以编程方式清除 Android 应用程序中的缓存

在 android 应用程序中清除缓存的正确方法是什么。我已经使用下面的代码,但它看起来不适合我

@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
clearApplicationData();
}


public void clearApplicationData() {
File cache = getCacheDir();
File appDir = new File(cache.getParent());
if (appDir.exists()) {
String[] children = appDir.list();
for (String s : children) {
if (!s.equals("lib")) {
deleteDir(new File(appDir, s));
Log.i("EEEEEERRRRRRROOOOOOORRRR", "**************** File /data/data/APP_PACKAGE/" + s + " DELETED *******************");
}
}
}
}


public static boolean deleteDir(File dir) {
if (dir != null && dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
}
}


return dir.delete();
}

Image from my android phone

171416 次浏览

I think you're supposed to place clearApplicationData() before the super.OnDestroy().

Your app can't process any methods when it has been shut down.

If you are looking for delete cache of your own application then simply delete your cache directory and its all done !

public static void deleteCache(Context context) {
try {
File dir = context.getCacheDir();
deleteDir(dir);
} catch (Exception e) { e.printStackTrace();}
}


public static boolean deleteDir(File dir) {
if (dir != null && dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
}
return dir.delete();
} else if(dir!= null && dir.isFile()) {
return dir.delete();
} else {
return false;
}
}

The answer from dhams is correct (after having been edited several times), but as the many edits of the code shows, it is difficult to write correct and robust code for deleting a directory (with sub-dirs) yourself. So I strongly suggest using Apache Commons IO, or some other API that does this for you:

import org.apache.commons.io.FileUtils;


...


// Delete local cache dir (ignoring any errors):
FileUtils.deleteQuietly(context.getCacheDir());

PS: Also delete the directory returned by context.getExternalCacheDir() if you use that.

To be able to use Apache Commons IO, add this to your build.gradle file, in the dependencies part:

compile 'commons-io:commons-io:2.4'

I am not sure but I sow this code too. this cod will work faster and in my mind its simple too. just get your apps cache directory and delete all files in directory

public boolean clearCache() {
try {


// create an array object of File type for referencing of cache files
File[] files = getBaseContext().getCacheDir().listFiles();


// use a for etch loop to delete files one by one
for (File file : files) {


/* you can use just [ file.delete() ] function of class File
* or use if for being sure if file deleted
* here if file dose not delete returns false and condition will
* will be true and it ends operation of function by return
* false then we will find that all files are not delete
*/
if (!file.delete()) {
return false;         // not success
}
}


// if for loop completes and process not ended it returns true
return true;      // success of deleting files


} catch (Exception e) {}


// try stops deleting cache files
return false;       // not success
}

It gets all of cache files in File array by getBaseContext().getCacheDir().listFiles() and then deletes one by one in a loop by file.delet() method

Kotlin has an one-liner

context.cacheDir.deleteRecursively()

Try this

@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
clearApplicationData();
}


public void clearApplicationData() {
File cache = getCacheDir();
File appDir = new File(cache.getParent());
if (appDir.exists()) {
String[] children = appDir.list();
for (String s : children) {
if (!s.equals("lib")) {
deleteDir(new File(appDir, s));
Log.i("EEEEEERRRRRROOOOOOORRRR", "**************** File /data/data/APP_PACKAGE/" + s + " DELETED *******************");
}
}
}
}


public static boolean deleteDir(File dir) {
if (dir != null && dir.isDirectory()) {
String[] children = dir.list();
int i = 0;
while (i < children.length) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
i++;
}
}


assert dir != null;
return dir.delete();
}

Put this code in onStop() method of MainActivity

@Override
protected void onStop() {
super.onStop();
AppUtils.deleteCache(getApplicationContext());
}
public class AppUtils {
public static void deleteCache(Context context) {
try {
File dir = context.getCacheDir();
deleteDir(dir);
} catch (Exception e) {}
}


public static boolean deleteDir(File dir) {
if (dir != null && dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
}
return dir.delete();
} else if(dir!= null && dir.isFile()) {
return dir.delete();
} else {
return false;
}
}
}

This code will remove your whole cache of the application, You can check on app setting and open the app info and check the size of cache. Once you will use this code your cache size will be 0KB . So it and enjoy the clean cache.

 if (Build.VERSION_CODES.KITKAT <= Build.VERSION.SDK_INT) {
((ActivityManager) context.getSystemService(ACTIVITY_SERVICE))
.clearApplicationUserData();
return;
}

If you're using kotlin, then:

context.cacheDir.deleteRecursively()

Using kotlin: to just remove the content:

for (file:File in context?.cacheDir?.listFiles()!!){
file.delete()
}

If you using Android Studio 4.4.2

getCacheDir().delete();

This code helped me:

// your code
deleteCache(getContext);
//


public void deleteCache(Context context) {
try {
File dir = context.getCacheDir();
if (dir.list() != null) {
deleteDir2(dir);
}
} catch (Exception e) { e.printStackTrace();}
}


public boolean deleteDir2(File dir) {
if (dir.isDirectory()) {
for (File child : dir.listFiles()) {
boolean success = deleteDir2(child);
if (!success) {
return false;
}
}
}
return dir.delete();
}