Introduction to Android AssetManager for reading Assets resources in Android development.

1 year ago
Liam
2 minutes

In Android development, the Assets folder is where non-code resources such as images, audio, and videos that an application needs to use are stored. These files in the Assets folder are kept in the APK file after the application is packaged and can be accessed and read using the AssetManager class.

The AssetManager is a class used for managing asset resources, providing a set of methods to read resource files in the Assets folder. To use the AssetManager class, you first need to obtain an AssetManager object through the getAssets() method of the Context.

AssetManager assetManager = context.getAssets();

Once you obtain the AssetManager object, you can use its methods to access resource files in the Assets folder. Common methods include:

  1. open(String fileName): Open the specified resource file by its file name and return an InputStream object, which can be used to read the file’s content.
  2. list(String path): Retrieves all file names in the specified path and returns a String array.
  3. openFd(String fileName): Open a specified resource file by its file name and return an AssetFileDescriptor object, which can be used to obtain information about the file.

Here is an example of reading a text file in the Assets folder.

AssetManager assetManager = context.getAssets();
try {
    InputStream inputStream = assetManager.open("text.txt");
    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
    String line;
    while ((line = reader.readLine()) != null) {
        // 处理每一行的内容
    }
    reader.close();
    inputStream.close();
} catch (IOException e) {
    e.printStackTrace();
}

The above code first opens a file named “text.txt” using the open() method of AssetManager, which returns an InputStream object. Then it uses BufferedReader and InputStreamReader to read the content of the file.

In conclusion, using AssetManager makes it easy to access files in the Assets folder, allowing for the reading of various types of files such as text, images, audio, and video.

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