Android 滚动显示双重内容

Question

如果我在我的设置 activity 中滚动，内容会显示两次。在横向模式下似乎有一个新层可以滚动，而下面的层不会移动。

这是怎么回事？我没有在 class.

中添加太多代码

可能是我犯的一个愚蠢的错误。抱歉 - 我是 Android.

的新人

感谢您的回答。

public class AppPreferences extends AppCompatActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            android.app.FragmentManager fragmentManager = getFragmentManager();
            android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            SettingsFragment settingsFragment = new SettingsFragment();
            fragmentTransaction.add(android.R.id.content, settingsFragment, "SETTINGS_FRAGMENT");
            fragmentTransaction.commit();
        }

        public static class SettingsFragment extends PreferenceFragment {
            @Override
            public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                addPreferencesFromResource(R.xml.app_preferences);
            }
        }
    }

Answer 1

当您旋转设备时，框架正在创建片段，因此您不应创建它。

这样做：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (savedInstanceState == null) {
            android.app.FragmentManager fragmentManager = getFragmentManager();
            android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            SettingsFragment settingsFragment = new SettingsFragment();
            fragmentTransaction.add(android.R.id.content, settingsFragment, "SETTINGS_FRAGMENT");
            fragmentTransaction.commit();
        }
    }

Answer 2

改变

fragmentTransaction.add(android.R.id.content, settingsFragment, "SETTINGS_FRAGMENT");
            fragmentTransaction.commit();

到

fragmentTransaction.replace(android.R.id.content, settingsFragment, "SETTINGS_FRAGMENT");
            fragmentTransaction.commit();

也这样做：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (savedInstanceState == null) {
            android.app.FragmentManager fragmentManager = getFragmentManager();
            android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            SettingsFragment settingsFragment = new SettingsFragment();
            fragmentTransaction.add(android.R.id.content, settingsFragment, "SETTINGS_FRAGMENT");
            fragmentTransaction.commit();
        }
    }

按照@Francesc 的建议，它将保持您的片段状态，因此您不会丢失状态。

您添加的是片段而不是替换片段，这就是您看到片段两次的原因。

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