Question

我有一个PreferenceActivity，我试图在点击偏好时创建一个对话框。我首先尝试将我的DialogPreference类（MyPreferencefragment）保留在PreferenceActivity类之外，并且布局是

  <com.example.second.MyPreferencefragment
    android:dialogMessage="Demo"
    android:key="resetDialog"
    android:negativeButtonText="No"
    android:persistent="false"
    android:positiveButtonText="Yes"
    android:summary="Place the time here"
    android:title="Demo App"  />

这很好但我的对话框有一个按钮，点击它我需要打开一个片段。怎么能实现这一目标？我在Dialogpreference中没有FragmentManager。

我尝试在PreferenceActivity中创建DialogPreference作为内部类，但对话框首选项的布局如下：

 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">


     <DialogPreference class = "com.example.second.PrefsActivity$MyPreferencefragment"
    android:dialogMessage="Demo"
    android:key="resetDialog"
    android:negativeButtonText="No"
    android:persistent="false"
    android:positiveButtonText="Yes"
    android:summary="Place the time here"
    android:title="Demo App"  />

这会引发异常

    Caused by: java.lang.InstantiationException: can't instantiate class android.preference.DialogPreference
  01-15 05:54:01.427: E/AndroidRuntime(12843):  at java.lang.reflect.Constructor.constructNative(Native Method)

这是没用的，因为DialogPreference是一个抽象类。

我只需要在对话框首选项上点击按钮即可启动片段。怎么能实现这一目标？任何建议都会有所帮助。提前谢谢。

编辑::添加整个堆栈

01-15 05:27:41.325: E/AndroidRuntime(8932): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.second/com.example.second.PrefsActivity}: android.view.InflateException: Binary XML file line #5: Error inflating class java.lang.reflect.Constructor
01-15 05:27:41.325: E/AndroidRuntime(8932):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2253)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2311)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.ActivityThread.access$700(ActivityThread.java:152)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1438)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.os.Handler.dispatchMessage(Handler.java:102)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.os.Looper.loop(Looper.java:158)
  01-15 05:27:41.325: E/AndroidRuntime(8932):   at android.app.ActivityThread.main(ActivityThread.java:5236)
  01-15 05:27:41.325: E/AndroidRuntime(8932):   at java.lang.reflect.Method.invokeNative(Native Method)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at java.lang.reflect.Method.invoke(Method.java:515)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1257)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1073)
01-15 05:27:41.325: E/AndroidRuntime(8932):     at dalvik.system.NativeStart.main(Native Method)
 01-15 05:27:41.325: E/AndroidRuntime(8932): Caused by: android.view.InflateException: Binary XML file line #5: Error inflating class java.lang.reflect.Constructor
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.createItem(GenericInflater.java:397)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.onCreateItem(GenericInflater.java:417)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.createItemFromTag(GenericInflater.java:428)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.rInflate(GenericInflater.java:481)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.inflate(GenericInflater.java:326)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.inflate(GenericInflater.java:263)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:272)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1778)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at com.example.tapholdcustom.PrefsActivity.onCreate(PrefsActivity.java:38)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.Activity.performCreate(Activity.java:5389)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2217)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    ... 11 more
  01-15 05:27:41.325: E/AndroidRuntime(8932): Caused by: java.lang.InstantiationException: can't instantiate class android.preference.DialogPreference
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at java.lang.reflect.Constructor.constructNative(Native Method)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
 01-15 05:27:41.325: E/AndroidRuntime(8932):    at android.preference.GenericInflater.createItem(GenericInflater.java:383)
01-15 05:27:41.325: E/AndroidRuntime(8932):     ... 22 more

我主要担心的是：

点击首选项打开自定义对话框
单击自定义对话框首选项中的按钮打开片段（自定义对话框首选项中有三个按钮）

我可以通过不使用dialogpreference作为内部类来实现1，因为它给了我上面提到的堆栈跟踪。但我如何实现第二点？

Answer 1

您需要有一个容器（通常是框架布局），然后使用片段事务将片段交换到该容器中。单独的那个例外并不是非常具有描述性的，我不确定你在得到它之前做了什么 - 你至少需要存在的两个参数构造函数才能通过XML使用片段，否则请确保你有一个空的构造函数如果您试图以这种方式调用它（在代码中）。

发布堆栈跟踪的其余部分，应该有一个引起的。

getSupportFragmentManager().beginTransaction().replace(R.id.your_container_id, new YourFragment()).commit();

按钮上的起始片段单击DialogPreference

1 个答案: