android - 无法从 ActivityGroup 中的 ListActivity 显示 AlertDialog

Question

我试图在单击 ListActivity 中的项目时显示 AlertDialog。我的应用程序在 TabActivity 的选项卡下显示 ListActivity，并且 AlertDialog 显示没有问题。 ListActivity(称为 FavouritesActivity)几乎直接来自 Android 文档，具有以下设置:

    lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {

                //... code to set the strings station, number, route, and direction

                FavouritesActivity.this.confirmSend(position);
            }
        });

然后

public void confirmSend(final int position) {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage("Are you sure?")
        .setCancelable(true)
        .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    //... some code to run here                                                              
                }
            })
        .setNegativeButton("No", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.cancel();
                }
            });
    AlertDialog alert = builder.create();
    alert.show();
}

但是，在 TabActivity 的第二个选项卡中，我有一个使用 LocalActivityManager 启动另一个 ListActivity 的 ActivityGroup，就像这样(同样，与在线选项卡下嵌套列表的教程几乎没有变化):

public class MyGroupActivity extends ActivityGroup {

// Keep this in a static variable to make it accessible for all the nesten activities, lets them manipulate the view                                      
public static MyGroupActivity group;

// Need to keep track of the history if you want the back-button to work properly, don't use this if your activities requires a lot of memory.            
private ArrayList<View> history;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.history = new ArrayList<View>();
    group = this;

    // Start the root activity withing the group and get its view                                                                                         
    View view = getLocalActivityManager().startActivity("FirstListActivity", new
                                                        Intent(this,FirstListActivity.class)
                                                        .addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP))
        .getDecorView();

    // Replace the view of this ActivityGroup                                                                                                             
    replaceView(view);

}

public void replaceView(View v) {
    // Changes this Groups View to the new View.                                                                                                          
    setContentView(v);
}

这里的 FirstListActivity 是一个 ListActivity，它是一个系列中的第一个。用户选择一个项目并呈现另一个 ListActivity，代码如下:

    lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                Intent intent = new Intent();
                intent.setClass(FirstListActivity.this, TheNextListActivity.class);                                                                                                                

                // Create View using the Group Activity's LocalActivityManager                                                                            
                View newview = MyGroupActivity.group.getLocalActivityManager()
                    .startActivity("show_routes", intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP))
                    .getDecorView();
                // And replace the view                                                                                                                   
                MyGroupActivity.group.replaceView(newview);
            }
        });

本系列中的最后一个 ListActivity 与我展示的第一个 ListActivity 示例(确实有效的那个)具有完全相同的 onItemClick 监听器和关联的 confirmSend 函数，但是现在当用户单击某个项目时，AlertDialog 无法显示并且应用程序意外停止，调试输出如下:

W/WindowManager(  570): Attempted to add application window with unknown token android.os.BinderProxy@4373af30.  Aborting.
D/AndroidRuntime( 1953): Shutting down VM
W/dalvikvm( 1953): threadid=3: thread exiting with uncaught exception (group=0x4000fe70)
E/AndroidRuntime( 1953): Uncaught handler: thread main exiting due to uncaught exception
E/AndroidRuntime( 1953): android.view.WindowManager$BadTokenException: Unable to add window -- token android.app.LocalActivityManager$LocalActivityRecord@43750f98 is not valid; is your activity running?
E/AndroidRuntime( 1953):    at android.view.ViewRoot.setView(ViewRoot.java:425)
E/AndroidRuntime( 1953):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:178)
E/AndroidRuntime( 1953):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
E/AndroidRuntime( 1953):    at android.view.Window$LocalWindowManager.addView(Window.java:392)
E/AndroidRuntime( 1953):    at android.app.Dialog.show(Dialog.java:231)
E/AndroidRuntime( 1953):    at com.ttcsms.LastListActivity.confirmSend(LastListActivity.java:119)
E/AndroidRuntime( 1953):    at com.ttcsms.LastListActivity$1.onItemClick(LastListActivity.java:66)
E/AndroidRuntime( 1953):    at android.widget.AdapterView.performItemClick(AdapterView.java:283)
E/AndroidRuntime( 1953):    at android.widget.ListView.performItemClick(ListView.java:3132)
E/AndroidRuntime( 1953):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:1620)
E/AndroidRuntime( 1953):    at android.os.Handler.handleCallback(Handler.java:587)
E/AndroidRuntime( 1953):    at android.os.Handler.dispatchMessage(Handler.java:92)
E/AndroidRuntime( 1953):    at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime( 1953):    at android.app.ActivityThread.main(ActivityThread.java:3948)
E/AndroidRuntime( 1953):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 1953):    at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime( 1953):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
E/AndroidRuntime( 1953):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
E/AndroidRuntime( 1953):    at dalvik.system.NativeStart.main(Native Method)
I/Process (  570): Sending signal. PID: 1953 SIG: 3
I/dalvikvm( 1953): threadid=7: reacting to signal 3
I/dalvikvm( 1953): Wrote stack trace to '/data/anr/traces.txt'
I/Process ( 1953): Sending signal. PID: 1953 SIG: 9
I/ActivityManager(  570): Process com.ttcsms (pid 1953) has died.

导致此失败的 AlertDialog 的这两条路由之间有什么区别？它似乎与 AlertDialog.Building(this) 位有关。在 ActivityGroup 中时，它获取了错误的上下文或其他内容。我在网上找到的每个关于此错误的示例都通过在“this”和“getApplicationContext()”之间进行更改来解决，但在这种情况下，这些都不起作用。我尝试了获取上下文的其他变体，但由于我大多是随机猜测，所以我认为最好在这里寻求建议。我应该传递什么上下文，或者还有什么问题？

Answer 1

明白了!实际上这是一个 Android 上下文 问题。

在线:

AlertDialog.Builder builder = new AlertDialog.Builder(this);

您应该传递 TabActivity 的上下文，而不是this，传递可见/主要 Activity 的上下文以显示 Activity 中的任何弹出窗口。

所以，简单的解决方案:

1. 存储 TabActivity 的上下文以供以后在弹出窗口中使用。
2. 在弹出代码中传递 TabActivity 上下文而不是这个。

希望对您有所帮助。干杯:)