我试图在我的应用程序上实现无尽的列表视图，但我得到了NullPointerException ...
有人可以帮助我吗？
活动致电课程onCreate
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fretes_proximos);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
this.FormataActionBar();
ListView list = (ListView) findViewById(R.id.list);
//Calling the function with the infinte scroll
list.setOnScrollListener(new EndlessScrollListener() {
@Override
public void onLoadMore(int page, int totalItemsCount) {
// TODO Auto-generated method stub
PopulateListView(page);
}
});
}
PopulateListView方法
private void PopulateListView(int page) {
if (manager != null) {
//Here i'm calling a webservice to populate data
manager.setFretes(FreteDAL.GetFretesAutoList(page));
}
}
EndlessScrollListener CLASS
package com.polifrete.polifreteclass;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
public abstract class EndlessScrollListener implements OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 15;
// The current offset index of data you have loaded
private int currentPage = 0;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
public EndlessScrollListener(int visibleThreshold, int startPage) {
this.visibleThreshold = visibleThreshold;
this.startingPageIndex = startPage;
this.currentPage = startPage;
}
// This happens many times a second during a scroll, so be wary of the code
// you place here.
// We are given a few useful parameters to help us work out if we need to
// load some more data,
// but first we check if we are waiting for the previous load to finish.
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
// If there are no items in the list, assume that initial items are
// loading
if (!loading && (totalItemCount < previousTotalItemCount)) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) {
this.loading = true;
}
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the
// current page
// number and total item count.
if (loading) {
if (totalItemCount > previousTotalItemCount) {
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to
// fetch the data.
if (!loading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// Don't take any action on changed
}
}
LOGCAT OUTPUT
05-21 11:01:38.787: E/AndroidRuntime(30046): FATAL EXCEPTION: main
05-21 11:01:38.787: E/AndroidRuntime(30046): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.polifrete.polifreteandroid/com.polifrete.polifreteandroid.FretesProximosActivity}: java.lang.NullPointerException
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread.access$700(ActivityThread.java:134)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.os.Handler.dispatchMessage(Handler.java:99)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.os.Looper.loop(Looper.java:137)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread.main(ActivityThread.java:4867)
05-21 11:01:38.787: E/AndroidRuntime(30046): at java.lang.reflect.Method.invokeNative(Native Method)
05-21 11:01:38.787: E/AndroidRuntime(30046): at java.lang.reflect.Method.invoke(Method.java:511)
05-21 11:01:38.787: E/AndroidRuntime(30046): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
05-21 11:01:38.787: E/AndroidRuntime(30046): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
05-21 11:01:38.787: E/AndroidRuntime(30046): at dalvik.system.NativeStart.main(Native Method)
05-21 11:01:38.787: E/AndroidRuntime(30046): Caused by: java.lang.NullPointerException
05-21 11:01:38.787: E/AndroidRuntime(30046): at com.polifrete.polifreteandroid.FretesProximosActivity.onCreate(FretesProximosActivity.java:188)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.Activity.performCreate(Activity.java:5047)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
05-21 11:01:38.787: E/AndroidRuntime(30046): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
05-21 11:01:38.787: E/AndroidRuntime(30046): ... 11 more
XML CODE
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/rlTopo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#F2F2F2"
tools:context="com.polifrete.polifreteandroid.FretesProximosActivity$PlaceholderFragment" >
<RelativeLayout
android:id="@+id/rlNrFretes"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/expandirMapa"
android:layout_width="180dp"
android:layout_height="30dp"
android:background="@drawable/botao_vermelho"
android:fontFamily="sans-serif"
android:onClick="btnExibirMapa_OnClick"
android:paddingLeft="10dp"
android:text="@string/exibirMapa"
android:textColor="#FFFFFF"
android:textSize="12sp" />
<ImageView
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_gravity="center_vertical"
android:layout_marginLeft="10dp"
android:contentDescription="@string/localAtual"
android:paddingLeft="10dp"
android:src="@drawable/ic_full_map" />
<Button
android:id="@+id/btnFiltrarBusca"
android:layout_width="100dp"
android:layout_height="30dp"
android:layout_alignParentRight="true"
android:layout_marginRight="10dp"
android:background="@drawable/botao_vermelho"
android:fontFamily="sans-serif"
android:onClick="imgFiltro_OnClick"
android:text="@string/btnFiltrarBusca"
android:textColor="#FFFFFF"
android:textSize="12sp" />
</RelativeLayout>
<RelativeLayout
