0
我在對話框片段中設置了搜索字段，然後當用戶最初單擊打開時，允許他們輸入標題並點擊搜索。我希望這能夠傳達回活動的列表視圖。將數據從DialogFragment傳遞迴活動
不幸的是，當我試圖搜索時，我一直在崩潰。我已經使用偵聽器進行了設置，但我認爲它與嘗試從MainActivity的佈局中讀取textView有關，即使它位於DialogFragment'a佈局xml中？
我嘗試通過MainActivity中的R.id.searchField來調用它，其中onCreate的setContent的佈局XML與DialogFragment實現的不同。試圖這樣做時，我沒有任何錯誤，只是致命的崩潰。不知道爲什麼別的我會收到一個錯誤，下面是代碼，和堆棧跟蹤它下面：
MainActivity：
public class MainActivity extends Activity implements searchListener{
public void searchBooks()
{
// Error is in this function, believe it has to do with this textField as it resides in // the DialogFragment's xml? Unless findViewById calls from all XMLS and just not one defined in
//setContentView for the activity? Not sure though, initially I feel I should have this searchField
//defined in the fragment class, but then I won't have access to it in this function in MainActivity,
//or the mResults which is where the data is being used
EditText searchField = (EditText) findViewById(R.id.searchField);
if (mResults != null && !searchField.getText().equals(""))
{
String inputedText = searchField.getText().toString();
JSONArray results = new JSONArray();
for (int i = 0; i < mResults.length(); i++)
{
try {
JSONObject bookObject = mResults.getJSONObject(i);
if (bookObject.get("name").toString().equalsIgnoreCase(inputedText))
{
results.put(bookObject);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
public void showDialog() {
DialogFrag newFragment = DialogFrag.newInstance();
newFragment.show(getFragmentManager(), "dialog");
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Setting the main view
setContentView(R.layout.activity_main_fragment);
}
}
DialogFragment：
public class DialogFrag extends DialogFragment {
public static DialogFrag newInstance() {
return new DialogFrag();
}
private searchListener listener;
public interface searchListener
{
public void searchBooks();
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
listener = (searchListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + "attaching d fragment failed!");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.search_dialog_fragment, container, false);
searchButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
listener.searchBooks();
}
});
return v;
}
}
堆棧跟蹤
01-29 20:10:21.570: E/AndroidRuntime(11260): FATAL EXCEPTION: main
01-29 20:10:21.570: E/AndroidRuntime(11260): Process: com.brentadams.bookList, PID: 11260
01-29 20:10:21.570: E/AndroidRuntime(11260): java.lang.NullPointerException
01-29 20:10:21.570: E/AndroidRuntime(11260): at com.brentadams.bookList.MainActivity.searchBooks(MainActivity.java:327)
01-29 20:10:21.570: E/AndroidRuntime(11260): at com.brentadams.bookList.fragments.SearchFragment$1.onClick(SearchFragment.java:48)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.view.View.performClick(View.java:4438)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.view.View$PerformClick.run(View.java:18422)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.os.Handler.handleCallback(Handler.java:733)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.os.Handler.dispatchMessage(Handler.java:95)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.os.Looper.loop(Looper.java:136)
01-29 20:10:21.570: E/AndroidRuntime(11260): at android.app.ActivityThread.main(ActivityThread.java:5017)
01-29 20:10:21.570: E/AndroidRuntime(11260): at java.lang.reflect.Method.invokeNative(Native Method)
01-29 20:10:21.570: E/AndroidRuntime(11260): at java.lang.reflect.Method.invoke(Method.java:515)
01-29 20:10:21.570: E/AndroidRuntime(11260): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-29 20:10:21.570: E/AndroidRuntime(11260): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-29 20:10:21.570: E/AndroidRuntime(11260): at dalvik.system.NativeStart.main(Native Method)
編輯新代碼/錯誤：
接受了您的建議，並將字符串傳回方法searchBooks，但現在接受了我認爲沒有任何意義的愚蠢nullpointerexception。 TextView的駐留在我的activity_main_fragment.xml：
public class MainActivity extends Activity implements searchListener{
public void searchBooks(String searchString)
{
if (mResults != null && searchString != null && !searchString.equals(""))
{
JSONArray results = new JSONArray();
for (int i = 0; i < mResults.length(); i++)
{
try {
JSONObject bookObject = mResults.getJSONObject(i);
if (bookObject.get("name").toString().equalsIgnoreCase(searchString))
{
results.put(bookObject);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
public void showDialog() {
DialogFrag newFragment = DialogFrag.newInstance();
newFragment.show(getFragmentManager(), "dialog");
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Setting the main view
setContentView(R.layout.activity_main_fragment);
}
}
DialogFragment
public class DialogFrag extends DialogFragment {
public static DialogFrag newInstance() {
return new DialogFrag();
}
private searchListener listener;
public interface searchListener
{
public void searchBooks(String text);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
listener = (searchListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + "attaching d fragment failed!");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.search_dialog_fragment, container, false);
searchButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
EditText searchField = (EditText) v.findViewById(R.id.searchField);
String input = searchField.getText().toString();
listener.searchBooks(input);
}
});
return v;
}
}
堆棧跟蹤
01-29 15:30:31.402: E/AndroidRuntime(777): FATAL EXCEPTION: main
01-29 15:30:31.402: E/AndroidRuntime(777): java.lang.NullPointerException
01-29 15:30:31.402: E/AndroidRuntime(777): at com.brentadams.bookList.fragments.SearchFragment$1.onClick(SearchFragment.java:51)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.view.View.performClick(View.java:4084)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.view.View$PerformClick.run(View.java:16966)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.os.Handler.handleCallback(Handler.java:615)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.os.Handler.dispatchMessage(Handler.java:92)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.os.Looper.loop(Looper.java:137)
01-29 15:30:31.402: E/AndroidRuntime(777): at android.app.ActivityThread.main(ActivityThread.java:4745)
01-29 15:30:31.402: E/AndroidRuntime(777): at java.lang.reflect.Method.invokeNative(Native Method)
01-29 15:30:31.402: E/AndroidRuntime(777): at java.lang.reflect.Method.invoke(Method.java:511)
01-29 15:30:31.402: E/AndroidRuntime(777): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-29 15:30:31.402: E/AndroidRuntime(777): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-29 15:30:31.402: E/AndroidRuntime(777): at dalvik.system.NativeStart.main(Native Method)
線51：
String input = searchField.getText().toString();
張貼堆棧跟蹤 – Raghunandan
張貼它感謝您花時間看！ – user3117785
什麼是第327行'MainActivity.java'？ – Raghunandan