Question

我正在制作Alarm应用程序，我有3个Tap，并且我想在片段中创建自定义列表视图，但是运行项目时不起作用。谁能告诉我为什么？

这是myAdapter.java

public class myAdapter extends BaseAdapter {

private  Context c;
Fragment fr ;
private int res ;
private ArrayList<Times> test;
public myAdapter(Context c , int res , ArrayList<Times> test)
{
    this.c = c;
    this.res = res;
    this.test = test;

}

@Override
public int getCount() {
    return test.size();
}

@Override
public Times getItem(int position) {
    return test.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if(v == null)
    {
        LayoutInflater.from(c).inflate(res , null , false);
    }

    TextView tv_name = v.findViewById(R.id.textView);
    TextView tv_name2 = v.findViewById(R.id.textView2);

    Times t = getItem(position);
    tv_name.setText(t.getTime());
    tv_name2.setText(t.getDay());
    return v;
}
}

这是Times.java

 public class Alarm extends Fragment {


public Alarm() {
    // Required empty public constructor
}
ListView list;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View v = inflater.inflate(R.layout.fragment_alarm, container, false);;
    list = v.findViewById(R.id.listview);

    ArrayList<Times> names = new ArrayList<>();
    names.add(new Times(1 , 3 , "Am"));
    names.add(new Times(1 , 3 , "Am"));
    names.add(new Times(1 , 3 , "Am"));
    names.add(new Times(1 , 3 , "Am"));
    names.add(new Times(1 , 3 , "Am"));

    myAdapter adapter = new myAdapter(getContext(), R.layout.custom_list_alarm , names);
    Log.e("hi", "onCreateView: " + getContext() );
    list.setAdapter(adapter);



    return v;
}

}

这是Times.java

public class Times {
int id ;

int time ;

String day ;

public Times(int id, int time, String day) {
    this.id = id;
    this.time = time;
    this.day = day;
}

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public int getTime() {
    return time;
}

public void setTime(int time) {
    this.time = time;
}

public String getDay() {
    return day;
}

public void setDay(String day) {
    this.day = day;
}
}

---------崩溃开始 2019-12-07 23：16：10.065 6781-6781 / com.example.myalarm E / Android运行时：致命异常：主要流程：com.example.myalarm，PID：6781 java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法“ android.view.View android.view.View.findViewById（int）” 在com.example.myalarm.myAdapter.getView（myAdapter.java:51）在android.widget.AbsListView.obtainView（AbsListView.java:2362）在android.widget.ListView.makeAndAddView（ListView.java:1970）在android.widget.ListView.fillDown（ListView.java:704）在android.widget.ListView.fillFromTop（ListView.java:765）在android.widget.ListView.layoutChildren（ListView.java:1744）在android.widget.AbsListView.onLayout（AbsListView.java:2161）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）在android.widget.FrameLayout.onLayout（FrameLayout.java:261）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在androidx.viewpager.widget.ViewPager.onLayout（ViewPager.java:1775）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild（HeaderScrollingViewBehavior.java:142）在com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild（ViewOffsetBehavior.java:41）在com.google.android.material.appbar.AppBarLayout $ ScrollingViewBehavior.onLayoutChild（AppBarLayout.java:1556）在androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout（CoordinatorLayout.java:888）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）在android.widget.FrameLayout.onLayout（FrameLayout.java:261）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1741）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1585）在android.widget.LinearLayout.onLayout（LinearLayout.java:1494）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）在android.widget.FrameLayout.onLayout（FrameLayout.java:261）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1741）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1585）在android.widget.LinearLayout.onLayout（LinearLayout.java:1494）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）在android.widget.FrameLayout.onLayout（FrameLayout.java:261）在com.android.internal.policy.DecorView.onLayout（DecorView.java:724）在android.view.View.layout（View.java:17523）在android.view.ViewGroup.layout（ViewGroup.java:5612）在android.view.ViewRootImpl.performLayout（ViewRootImpl.java:2342）在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:2069）在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1246）在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:6301）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:871）在android.view.Choreographer.doCallbacks（Choreographer.java:683）在android.view.Choreographer.doFrame（Choreographer.java:619）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:857）在android.os.Handler.handleCallback（Handler.java:751）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:154）在android.app.ActivityThread.main（ActivityThread.java:6077）在java.lang.reflect.Method.invoke（本机方法）

com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:866） 2019-12-07 23：16：10.065 6781-6781 / com.example.myalarm E / AndroidRuntime：在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:756） 2019-12-07 23：16：10.067 6781-6806 / com.example.myalarm D / EGL_emulation：eglMakeCurrent：0xa7905120：ver 2 0（tinfo 0xa7903230）

片段内的自定义列表视图

0 个答案: