public abstract File getCacheDir ()
Returns the absolute path to the application specific cache directory on
the filesystem. These files will be ones that get deleted first when
the device runs low on storage. There is no guarantee when these files
will be deleted. Note: you should not rely on
the system deleting these files for you; you should always have a
reasonable maximum, such as 1 MB, for the amount of space you consume
with cache files, and prune those files when exceeding that space.
存储空间剩余多少的情况，没有严格的标准保障。
注意：你不应该依赖系统来清理这些缓存文件，你应该对这些缓存文件占用的最大存储空间设定个最大值，比如是1M，当实际占用空间超过这个值时，你应该对这些缓存文件做相应的清理工作（prune）。
Returns
- Returns the path of the directory holding application cache files.
See Also
openFileOutput(String,
int)getFileStreamPath(String)getDir(String,
int)- import android.app.Activity;
- import android.content.Context;
- import android.os.Bundle;
- import android.util.Log;
- public class MainActivity extends Activity {
- final static String TAG="robin";
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- Context context=this;
- String path=context.getCacheDir().getAbsolutePath();
- Log.i(TAG,"path:"+path);
- }
- }
- path:/data/data/com.lenovo/cache
public abstract File getDir (String name,
int mode)
Retrieve, creating if needed, a new directory in which the application
can place its own custom data files. You can use the returned File
object to create and access files in this directory. Note that files
created through a File object will only be accessible
by your own application; you can only set the mode of the entire
directory, not of individual files.
：参数是指文件夹的访问权限而并不包括其子文件夹和文件的访问权限
Parameters
name
| Name of the directory to retrieve. This is a directory that is created as part of your application data. | |
| mode |
Operating mode. Use 0 or MODE_PRIVATE forthe default operation, MODE_WORLD_READABLE and MODE_WORLD_WRITEABLE tocontrol permissions. |
|---|
Returns
- Returns a File object for the requested directory. The directory will have been created if it does not already exist.
See Also
openFileOutput(String,
int)- File file=context.getDir("download", Context.MODE_PRIVATE);
- String path=file.getAbsolutePath();
- Log.i(TAG,"path:"+path);
-
public abstract File getFileStreamPath (String name)
Since: API Level 1Returns the absolute path on the filesystem where a file created with
openFileOutput(String,is stored.
int)Parameters
name
The name of the file for which you would like to get its path. Returns
- Returns an absolute path to the given file.
See Also
openFileOutput(String,
int)getFilesDir()getDir(String,
int)- File file=context.getFileStreamPath("download");
- String path=file.getAbsolutePath();
- Log.i(TAG,"path:"+path);
-
public abstract File getFilesDir ()
Since: API Level 1Returns the absolute path to the directory on the filesystem where files created with
openFileOutput(String,are stored.
int)Returns
- Returns the path of the directory holding application files.
示例4File file=context.getFilesDir();String path=file.getAbsolutePath();Log.i(TAG,"path:"+path);运行结果10-02 09:15:11.102: I/robin(12359): path:/data/data/com.lenovo/filespublic abstract FileInputStream openFileInput (String name)
Since: API Level 1Open a private file associated with this Context's application package for reading.
Parameters
name The name of the file to open; can not contain path separators. Returns
- FileInputStream Resulting input stream.
Throws
FileNotFoundException public abstract FileOutputStream openFileOutput (String name, int mode)
Since: API Level 1Open a private file associated with this Context's application package for writing. Creates the file if it doesn't already exist.
Parameters
name The name of the file to open; can not contain path separators. mode Operating mode. Use 0 or MODE_PRIVATEfor the default operation,MODE_APPENDto append to an existing file,MODE_WORLD_READABLEandMODE_WORLD_WRITEABLEto control permissions.Returns
- FileOutputStream Resulting output stream.
Throws
FileNotFoundException See Also
示例5
public abstract boolean deleteFile (String name)
Delete the given private file associated with this Context's application package.
Parameters
name
| The name of the file to delete; can not contain path separators. |
Returns
- True if the file was successfully deleted; else false.
public abstract String[] fileList ()
Returns an array of strings naming the private files associated with this Context's application package.
Returns
- Array of strings naming the private files.
Gets the Android data directory.
用File返回数据文件的根目录，返回的文件的路径为“/data”。该目录下的文件是只读。应用程序无法对该目录下的文件进行写操作。
Gets the android Download/Cache content directory.
用File返回缓存文件的根目录，返回的文件的路径为“/cache”。对于第三方应用程序。该目录下的文件是只读。第三方应用程序无法对该目录下的文件进行写操作。
public static File getRootDirectory ()
用File返回Android系统文件的根目录，返回的文件的路径为“/system”。该目录下的文件是只读。应用程序无法对该目录下的文件进行写操作。