我有一个片段视图需要替换另一个片段。
当选择ListFragment项时，通过将Extras传递给活动中的新（或第二）ListFragment，将DetailsFragment替换为另一个ListFragment。我的问题是我得到了“没有找到处理意图的活动{（有额外的）}”。 ListFragment在活动首次启动时工作正常，但是当我将Details活动与另一个ListFragment更新（替换）时，我收到错误。
这是我的第一个Fragment活动，我想我不知道如何在片段之间正确传递Extras。我肯定没有正确使用fragment-manager / transaction类（？）。如果有人能够纠正我的实施，我将非常感激。
更新：我添加了“i.setClass（getActivity（），ListFragment.class）;”对于ListFragment类中的意图，现在Log错误已更改为以下内容：
UPDTATE 2：我纠正了自己对Arguments的意图，因为Devunwired已经消瘦了，现在效果很好。 Thnx Devunwired。我现在唯一的问题是，当按下后退键时，后台堆栈不起作用。更正后的课程如下：
LogCat （更新）：
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.andaero.test/com.andaero.test.fragments.ListFragment}: java.lang.ClassCastException: com.andaero.test.fragments.ListFragment cannot be cast to android.app.Activity
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1739)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
at android.app.ActivityThread.access$500(ActivityThread.java:122)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4123)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassCastException: com.andaero.test.fragments.ListFragment cannot be cast to android.app.Activity
ListFragment类：
public class ListFragment extends android.app.ListFragment {
boolean mDualPane;
int mCurCheckPosition = 0;
protected TextView activityTitle;
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String extStorageDirectory = Environment.getExternalStorageDirectory()
.toString();
File dbfile = new File(extStorageDirectory + "/Andaero/dB/Andaero.db");
SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile, null);
private static final String QUERY_KEY = "QUERY_KEY";
private static final String QUERY_ORDER = "QUERY_ORDER";
private View layout;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
layout = inflater.inflate(R.layout.listview, null);
return layout;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Bundle extras = getActivity().getIntent().getExtras();
Bundle arg = this.getArguments();//**ADDED TO GET THE ARGS
/**
* Get the query string from last activity and pass it to this
* activity-----------------------------------------------------
*/
String q = null;
if (extras != null) {
q = extras.getString(QUERY_KEY);
}
if (arg != null) {
q = (String) (getArguments() != null ? getArguments().getString(
"QUERY_KEY") : 1);
}
loadQuery(q);
}
public void loadQuery(String q) {
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
String qO = getActivity().getIntent().getStringExtra("QUERY_ORDER");
Cursor c = db.rawQuery(q + " ORDER BY `_id` " + qO, null);
setListAdapter(new QueryAdapter(getActivity(), c));
db.close();
} else {
Alerts.sdCardMissing(getActivity());
}
}
public class QueryAdapter extends CursorAdapter {
public QueryAdapter(Context context, Cursor c) {
super(context, c);
LayoutInflater.from(context);
}
@Override
public void bindView(View v, Context context, final Cursor c) {
int tvLabel = c.getColumnIndexOrThrow("label");
String label = c.getString(tvLabel);
final TextView labelTxt = (TextView) v.findViewById(R.id.label);
if (labelTxt != null) {
labelTxt.setText("(" + label + ")");
}
int tvTitle = c.getColumnIndexOrThrow("title");
final String title = c.getString(tvTitle);
TextView titleTxt = (TextView) v.findViewById(R.id.listTitle);
if (titleTxt != null) {
titleTxt.setText(title);
}
int tvDescription = c.getColumnIndexOrThrow("description");
String description = c.getString(tvDescription);
TextView descriptionTxt = (TextView) v.findViewById(R.id.caption);
if (descriptionTxt != null) {
descriptionTxt.setText(description);
}
int tvDate = c.getColumnIndexOrThrow("date");
String date = c.getString(tvDate);
TextView dateTxt = (TextView) v.findViewById(R.id.dateAdded);
if (dateTxt != null) {
dateTxt.setText(date);
}
int tvGoto = c.getColumnIndexOrThrow("gotoURL");
final String gotoURL = c.getString(tvGoto);
TextView gotoTxt = (TextView) v.findViewById(R.id.dummy);
if (gotoTxt != null) {
gotoTxt.setText(gotoURL);
}
gotoTxt.setVisibility(View.GONE);
v.setTag(gotoURL);
final ListView lv = getListView();
lv.setEnabled(true);
lv.setClickable(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View v, int arg2,
long arg3) {
// Create new fragment and transaction
Fragment newFragment = new ListFragment();
FragmentTransaction transaction = getFragmentManager()
.beginTransaction();
// Replace whatever is in the fragment_container view with
// this fragment,
// and add the transaction to the back stack
transaction.replace(R.id.detailFragment, newFragment);
transaction.addToBackStack(null);
String url = "";
url = (String) v.getTag();
int nI = c.getColumnIndexOrThrow("intent");
String intent = c.getString(nI);
Class<?> myIntent = null;
try {
myIntent = Class.forName("com.andaero.test.fragments"
+ intent);
} catch (ClassNotFoundException e) {
Log.e("ERROR", "Class Not Found for new intent!");
e.printStackTrace();
}
int tvTitle = c.getColumnIndexOrThrow("title");
String title = c.getString(tvTitle);
int tvLabel = c.getColumnIndexOrThrow("label");
String label = c.getString(tvLabel);
String queryKey = "SELECT * FROM " + label;
c.close();
db.close();
Bundle args = new Bundle();//**REPLACED THE INTENTS
args.putString("QUERY_KEY", queryKey);
args.putString("KEY_URL", url);
args.putString("KEY_SUBTITLE", title);
args.putString("KEY_LABEL", label);
args.putString("KEY_INTENT", intent);
args.putString("QUERY_ORDER", "ASC");
newFragment.setArguments(args);
// Commit the transaction
transaction.commit();
}
});
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
final View v = LayoutInflater.from(context).inflate(
R.layout.list_item, parent, false);
return v;
}
}
}
答案 0 :(得分：0)
为什么不创建一个在创建片段时传递值的构造函数？看来这就是你要做的事情
答案 1 :(得分：0)
您使用FragmentTransaction将一个Fragment替换为另一个Fragment，但Intent未使用Activity从一个startActivity()传递数据，您走在正确的轨道上实例到另一个像Intent那样。事实上，使用Fragment调用Fragment来指示ListFragment会导致您不想要的各种烟花（如您所见）。
将数据传递给构造函数中的新Fragment是完全可以的，因此您可以为Bundle创建一个构造函数，该构造函数接受您要转发的任何数据参数。另一个选择是将所有“额外内容”设置为新Fragment.setArguments()上的参数，方法是将它们放在Fragment并使用getArguments()。只要您想要访问附加到Bundle的参数，就可以致电Intent以取回相同的onItemClick()。所以基本上，在Bundle args = new Bundle();
args.putString("QUERY_KEY", queryKey);
//...add all the extras to the bundle
newFragment.setArguments(args);
transaction.commit();
方法中替换所有与Fragment有关的代码，而不是：
ListFragment此外，偏离主题，但您可能希望将{{1}}重命名为其他内容，这样您就不必依赖完全限定的程序包名称来区分{{1}}和代码中的平台版本。
HTH