在片段中阅读了很多关于listview的问题和答案之后，我仍然无法在listview中填充数据。
这是我的代码： 的片段：
public class SongViewFragment extends Fragment {
public ArrayList<String> slist;
int temp;
public View rootView;
public SongViewFragment(int pos,ArrayList<String> data) {
slist=data;
temp=pos;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.activity_song_view_fragment, container, false);
//rootview is not null
ListView gv = (ListView) rootView.findViewById(R.id.listView);
//listview exists in xml file.
gv.setAdapter(
new ArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,android.R.id.text1,slist)
);
gv.setEnabled(true);
return rootView;
}
}
activity_song_view_fragment.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/editText"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<ListView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/listView"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginBottom="0dp"
android:layout_marginLeft="0dp"
android:layout_marginTop="0dp"
android:fastScrollAlwaysVisible="false"
android:fastScrollEnabled="true"
android:smoothScrollbar="true"
android:textFilterEnabled="true" />
</LinearLayout>
logcat的：
06-18 23:54:11.970 11931-11931/com.my.testing.app V/dalvikvm﹕ +++ retrieving /system/lib/libmedia_jni.so OnLoad status
06-18 23:54:11.970 11931-11931/com.my.testing.app V/dalvikvm﹕ +++ earlier OnLoad(/system/lib/libmedia_jni.so) okay
06-18 23:54:12.010 11931-11931/com.my.testing.app D/AndroidRuntime﹕ Shutting down VM
06-18 23:54:12.010 11931-11931/com.my.testing.app W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb2c10180)
06-18 23:54:12.010 11931-11931/com.my.testing.app D/AndroidRuntime﹕ procName from cmdline: com.my.testing.app
06-18 23:54:12.010 11931-11931/com.my.testing.app E/AndroidRuntime﹕ in writeCrashedAppName, pkgName :com.my.testing.app
06-18 23:54:12.010 11931-11931/com.my.testing.app D/AndroidRuntime﹕ file written successfully with content: com.my.testing.app StringBuffer : ;com.my.testing.app
06-18 23:54:14.840 12102-12102/com.my.testing.app I/PGA﹕ New SOCKET connection: .my.testing.app (pid 12102, tid 12102)
06-18 23:54:15.640 12102-12102/com.my.testing.app V/dalvikvm﹕ +++ retrieving /system/lib/libmedia_jni.so OnLoad status
06-18 23:54:15.640 12102-12102/com.my.testing.app V/dalvikvm﹕ +++ earlier OnLoad(/system/lib/libmedia_jni.so) okay
06-18 23:54:15.670 12102-12102/com.my.testing.app D/AndroidRuntime﹕ Shutting down VM
06-18 23:54:15.670 12102-12102/com.my.testing.app W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb2c10180)
06-18 23:54:15.670 12102-12102/com.my.testing.app I/Process﹕ Sending signal. PID: 12102 SIG: 9
06-18 23:54:15.670 12102-12102/com.my.testing.app D/AndroidRuntime﹕ procName from cmdline: com.my.testing.app
06-18 23:54:15.670 12102-12102/com.my.testing.app E/AndroidRuntime﹕ in writeCrashedAppName, pkgName :com.my.testing.app
06-18 23:54:15.670 12102-12102/com.my.testing.app D/AndroidRuntime﹕ file written successfully with content: com.my.testing.app StringBuffer : ;com.my.testing.app
06-18 23:54:15.670 12102-12102/com.my.testing.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:394)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsListView.obtainView(AbsListView.java:2012)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1244)
at android.widget.ListView.onMeasure(ListView.java:1155)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at android.view.View.measure(View.java:12723)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1451)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at android.view.View.measure(View.java:12723)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:812)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092)
at android.view.View.measure(View.java:12723)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:825)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:592)
at dalvik.system.NativeStart.main(Native Method)
更新 填写功能 狭缝
public ArrayList<String> fillPlayList(Context c,int k) {
absolutepath = new ArrayList<String>();
msqlist = new ArrayList<String>();
songTitle = new ArrayList<String>();
final Cursor mCursor = c.getContentResolver().query(
MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
new String[]{MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Audio.Media.DATA, MediaStore.Audio.Media.MIME_TYPE}, null, null,
"LOWER(" + MediaStore.Audio.Media.TITLE + ") ASC");
String songs_name = "";
String mAudioPath = "";
if (mCursor.moveToFirst()) {
do {
String file_type = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.MIME_TYPE));
songs_name=mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME));
mAudioPath = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));
HashMap<String, String> song = new HashMap<String, String>();
msqlist.add(songs_name); //song file name
absolutepath.add(mAudioPath);//full file path
MediaMetadataRetriever md = new MediaMetadataRetriever();
md.setDataSource(mAudioPath);
songTitle.add(md.extractMetadata(MediaMetadataRetriever.METADATA_KEY_TITLE));
} while (mCursor.moveToNext());
}
mCursor.close(); //cursor has been consumed so close it
return songTitle;
}
调用fillPlaylist通过构造函数
将数据发送到片段 @Override
public Fragment getItem(int position) {
ArrayList<String> data=new ArrayList<String>();
data=fillPlayList(getContext(),position);
return new SongViewFragment(position,data);
}
答案 0 :(得分：0)
传递给数组适配器的null返回的列表中有fillPlayList()个元素。这解释了NPE。要获得修复帮助，请发布该方法的代码。