Android API之ExternalStorage操作

官方API文档：
https://developer.android.com/guide/topics/sensors/sensors_environment.html
https://developer.android.com/reference/android/os/Environment.html

/** * Android中外存储设备（SD卡）操作 *  * @description： * @author ldm * @date 2016-7-21 上午9:33:53 */public class ExternalStorage extends Activity {    // 装载控件的容器    private ViewGroup container;    /**     * Android的外部存储，在APILevel=8之前，所有的文件都是建议放在Environment.getExternalStorageState()目录下的。     * 从API Level=8开始，对于应用程序的私有文件应该放在Context.getExternalFilesDir目录下。     * 非私有的（shared）的文件应该放在目录下Environment.getExternalStoragePublicDirectory(String)所指定的目录下。     * 私有的文件放在Environment.getExternalStorageDirectory()所指定的目录下。     */    // 非私有图片    private Item mExternalStoragePublicPicture;    // 私有图片    private Item mExternalStoragePrivatePicture;    // 私有文件    private Item mExternalStoragePrivateFile;    // 处存储设备文件扫描广播    private BroadcastReceiver mExternalStorageReceiver;    // 外存储是否可用    boolean mExternalStorageAvailable = false;    // 外存储是否可写操作    boolean mExternalStorageWriteable = false;    // 自定义的Item    static class Item {        View mRoot;        // 创建文件的Button        Button mCreate;        // 删除文件Button        Button mDelete;    }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.external_storage);        initViews();        addViewsToContainer();        startWatchingExternalStorage();    }    /**     * 给ViewGroup添加View     *      * @description：     * @author ldm     * @date 2016-7-21 上午9:06:33     */    private void addViewsToContainer() {        mExternalStoragePublicPicture = createStorageControls(                "Picture: getExternalStoragePublicDirectory",                Environment                        .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),                new View.OnClickListener() {                    public void onClick(View v) {                        createExternalStoragePublicPicture();                        updateExternalStorageState();                    }                }, new View.OnClickListener() {                    public void onClick(View v) {                        deleteExternalStoragePublicPicture();                        updateExternalStorageState();                    }                });        container.addView(mExternalStoragePublicPicture.mRoot);        mExternalStoragePrivatePicture = createStorageControls(                "Picture getExternalFilesDir",                getExternalFilesDir(Environment.DIRECTORY_PICTURES),                new View.OnClickListener() {                    public void onClick(View v) {                        createExternalStoragePrivatePicture();                        updateExternalStorageState();                    }                }, new View.OnClickListener() {                    public void onClick(View v) {                        deleteExternalStoragePrivatePicture();                        updateExternalStorageState();                    }                });        container.addView(mExternalStoragePrivatePicture.mRoot);        mExternalStoragePrivateFile = createStorageControls(                "File getExternalFilesDir", getExternalFilesDir(null),                new View.OnClickListener() {                    public void onClick(View v) {                        createExternalStoragePrivateFile();                        updateExternalStorageState();                    }                }, new View.OnClickListener() {                    public void onClick(View v) {                        deleteExternalStoragePrivateFile();                        updateExternalStorageState();                    }                });        container.addView(mExternalStoragePrivateFile.mRoot);    }    private void initViews() {        container = (ViewGroup) findViewById(R.id.container);    }    @Override    protected void onDestroy() {        super.onDestroy();        stopWatchingExternalStorage();    }    private void handleExternalStorageState(boolean available, boolean writeable) {        boolean has = hasExternalStoragePublicPicture();        mExternalStoragePublicPicture.mCreate.setEnabled(writeable && !has);        mExternalStoragePublicPicture.mDelete.setEnabled(writeable && has);        has = hasExternalStoragePrivatePicture();        mExternalStoragePrivatePicture.mCreate.setEnabled(writeable && !has);        mExternalStoragePrivatePicture.mDelete.setEnabled(writeable && has);        has = hasExternalStoragePrivateFile();        mExternalStoragePrivateFile.mCreate.setEnabled(writeable && !has);        mExternalStoragePrivateFile.mDelete.setEnabled(writeable && has);    }    private void updateExternalStorageState() {        String state = Environment.getExternalStorageState();        if (Environment.MEDIA_MOUNTED.equals(state)) {            mExternalStorageAvailable = mExternalStorageWriteable = true;        } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {            mExternalStorageAvailable = true;            mExternalStorageWriteable = false;        } else {            mExternalStorageAvailable = mExternalStorageWriteable = false;        }        handleExternalStorageState(mExternalStorageAvailable,                mExternalStorageWriteable);    }    private void startWatchingExternalStorage() {        mExternalStorageReceiver = new BroadcastReceiver() {            @Override            public void onReceive(Context context, Intent intent) {                updateExternalStorageState();            }        };        IntentFilter filter = new IntentFilter();        filter.addAction(Intent.ACTION_MEDIA_MOUNTED);        filter.addAction(Intent.ACTION_MEDIA_REMOVED);        registerReceiver(mExternalStorageReceiver, filter);        updateExternalStorageState();    }    private void stopWatchingExternalStorage() {        unregisterReceiver(mExternalStorageReceiver);    }    // 