在数组适配器中创建新片段

Question

我有 ListView（在 Fragment 内）填充 arrayAdapter.I 在 listView 的每个视图中都有应用按钮。我为应用按钮做了一个监听器，我想在单击按钮后开始新的片段。我在 getFragmentManager() 得到了 nullPointerException。我已经尝试 , this also 但无法解决我的问题。

这是我的 ArrayAdaptor 代码：

public class FullTimeAdapter extends ArrayAdapter<Datalist> {
    private Context mContext;
    private FullTimeJobs mFragment;
    private List<Datalist> datalists = new ArrayList<>();

    public FullTimeAdapter(@NonNull Context context, ArrayList<Datalist> list) {
        super(context, 0, list);
        mContext = context;
        datalists = list;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull final ViewGroup parent) {
        View listView = convertView;
        if (listView == null) {
            listView = LayoutInflater.from(mContext).inflate(R.layout.full_time_datalist, parent, false);
        }

        Button btnApply = listView.findViewById(R.id.part_btn_apply);
        btnApply.setText("Apply");

        btnApply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Fragment fragment;
                fragment = new Apply();
                FragmentManager fm = fragment.getFragmentManager();
                FragmentTransaction ft = fm.beginTransaction().replace(R.id.container, fragment);
                ft.commit();
            }
        });
        return listView;

    }
}

Logcat:

05-16 17:00:59.566 10150-10150/com.example.innobles.internapp E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.innobles.internapp, PID: 10150
    java.lang.NullPointerException
        at com.example.innobles.internapp.Adapter.FullTimeAdapter.onClick(FullTimeAdapter.java:90)
        at android.view.View.performClick(View.java:4448)
        at android.view.View$PerformClick.run(View.java:18461)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5065)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
        at dalvik.system.NativeStart.main(Native Method)

Answer 1

首先创建一个界面为

interface CustomOnClick {
   void onCustomOnClick();
}

在你应用适配器的片段中实现这个接口，并在你的适配器构造函数中传递你的activity实例在你的适配器中创建接口对象，如

CustomOnClick listener;

并在适配器构造函数中对其进行初始化

public FullTimeAdapter(@NonNull Context context, ArrayList<Datalist> list, CustomOnClick listener) {
        super(context, 0, list);
        this.listener=listener;
        mContext = context;
        datalists = list;
    }

在适配器的 on click 方法中只需编写以下行并将剩余代码移动到 Fragments 的 onCustomClick() 方法中

listener.onCustomClick();

并在您框架的 onCustomClick 方法中使用 getActivity().getFragmentManger()

Answer 2

尝试FragmentManager fm = getActivity().getFragmentManager();

Answer 3

终于可以用了，不知道怎么用..

这是我所做的：

 ((AppCompatActivity) mContext).getSupportFragmentManager().beginTransaction().replace(R.id.container, new Apply()).commit();

而不是

 getActivity().getSupportFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); fragmentTransaction.replace(R.id.container, fragment);
fragmentTransaction.commit();

在数组适配器中创建新片段

create new fragment within array Adapter

android

android-arrayadapter

android-fragments