你好，
我正在开发一个导入pdf文件的书架应用程序，以便用户可以阅读它们。当您单击导入书籍按钮时，它表示它会导入书籍，但不会查看它们。一旦你关闭应用程序并尝试重新打开它，你就会关闭一个力量。这是logcat所说的：
Unable to decode stream: java.io.FileNotFoundException: /mnt/sdcard/shelf/preview/LittleBookOfRubypdf.png: open failed: ENOENT (No such file or directory)
Unable to decode stream: java.io.FileNotFoundException: /mnt/sdcard/shelf/preview/best_of_ruby_quizpdf.png: open failed: ENOENT (No such file or directory)
我有
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
这是我的书架代码：
package com.sibext.android_shelf;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.List;
import com.d4a.tobias.R;
import com.sibext.android_shelf.adapter.ShelfAdapter;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.Toast;
public class Two extends Fragment{
private static final String TARGET_DIRECTORY = "mnt/sdcard/shelf/";
private ListView list;
Context ctx;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.two, container, false);
this.ctx = view.getContext();
File dir = new File(TARGET_DIRECTORY);
if(!dir.exists()){
dir.mkdirs();
//past here
addBooksFromAssetsToCard();
}else{
String files[] = dir.list();
if(files.length == 0){
//past here
addBooksFromAssetsToCard();
}
}
list = (ListView) view.findViewById(R.id.list);
ShelfAdapter adapter = new ShelfAdapter(view.getContext(), TARGET_DIRECTORY);
adapter.setToListView(list);
return view;
}
public void addBooksFromAssetsToCard(){
List<String> books;
try {
books = getBooksFromAsset(ctx);
for(String book : books){
copyFromAssets(book);
}
} catch (Exception e) {
}
}
public List<String> getBooksFromAsset(Context ctx) throws Exception
{
AssetManager assetManager =ctx.getAssets();
String[] files = assetManager.list("books");
List<String> it=Arrays.asList(files);
return it;
}
public void copyFromAssets(String book)
{
AssetManager assetManager = ctx.getAssets();
String[] files = null;
InputStream in = null;
OutputStream out = null;
//String filename = "filename.ext";
try
{
in = assetManager.open("books/"+book);
out = new FileOutputStream(Environment.getExternalStorageDirectory()+File.separator+"/shelf/"+book);
Log.d("Copying...", ""+book);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
}
catch(Exception e)
{
Log.e("tag", "Failed to copy asset file: " + book, e);
}
}
public void copyFile(InputStream in, OutputStream out) throws Exception
{
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
Log.d("Copy_State", "Done...");
}
/*public void onImportClicked(View v){
Toast.makeText(v.getContext(), "Please wait...", Toast.LENGTH_LONG).show();
Intent in = new Intent(v.getContext(), ImportBooks.class);
startActivity(in);
}*/
}
这是导入书籍代码：
package com.sibext.android_shelf;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import com.d4a.tobias.R;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
public class ImportBooks extends Activity {
int index =0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.import_books);
populateTotal();
try {
copybooks();
} catch (Exception e) {
}
}
public void copybooks() throws Exception{
String rootPath = Environment.getExternalStorageDirectory().toString();
List<String> books = fetchToneFiles(getApplicationContext(), rootPath);
String desPath = rootPath+File.separator+"shelf"+File.separator;
for(String book : books){
File file = new File(desPath+fetchBookName(book));
if(!file.exists()){
Log.d("[BOOK_Status]", "--Not Exist in shelf-- :"+book);
File from = new File(book);
File to = new File(desPath+fetchBookName(book));
copyDirectoryOneLocationToAnotherLocation(from, to);
index++;
new Handler().postDelayed(new Runnable() {
public void run() {
//
((TextView) findViewById(R.id.total)).setText(String.valueOf(index));
}
}, 2 * 1000);
}
}
if(index == 0){
Toast.makeText(getApplicationContext(), "No new book found...", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(), "All Books imported successfully...", Toast.LENGTH_LONG).show();
}
new Handler().postDelayed(new Runnable() {
public void run() {
//Intent in = new Intent(getApplicationContext(), MainActivity_old.class);
//startActivity(in);
finish();
}
}, 7 * 1000);
}
public void copyDirectoryOneLocationToAnotherLocation(File sourceLocation, File targetLocation)
throws Exception {
if (sourceLocation.isDirectory()) {
if (!targetLocation.exists()) {
targetLocation.mkdir();
}
String[] children = sourceLocation.list();
for (int i = 0; i < sourceLocation.listFiles().length; i++) {
copyDirectoryOneLocationToAnotherLocation(new File(sourceLocation, children[i]),
new File(targetLocation, children[i]));
}
} else {
InputStream in = new FileInputStream(sourceLocation);
OutputStream out = new FileOutputStream(targetLocation);
// Copy the bits from instream to outstream
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
in.close();
out.close();
}
}
public void populateTotal(){
String rootPath = Environment.getExternalStorageDirectory().toString();
List<String> _str = fetchToneFiles(getApplicationContext(), rootPath);
int index = 0;
for(String str : _str){
//Toast.makeText(getApplicationContext(), fetchBookName(str), Toast.LENGTH_LONG).show();
index++;
}
((TextView) findViewById(R.id.imported)).setText(String.valueOf(index));
}
public static List<String> fetchToneFiles(Context ctx, String rootPath) {
final List<String> tFileList = new ArrayList<String>();
String[] imageTypes = {"pdf"};
FilenameFilter[] filter = new FilenameFilter[imageTypes.length];
int i = 0;
for (final String type : imageTypes) {
filter[i] = new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith("." + type);
}
};
i++;
}
FileUtils fileUtils = new FileUtils();
File[] allMatchingFiles = fileUtils.listFilesAsArray(
new File(rootPath), filter, -1);
for (File f : allMatchingFiles) {
tFileList.add(f.getAbsolutePath());
}
return tFileList;
}
public String fetchBookName(String basepath){
String bookname = null;
if(basepath.length()>6){
int index = basepath.lastIndexOf("/");
return basepath.substring(index+1, basepath.length());
}else{
return bookname;
}
}
@Override
public void onBackPressed() {
finish();
super.onBackPressed();
}
}
我的货架物品代码：
package com.sibext.android_shelf.shelf;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import com.artifex.mupdfdemo.MuPDFCore;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PointF;
public class ShelfItem {
private File file;
private String imgPath;
public ShelfItem(File file){
if(file == null){
throw new NullPointerException("Impossible init ShelfItem by null file");
}
this.file = file;
imgPath = file.getName().replace(".", "") + ".png";
createPreviewDir();
}
private void createPreviewDir(){
File dir = new File(getPreviewDir());
if(!dir.exists()){
dir.mkdirs();
}
}
public File getFile() {
return file;
}
private String getPreviewPath(){
return getPreviewDir() + imgPath;
}
private String getPreviewDir(){
return file.getParent() + File.separator + "preview" + File.separator;
}
public void savePreview(Bitmap b){
try {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
File f = new File(getPreviewPath());
f.createNewFile();
FileOutputStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());
fo.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public Bitmap getPreview(int rowHeight){
MuPDFCore core = null;
try {
core = new MuPDFCore(getFile().getAbsolutePath());
} catch (Exception e) {
e.printStackTrace();
}
if(core == null){
return null;
}
core.countPages();
PointF size = core.getPageSize(0);
int h = rowHeight;
int w = (int)(h * (size.x/size.y));
return core.drawPage(0, w, h, 0, 0, w, h);
}
public Bitmap getPreviewFromSD(){
return BitmapFactory.decodeFile(getPreviewPath());
}
}
任何帮助都会很棒 提前致谢
此致
克里斯
答案 0 :(得分：2)
你永远不应该“硬编码”SD路径，因为你可能知道android设备有几个制造商。这些制造商可以自由地定义SD卡的路径（简而言之：/ mnt / sdcard不是每个Android设备上的SD卡路径）
使用内置函数“Environment.getExternalStorageState（）”来获取路径。来自android开发者文档：
Environment.getExternalStorageState（）返回内部SD挂载点的路径，如“/ mnt / sdcard”