android 2.2 apidemos 赏析笔记 6 -

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android 2.2 apidemos 赏析笔记 6

ReadAsset.JAVA
SEE:
try {
 InputStream is = getAssets().open("read_asset.txt");
 int size = is.available();
 byte[] buffer = new byte[size];
 is.read(buffer);
 is.close();
 String text = new String(buffer);
 } catch (IOException e) {
 // Should never happen!
 throw new RuntimeException(e);
 }
SO:
仿照着写吧

ResourcesSample.java

SEE:
 <string name="styled_text">Plain, bold, italic, bold-italic</string>
1.
 CharSequence cs;
 tv.setText(cs);
2.
 String str;
 tv.setText(str);
3.
 Resources res = context.getResources();
 cs = res.getText(R.string.styled_text);
SO:
1.
设置TextView带格式
2.
string设置不带格式
3.
在某些地方可以这么获得字符串

StyledText.java

写在layout里的也可以显示格式

ExternalStorage.java

SEE:
1.
 ViewGroup mLayout;
 mLayout = (ViewGroup)findViewById(R.id.layout);
2.
 LayoutInflater inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
 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());
 }
 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;
3.
 mLayout.addView(mExternalStoragePublicPicture.mRoot);
SO:
1.各种layout通用的ViewGroup，如果只是往里面加东西的话
2.创建布局的过程。View.findViewById()
3.添加view

SEE:
1.
 void startWatchingExternalStorage() {
 mExternalStorageReceiver = new BroadcastReceiver() {
 @Override
 public void onReceive(Context context, Intent intent) {
 Log.i("test", "Storage: " + intent.getData());
 updateExternalStorageState();
 }
 };
 IntentFilter filter = new IntentFilter();
 filter.addAction(Intent.ACTION_MEDIA_MOUNTED);
 filter.addAction(Intent.ACTION_MEDIA_REMOVED);
 registerReceiver(mExternalStorageReceiver, filter);
 updateExternalStorageState();
 }
2.
 void stopWatchingExternalStorage() {
 unregisterReceiver(mExternalStorageReceiver);
 }

SO:
1.broadcastReceiver注册
2.取消注册
3.

SEE:
1.
 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);
2.
 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);
 }

SO:
1.存取状态获取
2.更新组件状态。

SEE:
1.
 boolean hasExternalStoragePublicPicture() {
 // Create a path where we will place our picture in the user's
 // public pictures directory and check if the file exists. If
 // external storage is not currently mounted this will think the
 // picture doesn't exist.
 File path = Environment.getExternalStoragePublicDirectory(
 Environment.DIRECTORY_PICTURES);
 File file = new File(path, "DemoPicture.jpg");
 return file.exists();
 }
2.
 boolean hasExternalStoragePrivatePicture() {
 // Create a path where we will place our picture in the user's
 // public pictures directory and check if the file exists. If
 // external storage is not currently mounted this will think the
 // picture doesn't exist.
 File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
 if (path != null) {
 File file = new File(path, "DemoPicture.jpg");
 return file.exists();
 }
 return false;
 }
3.
 boolean hasExternalStoragePrivateFile() {
 // Get path for the file on external storage. If external
 // storage is not currently mounted this will fail.
 File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
 if (file != null) {
 return file.exists();
 }
 return false;
 }

SO:
1.公共的图片文件夹 Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES) sdcard/picture
2.程序私有的文件夹目录下的图片文件夹 getExternalFilesDir(Environment.DIRECTORY_PICTURES) sdcard/android/data/pacagename/file/picture
3.程序私有的文件夹 getExternalFilesDir(null) sdcard/android/data/pacagename/file
4.都靠 file.exists()。。。

SEE:
1.
 File path = Environment.getExternalStoragePublicDirectory(
 Environment.DIRECTORY_PICTURES);
 File file = new File(path, "DemoPicture.jpg");
 path.mkdirs();
2.
 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();
3.
 // Tell the media scanner about the new file so that it is
 // immediately available to the user.
 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);
 }
 });
4.
 File path = Environment.getExternalStoragePublicDirectory(
 Environment.DIRECTORY_PICTURES);
 File file = new File(path, "DemoPicture.jpg");
 file.delete();
5.
 File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
 if (file != null) {
 file.delete();
 }
SO:
1.
获得路径，并创建。
2.
图片资源读取
文件的读写。
3.
通知多媒体扫描收集器。
4.
文件删除工作。
5.
文件夹删除。

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