I would like to copy a quite big directory from the assets folder of my app to the data folder on the first run of the app. How do I do that? I already tried some examples, but nothing worked, so I don't have anything. My target is Android 4.2.
我想在app的第一次运行时,把我app的assets文件夹里的一个大目录拷贝到data文件夹里,我该怎么做呢?我已经试过一些例子了,但是没有效果,所以我什么都没有。我的目标是Android 4.2。
Thanks, Yannik
谢谢,Yannik
1 个解决方案
#1
20
try this code of your Application instance (you should write the class in manifest): This code is copying content of assets/files folder to the cache folder of app (you can place other path in copyAssetFolder() function). Only when App is launched for the first time
尝试应用程序实例的这段代码(您应该在manifest中编写类):这段代码将assets/files文件夹的内容复制到app的cache文件夹(您可以在copyAssetFolder()函数中放置其他路径)。只有当应用程序第一次启动时
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.app.Application;
import android.content.Context;
import android.content.res.AssetManager;
import android.preference.PreferenceManager;
public class MyApplication extends Application {
private static Context s_sharedContext;
@Override
public void onCreate () {
super.onCreate();
if (!PreferenceManager.getDefaultSharedPreferences(
getApplicationContext())
.getBoolean("installed", false)) {
PreferenceManager.getDefaultSharedPreferences(
getApplicationContext())
.edit().putBoolean("installed", true).commit();
copyAssetFolder(getAssets(), "files",
"/data/data/com.example.appname/files");
}
}
private static boolean copyAssetFolder(AssetManager assetManager,
String fromAssetPath, String toPath) {
try {
String[] files = assetManager.list(fromAssetPath);
new File(toPath).mkdirs();
boolean res = true;
for (String file : files)
if (file.contains("."))
res &= copyAsset(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
else
res &= copyAssetFolder(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
return res;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
private static boolean copyAsset(AssetManager assetManager,
String fromAssetPath, String toPath) {
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(fromAssetPath);
new File(toPath).createNewFile();
out = new FileOutputStream(toPath);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
return true;
} catch(Exception e) {
e.printStackTrace();
return false;
}
}
private static void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
}
#1
20
try this code of your Application instance (you should write the class in manifest): This code is copying content of assets/files folder to the cache folder of app (you can place other path in copyAssetFolder() function). Only when App is launched for the first time
尝试应用程序实例的这段代码(您应该在manifest中编写类):这段代码将assets/files文件夹的内容复制到app的cache文件夹(您可以在copyAssetFolder()函数中放置其他路径)。只有当应用程序第一次启动时
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.app.Application;
import android.content.Context;
import android.content.res.AssetManager;
import android.preference.PreferenceManager;
public class MyApplication extends Application {
private static Context s_sharedContext;
@Override
public void onCreate () {
super.onCreate();
if (!PreferenceManager.getDefaultSharedPreferences(
getApplicationContext())
.getBoolean("installed", false)) {
PreferenceManager.getDefaultSharedPreferences(
getApplicationContext())
.edit().putBoolean("installed", true).commit();
copyAssetFolder(getAssets(), "files",
"/data/data/com.example.appname/files");
}
}
private static boolean copyAssetFolder(AssetManager assetManager,
String fromAssetPath, String toPath) {
try {
String[] files = assetManager.list(fromAssetPath);
new File(toPath).mkdirs();
boolean res = true;
for (String file : files)
if (file.contains("."))
res &= copyAsset(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
else
res &= copyAssetFolder(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
return res;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
private static boolean copyAsset(AssetManager assetManager,
String fromAssetPath, String toPath) {
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(fromAssetPath);
new File(toPath).createNewFile();
out = new FileOutputStream(toPath);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
return true;
} catch(Exception e) {
e.printStackTrace();
return false;
}
}
private static void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
}