如何清除缓存Android

Question

I need to find a way how to clear the data which my application stores in cache.Basically I am using Fedor's ( Lazy load of images in ListView ) lazy list implementation and I want to clear the cache automatically when I have for example 100 images loaded.Any ideas how to do that?

EDIT: Code :

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    list=(ListView)findViewById(R.id.list);
    adapter=new LazyAdapter(this, mStrings);
    list.setAdapter(adapter);

    deleteCache(this);
    adapter.notifyDataSetChanged();


}

public static void deleteCache(Context context) {
    try {
        File dir = context.getCacheDir();
        if (dir != null && dir.isDirectory()) {
            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();
}

Answer 1

this will delete cache

public static void deleteCache(Context context) {
    try {
        File dir = context.getCacheDir();
        if (dir != null && dir.isDirectory()) {
            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();
}

Answer 2

I hope this helps you in getting further

public static void trimCache(Context context) {
    File dir = context.getCacheDir();
    if(dir!= null && dir.isDirectory()){
        File[] children = dir.listFiles();
        if (children == null) {
            // Either dir does not exist or is not a directory
        } else {
            File temp;
            for (int i = 0; i < children.length; i++) {
                temp = children[i];
                temp.delete();
            }
        }

    }

} 

Answer 3

you can call system service clearApplicationUserData() ( working only for >= KitKat version )

so you can do a check for version and then everything will go fine :) here is the code :

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            ((ActivityManager) getActivity().getSystemService(Context.ACTIVITY_SERVICE))
                    .clearApplicationUserData();
    }

Answer 4

If using Apache Commons IO, you can accomplish this with a single line (excluding try-catch):

try {
    FileUtils.deleteDirectory(context.getCacheDir());
} catch (IOException e) {
    // Do some error handling
}

Answer 5

With Kotlin you can just call

File(context.cacheDir.path).deleteRecursively()

Same result as the other answers, but no need for the checks and looping through manually

Answer 6

Discard old adapter and attach the listview to a new instance of the adapter (listview will lose scroll position, though). Example:

    @Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    m_adapter = new MyAdapter(this);
        final ListView listView = (ListView) getView()
                .findViewById(R.id.my_list);
        listView.setAdapter(m_adapter);
    }
}