是怎么回事？

活动一

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);
        }
    }
}

活动二

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>
4

2 回答 2

8

查看它在执行之前android.app.ActivityThread#performResumeActivity调用的 API-23 。#deliverResults()Activity#performResume()

前者最终会调用Activity#onActivityResult()，而后者将Activity#onStart()在尚未启动时调用。因此，调用顺序将是：

onActivityResult()
onStart() // only if it has been stopped
onResume()

这似乎一直追溯到Android 2.0。尽管有些帖子声称并非如此。

于 2015-11-07T11:26:50.367 回答
1

当您的活动设置为“singleInstance”时会发生这种情况。是您的活动单实例。尝试删除它。

于 2013-05-02T17:35:27.310 回答