创建外存储中公共图片    private void createExternalStoragePublicPicture() {        File path = Environment                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);        File file = new File(path, "DemoPicture.jpg");        try {            path.mkdirs();            InputStream is = getResources()                    .openRawResource(R.drawable.balloons);            OutputStream os = new FileOutputStream(file);            byte[] data = new byte[is.available()];            is.read(data);            os.write(data);            is.close();            os.close();            // 媒体文件进行扫描，看是否有新文件，使得MediaProvider同步媒体数据库            // scanFile(Context context, String[] paths, String[] mimeTypes,            // OnScanCompletedListener callback)            // 传入参数分别是上下文对象,文件路径对应的数组，文件类型及扫描监听            MediaScannerConnection.scanFile(this,                    new String[] { file.toString() }, null,                    new MediaScannerConnection.OnScanCompletedListener() {                        public void onScanCompleted(String path, Uri uri) {                            Log.i("ExternalStorage", "Scanned " + path + ":");                            Log.i("ExternalStorage", "-> uri=" + uri);                        }                    });        } catch (IOException e) {            e.printStackTrace();        }    }    // 删除外存储中是否有指定的公共图片    private void deleteExternalStoragePublicPicture() {        File path = Environment                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);        File file = new File(path, "DemoPicture.jpg");        file.delete();    }    // 判断外存储中是否有指定的公共图片    private boolean hasExternalStoragePublicPicture() {        File path = Environment                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);        File file = new File(path, "DemoPicture.jpg");        return file.exists();    }    // 在外存储中创建私有文件    private void createExternalStoragePrivatePicture() {        // 创建文件        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);        File file = new File(path, "DemoPicture.jpg");        try {            InputStream is = getResources()                    .openRawResource(R.drawable.balloons);            OutputStream os = new FileOutputStream(file);            byte[] data = new byte[is.available()];            is.read(data);            os.write(data);            is.close();            os.close();            // 媒体文件进行扫描，看是否有新文件，使得MediaProvider同步媒体数据库            // scanFile(Context context, String[] paths, String[] mimeTypes,            // OnScanCompletedListener callback)            // 传入参数分别是上下文对象,文件路径对应的数组，文件类型及扫描监听            MediaScannerConnection.scanFile(this,                    new String[] { file.toString() }, null,                    new MediaScannerConnection.OnScanCompletedListener() {                        public void onScanCompleted(String path, Uri uri) {                            // 扫描完成后处理                        }                    });        } catch (IOException e) {            e.printStackTrace();        }    }    // 删除外存储中指定的私有图片    private void deleteExternalStoragePrivatePicture() {        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);        if (path != null) {            File file = new File(path, "DemoPicture.jpg");            file.delete();        }    }    // 判断是否有指定的图片    private boolean hasExternalStoragePrivatePicture() {        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);        if (path != null) {            File file = new File(path, "DemoPicture.jpg");            return file.exists();        }        return false;    }    //在外存储中创建私有文件    private void createExternalStoragePrivateFile() {        File file = new File(getExternalFilesDir(null), "DemoFile.jpg");        try {            InputStream is = getResources()                    .openRawResource(R.drawable.balloons);            OutputStream os = new FileOutputStream(file);            byte[] data = new byte[is.available()];            is.read(data);            os.write(data);            is.close();            os.close();        } catch (IOException e) {            e.printStackTrace();        }    }    private void deleteExternalStoragePrivateFile() {        // 获取外部存储文件的路径。如果文件存在则删除        File file = new File(getExternalFilesDir(null), "DemoFile.jpg");        if (file != null) {            file.delete();        }    }    private boolean hasExternalStoragePrivateFile() {        // 获取外部存储文件的路径。如果文件不存在，则返lse        File file = new File(getExternalFilesDir(null), "DemoFile.jpg");        return (file != null) && file.exists();    }    /**     *      * @description：创建Item对View     * @author ldm     * @date 2016-7-21 上午9:08:00     */    private Item createStorageControls(CharSequence label, File path,            View.OnClickListener createClick, View.OnClickListener deleteClick) {        // 获取系统LayoutInflater        LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);        // 始化Item        Item item = new Item();        item.mRoot = inflater.inflate(R.layout.external_storage_item, null);        TextView tv = (TextView) item.mRoot.findViewById(R.id.label);        tv.setText(label);        if (path != null) {            tv = (TextView) item.mRoot.findViewById(R.id.path);            tv.setText(path.toString());        }        // 初始化Button及点击事件        item.mCreate = (Button) item.mRoot.findViewById(R.id.create);        item.mCreate.setOnClickListener(createClick);        item.mDelete = (Button) item.mRoot.findViewById(R.id.delete);        item.mDelete.setOnClickListener(deleteClick);        return item;    }}

—-布局文件——

<?xml version="1.0" encoding="utf-8"?><ScrollView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:scrollbars="none" >    <LinearLayout        android:id="@+id/container"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical" >    </LinearLayout></ScrollView>