Android API之ExternalStorage操作

/**
* 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;
}
}

<?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>