Android编程入门-第93天

DragAndDrawActivity.java

import android.support.v4.app.Fragment;

public class DragAndDrawActivity extends SingleFragmentActivity {

    @Override
    protected Fragment createFragment() {
        return DragAndDrawFragment.newInstance();
    }
}

DragAndDrawFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class DragAndDrawFragment extends Fragment {

    public static DragAndDrawFragment newInstance() {
        return new DragAndDrawFragment();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_drag_and_draw, container, false);
        return v;
    }
}

SingleFragmentActivity.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;

public abstract class SingleFragmentActivity extends AppCompatActivity {

    protected abstract Fragment createFragment();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment);

        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.fragment_container);

        if (fragment == null) {
            fragment = createFragment();
            fm.beginTransaction()
                    .add(R.id.fragment_container, fragment)
                    .commit();
        }
    }
}