Question

这是我的代码：

package com.test.testing;

import java.io.File;
import java.util.ArrayList;
import java.util.Date;

import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Environment;
import android.text.Editable;
import android.text.TextWatcher;
import android.text.format.DateFormat;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

public class PreviousTrip extends Fragment {
    int i;
    String k = "";

    @Override
    public View onCreateView( LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState ) {
        final RelativeLayout mFrame3 =  (RelativeLayout) inflater.inflate( R.layout.ptrip, container, false );

        File folder = new File(Environment.getExternalStorageDirectory() + "/tc/");
        ListView lv;
        ArrayList<String> FilesInFolder = GetFiles(folder);
        lv = (ListView) mFrame3.findViewById(R.id.lvFiles);

        lv.setAdapter(new ArrayAdapter<String>(this,
            android.R.layout.ptrip, FilesInFolder));

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
                // Clicking on items
             }
        });

        /*File[] filelist = folder.listFiles();
        String[] theNamesOfFiles = new String[filelist.length];
        if (filelist.length > 0) {
            for (i = 0; i < theNamesOfFiles.length; i++) {
                long lastTime = filelist[i].lastModified();
                String dateString = DateFormat.format("MM/dd/yyyy", new Date(lastTime)).toString();
                theNamesOfFiles[i] = filelist[i].getName();
                k = k + String.valueOf(theNamesOfFiles[i]) + " " + dateString + "\n";
            }
            Toast.makeText(getActivity(), k, Toast.LENGTH_SHORT).show();
        }
        else {
            Toast.makeText(getActivity(), "no files", Toast.LENGTH_SHORT).show();
        }*/

        return mFrame3;
    }

    public ArrayList<String> GetFiles(String DirectoryPath) {
        ArrayList<String> MyFiles = new ArrayList<String>();
        File f = new File(DirectoryPath);

        f.mkdirs();
        File[] files = f.listFiles();
        if (files.length == 0)
            return null;
        else {
            for (int i=0; i<files.length; i++) 
                MyFiles.add(files[i].getName());
        }

        return MyFiles;
    }
}

我的ptrip XML看起来像：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:background="@drawable/bginset3" >

    <ListView
        android:id="@+id/lvFiles"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

    </ListView>

</RelativeLayout>

我收到以下错误，我会帮忙解决：

ArrayList<String> FilesInFolder = GetFiles(folder); 错误：The method GetFiles(String) in the type PreviousTrip is not applicable for the arguments (File) 已修复：ArrayList<String> FilesInFolder = GetFiles(folder.toString());

lv.setAdapter(new ArrayAdapter<String>(this, android.R.layout.ptrip, FilesInFolder)); 错误：ptrip cannot be resolved or is not a field

除此之外，我正在尝试在卡片视图中显示每个项目，就像Play商店中的“我的应用”一样：

enter image description here

Answer 1

ArrayList<String> FilesInFolder = GetFiles(folder); 
Error: The method GetFiles(String) in the type PreviousTrip is not applicable for the arguments (File) 
Fixed: ArrayList<String> FilesInFolder = GetFiles(folder.toString());

我建议你使用folder.getName()而不是folder.toString()。

lv.setAdapter(new ArrayAdapter<String>(this, android.R.layout.ptrip, FilesInFolder)); 
Error: ptrip cannot be resolved or is not a field

首先，只有android.R.layout.some_layout是android框架的一部分才能使用some_layout。

如果R.layout.ptrip是您的布局之一，那么您必须在此布局中向构造函数提供id TextView。例如，您的初始化应如下所示：

lv.setAdapter(new ArrayAdapter<String>(this, R.layout.ptrip,
                               R.id.some_textview_inside_layout_ptrip, FilesInFolder));

如果布局文件ptrip中只有TextView，则以下内容不会导致错误：

    lv.setAdapter(new ArrayAdapter<String>(this, R.layout.ptrip, FilesInFolder));

Answer 2

有很多错误。

您对列表视图项使用了错误的布局ptrip。项目布局必须有TextView android:id = "@android:id/text1"才能自动使用ArrayAdapter。

这里有一些改进的代码：

public class PreviousTrip extends Fragment {
    int i;
    String k = "";

    @Override
    public View onCreateView( LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState ) {
        final RelativeLayout mFrame3 =  (RelativeLayout) inflater.inflate( R.layout.ptrip, container, false );
        final ListView lv = (ListView) mFrame3.findViewById(R.id.lvFiles);

        final File directory = new File(Environment.getExternalStorageDirectory(), "tc");

        final ArrayList<String> files = GetFiles(directory);

        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,files);

        lv.setAdapter(adapter);

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
                // Clicking on items
            }
        });

        return mFrame3;
    }

    public ArrayList<String> GetFiles(File directory) {
        ArrayList<String> files = new ArrayList<String>();

        directory.mkdirs();

        if(!directory.exists()){return files;}

        File[] fileArray = directory.listFiles();
        for (int i=0; i<fileArray.length; i++){
            files.add(fileArray[i].getName());
        }

        return files;
    }
}

ListView在显示目录中的文件时出错

2 个答案: