import java.io.File;import android.os.Build;import android.os.Bundle;import android.os.Environment;import android.os.StatFs;import android.app.Activity;import android.text.format.Formatter;import android.view.Menu;import android.widget.TextView;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                 File path = Environment.getExternalStorageDirectory();         StatFs stat = new StatFs(path.getPath());         long blockSize;         long totalBlocks;         long availableBlocks;                           //检测系统当前版本号         if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2){            blockSize = stat.getBlockSizeLong();            totalBlocks = stat.getBlockCountLong();            availableBlocks = stat.getAvailableBlocksLong();         }         else{            blockSize = stat.getBlockSize();            totalBlocks = stat.getBlockCount();            availableBlocks = stat.getAvailableBlocks();         }                  TextView tv = (TextView) findViewById(R.id.tv);         tv.setText(formatSize(availableBlocks * blockSize));    }     private String formatSize(long size) {            return Formatter.formatFileSize(this, size);       }}