如何在android中保存文本视图?

帮助我找到解决方案。下面是我在文本视图中扫描和显示的代码,现在我想以任意格式保存此文本视图。

下面是我的代码。

public class MainActivity extends AppCompatActivity {
TextView tv;
Button bt;
String contents="", format="";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tv = (TextView)findViewById(R.id.contents);
    bt = (Button)findViewById(R.id.save);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent in) {
    IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, in);
    if (scanningResult != null) {
        try {
            contents = in.getStringExtra("SCAN_RESULT");
            format = in.getStringExtra("SCAN_RESULT_FORMAT");
            tv.setText("Content-" + contents + "\n" + " Format-" + format);
        }
        catch (NullPointerException e){}
    }
}

public void save(View v){
    if(contents.equals("")){
        Toast.makeText(getApplication(),"Click Camera icon to Scan BarCode",Toast.LENGTH_LONG).show();
    }
    else{
        //search scan result on web
        startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(contents)));
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);//Menu Resource, Menu
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.action_camera:
            IntentIntegrator scanIntegrator = new IntentIntegrator(MainActivity.this);
            scanIntegrator.initiateScan();
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}
}

如何使用共享首选项实现这一点?