Question

我遇到了与片段生命周期有关的问题。

在此之前，我将设置DONT KEEP ACTIVITY模式（设置 - ＆gt;开发人员选项）。

在我的项目中有2项活动：

活动1：保留并控制片段A和片段B
活动2：没有片段。
1. 首先调用活动1，然后将片段A和片段B调用为可见。
2. 从活动1开始活动2，这导致活动1将被销毁，片段A＆amp;片段B也将被销毁（因为不保持活动模式）。
3. 按活动2中的返回键返回活动1

此处出现问题：从活动2返回后，片段A和片段B将自动调用onCreateView() - ＆gt;我想避免这种情况。你能给我一些解决方法吗？

更新代码

活动1

 public class MainActivity extends Activity implements OnClickListener {

    private Button mBtnShowFragmentA;

    private Button mBtnShowFragmentB;

    private Button mBtnGoAcitivity2;

    protected String mCurrentFragmentTag;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout_activity_1);
        mBtnShowFragmentA = (Button) findViewById(R.id.btn_show_fragmentA);
        mBtnShowFragmentB = (Button) findViewById(R.id.btn_show_fragmentB);
        mBtnGoAcitivity2 = (Button) findViewById(R.id.btn_go_activity2);
        mBtnShowFragmentA.setOnClickListener(this);
        mBtnShowFragmentB.setOnClickListener(this);
        mBtnGoAcitivity2.setOnClickListener(this);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    protected void addFragment(int contentId, Fragment fragment, boolean isAddStack,
            String stackName) {
        FragmentManager fm = getFragmentManager();
        String newFragment = fragment.getClass().getName();

        FragmentTransaction ft = fm.beginTransaction();

        Fragment currentFragment = fm.findFragmentByTag(mCurrentFragmentTag);

        if (currentFragment != null && !TextUtils.equals(currentFragment.getTag(), newFragment)) {
            ft.hide(currentFragment);
        }

        if (fm.findFragmentByTag(newFragment) != null) {
            fragment = (Fragment) fm.findFragmentByTag(newFragment);
        }

        if (!fragment.isAdded()) {
            ft.add(contentId, fragment, newFragment);
        } else {          
            ft.show(fragment);
        }

        if (isAddStack) {
            ft.addToBackStack(stackName);
        }
        try {
            ft.commitAllowingStateLoss();

        } catch (Exception e) {

        }
        mCurrentFragmentTag = newFragment;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_show_fragmentA:
                FragmentA fragmentA = new FragmentA();
                addFragment(R.id.activity_main_content, fragmentA, false, null);
                break;
            case R.id.btn_show_fragmentB:
                FragmentB fragmentB = new FragmentB();
                addFragment(R.id.activity_main_content, fragmentB, false, null);
                break;
            case R.id.btn_go_activity2:
                Intent intent = new Intent(getApplicationContext(), SettingActivity.class);
                startActivity(intent);

                break;
            default:
                break;
        }
    }
}

片段A

 public class FragmentA extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.layout_fragment_a, container, false);

        return view;
    }   
}

片段B

  public class FragmentB extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.layout_fragment_b, container, false);

        return view;
    }   
}

活动2

 public class SettingActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout_activity_2);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
    }
}

...................

Answer 1

使用以下代码从堆栈中删除活动。

FragmentManager fragmentManager = getSupportFragmentManager();

                if (fragmentManager .getBackStackEntryCount() > 0) {
                    fragmentManager .popBackStack();
                }

从Activity返回后重新创建片段

1 个答案: