Question

我使用了android studio附带的标准片段，因为我认为它会简化我的工作，因为我还在学习java。但由于内部代码太多，我已经迷失了，不知道事情是如何运作的。活动我似乎理解基础知识，但在一些研究之后，活动和片段之间存在很大差异

我正在尝试应用我在片段活动中学到的相同原理，但似乎不可能。它说我想用一个inflater覆盖oncreateview但我似乎不理解背后的概念，为什么我不能使用简单的setcontentview并从imageview和textedit检索内容？是否有解决方法或者我最好避免碎片？

    package com.venomdev.safestorage;

import android.app.Activity;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link EncryptFiles.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link EncryptFiles#newInstance} factory method to
 * create an instance of this fragment.
 *
 */
public class EncryptFiles extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    ImageView UploadFile;
    Button bUpload;
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment EncryptFiles.
     */
    // TODO: Rename and change types and number of parameters
    public static EncryptFiles newInstance(String param1, String param2) {
        EncryptFiles fragment = new EncryptFiles();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }
    public EncryptFiles() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.UploadFile);

        UploadFile = (ImageView) findViewById(R.id.UploadFile);


        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_encrypt_files, container, false);
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        if (activity instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) activity;
        } else {
            throw new RuntimeException(activity.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

Answer 1

因为Fragment位于Activity内部，并且不能单独使用。您不能将Fragment用作Activity的完全替代，但您可以将Fragment用作Activity的一部分，也可以在其他活动中重复使用。

您需要调用For Each c As Object In Me.components.Components If TypeOf c Is Timer Then CType(c, System.Windows.Forms.Timer).Enabled = False End If Next，因为系统会在片段第一次绘制其用户界面时调用此方法。要为您的片段绘制UI，您必须从此方法返回一个视图，该视图是片段布局的根。如果片段没有提供UI，则可以返回null。

要进一步了解Fragment，您应该阅读official documentation

Answer 2

是的，就像Niko Yuwono在他的回答中提到的那样。你的onCreateView必须是这样的。因此，Ui可以使用java代码进行充气，您可以在屏幕上通过设计处理UI点击和用户的交互。

 public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState)
{

 super.onCreateView(inflater, container, savedInstanceState);
        final View rootview = inflater.inflate(R.layout.fragment_encrypt_files, container, false);
return rootview;
}

您必须在代码中删除Oncreate（）方法，因为这不是Activity。

如何在片段中设置内容视图

2 个答案: