问题
I made a custom file manager, and it is working fine. but it is loading and scrolling very slowly and suddenly there was outofmemory error. I am adding images on the side of the text view
package com.example.fileexplorer;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.Matrix;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class FileExplorer extends Activity {
EditText et;
ListView lv;
ArrayList<Data> list;
ArrayAdapter<Data> aa;
LayoutInflater li;
Context cv=this;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file_explorer);
et = (EditText) findViewById(R.id.et_main);
lv = (ListView) findViewById(R.id.lv_main);
list = new ArrayList<Data>();
readFiles();
li=(LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
aa=new ArrayAdapter<Data>(cv,android.R.layout.simple_list_item_1,list)
{
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Data d=list.get(position);
View v=li.inflate(R.layout.list_inflate, null);
ImageView iv=(ImageView) v.findViewById(R.id.iv_inflate);
TextView tv=(TextView) v.findViewById(R.id.tv_inflate);
Bitmap icon = BitmapFactory.decodeResource(getResources(), d.id);
icon = getdecodedimage(icon, 50, 50);
iv.setImageBitmap(icon);
tv.setText(d.f_name);
tv.setTextColor(Color.BLACK);
return v;
}
};
lv.setAdapter(aa);
}
private void readFiles()
{
File f = new File(Environment.getExternalStorageDirectory().getAbsolutePath());
File[] list_files = f.listFiles();
Data d;
for (int i = 0; i < list_files.length; i++) {
d = new Data();
if (list_files[i].isDirectory()) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.folder;
list.add(d);
}
// Detecting file extentions and giving appropriate image to it
else if (list_files[i].isFile()) {
int temp = (list_files[i].getName().lastIndexOf(".")) + 1;
String extention = list_files[i].getName().substring(temp);
if (extention.equalsIgnoreCase("img") || extention.equalsIgnoreCase("jpg")
|| extention.equalsIgnoreCase("png")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.images;
}
else if (extention.equalsIgnoreCase("mp3") || extention.equalsIgnoreCase("wav")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.music;
}
else if (extention.equalsIgnoreCase("mp4") || extention.equalsIgnoreCase("3gp")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.video;
}
else if (extention.equalsIgnoreCase("doc")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.docx;
}
else if (extention.equalsIgnoreCase("pdf")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.pdf;
}
else if (extention.equalsIgnoreCase("txt")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.txt;
}
else if (extention.equalsIgnoreCase("apk")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.apk;
}
else if (extention.equalsIgnoreCase("xlsx")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.exel;
}
else if (extention.equalsIgnoreCase("pptx")) {
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.pptx;
}
else
{
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.unknown;
}
list.add(d);
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.file_explorer, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_home) {
return true;
}
return super.onOptionsItemSelected(item);
}
class FileHandlingAsync extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
}
}
public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);
// "RECREATE" THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
// Mayur must
// watch.........................................................
// bm.recycle();
// .....................................................................
return resizedBitmap;
}
public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
Bitmap getdecodedimage(Bitmap bmp, int reqWidth, int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 85, byteArrayBitmapStream);
byte[] b = byteArrayBitmapStream.toByteArray();
BitmapFactory.decodeByteArray(b, 0, b.length, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeByteArray(b, 0, b.length, options);
}
}
[![this is the screenshot][1]][1]
The scroll is also very slow, how can I optimize it?
回答1:
Try to use LruCache
This code is working
package com.example.fileexplorer;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.Matrix;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.util.LruCache;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class FileExplorer extends Activity implements OnItemClickListener {
EditText et;
ListView lv;
ArrayList<Data> list;
ArrayAdapter<Data> aa;
LayoutInflater li;
Context cv = this;
String main_path = "/storage";
File[] list_files;
int exit_count = 0; // Double tap back key to exit
ArrayList<Data>list_search;
View v;
private LruCache<Integer, Bitmap> mLrucatche;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file_explorer);
final int maxMemory=(int) (Runtime.getRuntime().maxMemory()/1024);
final int cacheSize=maxMemory/8;
mLrucatche=new LruCache<Integer,Bitmap>(cacheSize){
@Override
protected int sizeOf(Integer key, Bitmap value) {
// TODO Auto-generated method stub
return value.getByteCount()/1024;
}
};
et = (EditText) findViewById(R.id.et_main);
et.setVisibility(View.GONE);
lv = (ListView) findViewById(R.id.lv_main);
list = new ArrayList<Data>();
list_search=new ArrayList<Data>();
lv.setOnItemClickListener(this);
new FileHandlingAsync().execute(main_path);
// readFiles(main_path);
li = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
aa = new ArrayAdapter<Data>(cv, android.R.layout.simple_list_item_1, list) {
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Data d = list.get(position);
v = li.inflate(R.layout.list_inflate, null);
ImageView iv = (ImageView) v.findViewById(R.id.iv_inflate);
TextView tv = (TextView) v.findViewById(R.id.tv_inflate);
Bitmap thumnailImage=null;
// Bitmap icon = BitmapFactory.decodeResource(getResources(), d.id);
// icon = getdecodedimage(icon, 50, 50);
