android - 如何按字符串名称打开 fragment ？

Question

我想打开一个随机 fragment 。现在我打开它生成一个随机数并使用开关、案例 1、案例 2 等，我打开 fragment 1、2 等。这些 fragment 是级别，它们的名称是:Nivel1、Nivel2 等。

但是我想做100多个关卡，如果用这种方法代码量会很大。有什么方法可以生成随机数，然后如果数字是 2 则显示 Nivel2() fragment 等？

这是我的实际代码:

public class Xtreme extends Activity {
String SiguienteNivel;
static int randomFragmentNum;
static int NivelesTotales=30;
static Random random = new Random();
FragmentManager fragmentManager = getFragmentManager();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_xtreme);
    randomFragmentNum = random.nextInt(7);
    Fragment();
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

public void Fragment() {
    switch (randomFragmentNum) {
        case 0: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel1()).commit();
            break;
        }
        case 1: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel2()).commit();
            break;
        }
        case 2: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel3()).commit();
            break;
        }
        case 3: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel4()).commit();
            break;
        }
        case 4: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel5()).commit();
            break;
        }
        case 5: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel6()).commit();
            break;
        }
        case 6: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel7()).commit();
            break;
        }
        case 7: {
            fragmentManager.beginTransaction().replace(R.id.container, new Nivel8()).commit();
            break;
        }
    }
}
}

Answer 1

您可以通过名称创建一个类:

try{
    Fragment f = (Fragment)(Class.forName("com.example.Fragment"+i).newInstance());
    fragmentManager.beginTransaction().replace(R.id.container,f).commit();
}catch(ClassNotFoundException e){
    Log.e("loading level","level class not found",e);
}