Android : Store and use files in Assets

 There are times when you probably want to your application distribution with raw resources, instead of pre-defined resources, the ‘res‘ folder, you gonna have to make use of ‘Asset‘.

‘Assets’ folder will be distributed along with the APK, which contains all the raw files you need for application, such as: text files (.txt), non-Android XML files (.xml), Audio files (.wav, .mp3, .mid)…; those cannot be put into ‘res‘ folder as usual.

Thing needed to be looked up here: AssetManager from Android Developers’ References

This class does the job that we need.

First, create a project as usual, then put files into ‘asset‘ like below:

Now, create a simple layout containing a TextView for displaying the content of ‘text.txt‘ and an ImageView for displaying the image ‘avatar.jpg’, which are put in Asset.

The implementation quite easy using AssetManager as mentioned above.

package lapet.android.learn;
 
import java.io.IOException;
import java.io.InputStream;
 
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
 
public class Main extends Activity {
 
    ImageView mImage;
    TextView mText;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
 
        mImage = (ImageView)findViewById(R.id.image);
        mText = (TextView)findViewById(R.id.text);
        loadDataFromAsset();
    }
 
    public void loadDataFromAsset() {
        // load text
        try {
            // get input stream for text
            InputStream is = getAssets().open("text.txt");
            // check size
            int size = is.available();
            // create buffer for IO
            byte[] buffer = new byte[size];
            // get data to buffer
            is.read(buffer);
            // close stream
            is.close();
            // set result to TextView
            mText.setText(new String(buffer));
        }
        catch (IOException ex) {
            return;
        }
 
        // load image
        try {
            // get input stream
            InputStream ims = getAssets().open("avatar.jpg");
            // load image as Drawable
            Drawable d = Drawable.createFromStream(ims, null);
            // set image to ImageView
            mImage.setImageDrawable(d);
        }
        catch(IOException ex) {
            return;
        }
 
    }
}

That’s a quick sample code giving this result.