// iv.setImageBitmap(icon);
// Making text short if more than 25 words...only for files
if (d.f_name.length() > 25) {
if (!(list_files[position]).isDirectory()) {
d.f_name = d.f_name.substring(0, 22);
d.f_name = d.f_name + "...";
}
}
tv.setText(d.f_name);
tv.setTextColor(Color.BLACK);
//mayu
int key=d.id;
thumnailImage=getBitmapFromMcache(key);
if(thumnailImage==null)
{
BitmapWorkerTask task=new BitmapWorkerTask(iv);
task.execute(key);
}
iv.setImageBitmap(thumnailImage);
return v;
}
};lv.setAdapter(aa);
//Search feature
et.addTextChangedListener(watcher);
}
public Bitmap getBitmapFromMcache(Integer id)
{
return mLrucatche.get(id);
}
public void addBitmapToMcache(Integer id,Bitmap bitmap)
{
if(getBitmapFromMcache(id)==null)
{
mLrucatche.put(id, bitmap);
}
}
private void readFiles(String path) {
File f = new File(path);
list_files = f.listFiles();
Data d;
for (int i = 0; i < list_files.length; i++) {
d = new Data();
if (list_files[i].isDirectory()) {
String name1=list_files[i].getName();
name1=name1.substring(0, 1);
//Removing directories which starts from "." or "$"
if(name1.equals(".")||name1.equals("$"))
{
}else{
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.folder;
list.add(d);
}
}
// Detecting file extentions and giving appropriate image to it
else if (list_files[i].isFile()) {
int temp = (list_files[i].getName().lastIndexOf(".")) + 1;
String extention = list_files[i].getName().substring(temp);
switch (extention) {
case "img":
case "jpg":
case "jpeg":
case "png": d.f_name = list_files[i].getName().toString();
d.id = R.drawable.images;
break;
case "mp3":
case "wav":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.music;
break;
case "mp4":
case "3gp":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.video;
break;
case "doc":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.docx;
break;
case "pdf":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.pdf;
break;
case "txt":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.txt;
break;
case "apk":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.apk;
break;
case "xlsx":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.exel;
break;
case "pptx":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.pptx;
break;
case "zip":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.zip;
break;
case "rar":
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.rar;
break;
default:
d.f_name = list_files[i].getName().toString();
d.id = R.drawable.unknown;
break;
}
list.add(d);
}
}
}
//For search feature
TextWatcher watcher=new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// TODO Auto-generated method stub
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
};
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
if (list_files[position].isDirectory()) {
Data d = list.get(position);
String name = d.f_name;
main_path = main_path + "/" + name;
ArrayList<Data> temp_list = new ArrayList<Data>();
temp_list.addAll(list);
try {
list.clear();
new FileHandlingAsync().execute(main_path);
// readFiles(main_path);
} catch (Exception e) {
list.addAll(temp_list);
Toast.makeText(cv, "Cannot open", Toast.LENGTH_SHORT).show();
}
aa.notifyDataSetChanged();
} else {
Toast.makeText(cv, "Not a directory", Toast.LENGTH_SHORT).show();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.file_explorer, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_search) {
et.setVisibility(View.VISIBLE);
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
if (!(exit_count == 1)) {
if (!main_path.equals("/storage")) {
int index = main_path.lastIndexOf("/");
main_path = main_path.substring(0, index);
list.clear();
readFiles(main_path);
aa.notifyDataSetChanged();
} else {
exit_count++;
Toast.makeText(cv, "Tap again to exit", Toast.LENGTH_SHORT).show();
}
} else {
System.exit(0);
}
}
class FileHandlingAsync extends AsyncTask<String, Void, Void> {
ProgressDialog pd;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
pd = new ProgressDialog(cv);
pd.setMessage("Getting list of files...");
pd.setCancelable(false);
pd.show();
}
@Override
protected Void doInBackground(String... params) {
// TODO Auto-generated method stub
String m_path = params[0];
readFiles(m_path);
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
aa.notifyDataSetChanged();
pd.dismiss();
}
}
public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);
// "RECREATE" THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
// Mayur must
// watch.........................................................
// bm.recycle();
// .....................................................................
return resizedBitmap;
}
public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
Bitmap getdecodedimage(Bitmap bmp, int reqWidth, int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 85, byteArrayBitmapStream);
byte[] b = byteArrayBitmapStream.toByteArray();
BitmapFactory.decodeByteArray(b, 0, b.length, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeByteArray(b, 0, b.length, options);
}
class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap>
{
private final WeakReference<ImageView> ivReference;
public BitmapWorkerTask(ImageView imageview) {
// TODO Auto-generated constructor stub
ivReference=new WeakReference<ImageView>(imageview);
}
@Override
protected Bitmap doInBackground(Integer... params) {
// TODO Auto-generated method stub
Bitmap bitmap=BitmapFactory.decodeResource(cv.getResources(),params[0]);
addBitmapToMcache(Integer.valueOf(params[0]), bitmap);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
// TODO Auto-generated method stub
if(ivReference!=null || result!=null)
{
final ImageView imageview=(ImageView)ivReference.get();
if(imageview!=null)
{
imageview.setImageBitmap(result);
}
}
}
}
}
hope this helps u
来源：https://stackoverflow.com/questions/33235201/out-of-memory-error-in-file-manager