android:id="@+id/rlLimparFiltro"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/rlNrFretes"
android:paddingTop="5dp"
android:visibility="gone" >
<TextView
android:id="@+id/msgNrFretes"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="sans-serif"
android:gravity="center"
android:paddingLeft="10dp"
android:paddingTop="10dp"
android:text="@string/textView_fretesEncontrados"
android:textSize="13sp" />
<TextView
android:id="@+id/txtFiltroCidade"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/msgNrFretes"
android:fontFamily="sans-serif"
android:paddingLeft="10dp"
android:paddingTop="5dp"
android:textSize="11sp" />
<TextView
android:id="@+id/txtFiltros"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/txtFiltroCidade"
android:fontFamily="sans-serif"
android:paddingLeft="10dp"
android:paddingTop="5dp"
android:textSize="11sp" />
<Button
android:id="@+id/limparFiltro"
android:layout_width="100dp"
android:layout_height="30dp"
android:layout_alignParentRight="true"
android:layout_marginRight="10dp"
android:background="@drawable/botao_vermelho"
android:fontFamily="sans-serif"
android:onClick="btnLimparFiltro_OnClick"
android:text="@string/limparFiltro"
android:textColor="#FFFFFF"
android:textSize="12sp" />
</RelativeLayout>
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/rlLimparFiltro"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="15dp"
android:divider="@android:color/transparent"
android:dividerHeight="10.0dp" >
</ListView>
</RelativeLayout>
更改后的LOGCAT FOT FRAGMENT_FRETES_PROXIMOS
05-21 11:34:45.934: E/FragmentManager(3037): Activity state:
05-21 11:34:47.385: E/AndroidRuntime(3037): FATAL EXCEPTION: main
05-21 11:34:47.385: E/AndroidRuntime(3037): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.polifrete.polifreteandroid/com.polifrete.polifreteandroid.FretesProximosActivity}: java.lang.IllegalArgumentException: No view found for id 0x7f07004e (com.polifrete.polifreteandroid:id/container) for fragment PlaceholderFragment{42078f00 #0 id=0x7f07004e}
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread.access$700(ActivityThread.java:134)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.os.Handler.dispatchMessage(Handler.java:99)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.os.Looper.loop(Looper.java:137)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread.main(ActivityThread.java:4867)
05-21 11:34:47.385: E/AndroidRuntime(3037): at java.lang.reflect.Method.invokeNative(Native Method)
05-21 11:34:47.385: E/AndroidRuntime(3037): at java.lang.reflect.Method.invoke(Method.java:511)
05-21 11:34:47.385: E/AndroidRuntime(3037): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
05-21 11:34:47.385: E/AndroidRuntime(3037): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
05-21 11:34:47.385: E/AndroidRuntime(3037): at dalvik.system.NativeStart.main(Native Method)
05-21 11:34:47.385: E/AndroidRuntime(3037): Caused by: java.lang.IllegalArgumentException: No view found for id 0x7f07004e (com.polifrete.polifreteandroid:id/container) for fragment PlaceholderFragment{42078f00 #0 id=0x7f07004e}
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:919)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:570)
05-21 11:34:47.385: E/AndroidRuntime(3037): at com.polifrete.polifreteandroid.FretesProximosActivity.onStart(FretesProximosActivity.java:231)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1178)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.Activity.performStart(Activity.java:5057)
05-21 11:34:47.385: E/AndroidRuntime(3037): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2065)
05-21 11:34:47.385: E/AndroidRuntime(3037): ... 11 more
我解决了这个问题
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// leave this empty
}
@Override
public void onScrollStateChanged(AbsListView listView, int scrollState) {
if (scrollState == SCROLL_STATE_IDLE) {
if (listView.getLastVisiblePosition() >= listView.getCount() - 1
- threshold) {
currentPage++;
// load more list items:
PopulateListView(currentPage);
}
}
}
private void PopulateListView(final int page) {
final ProgressDialog progress = ProgressDialog.show(
FretesProximosActivity.this, "Aguarde!",
"Carregando fretes...", true);
progress.show();
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
if (manager != null) {
manager.setFretes(FreteDAL.GetFretesAutoList(page));
}
progress.dismiss();
PreencheListView();
}
}, 1000);
}
private void PreencheListView() {
listView = (ListView) findViewById(R.id.list);
List<Frete> fretes = manager.getFretes();
if (fretes != null) {
fretesAll.addAll(fretes);
if (listView.getAdapter() == null) {
FretesListViewAdapter adapter = new FretesListViewAdapter(this,
R.layout.frete_row, fretesAll);
listView.setAdapter(adapter);
} else {
((FretesListViewAdapter) listView.getAdapter()).refill();
}
listView.setOnItemClickListener(this);
}
}
答案 0 :(得分：0)
似乎您没有ID为BEGIN
INSERT INTO
WEB_FE_USER_QUERY(
LISTING_ID ,
QUERY_NAME ,
USER_PREFERENCE ,
USER_CRITERIA ,
DEFAULT_QUERY ,
CREATED_DATE_TIME ,
IS_GLOBAL
)
VALUES(
'0' ,
'NovatedTrades' ,
'test' ,
'test' ,
0 ,
TO_DATE(
'2013-06-14 20:28:16' ,
'YYYY-MM-DD HH24:MI:SS'
) ,
0
);
END;
的视图。所以你试图将片段添加到无处。您需要在片段事务的container方法中指出现有的id。