Question

在尝试更改视图Activity之后，我正尝试启动新的OnNavigationItemSelected。我可以正确地改变视图：

 if (fragment != null) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.content_frame, fragment);
        transaction.commit();
        setTitle(fragment.getArguments().getString("title"));
        drawer.setSelected(true);
        drawer.closeDrawer(GravityCompat.START);

        Intent intent = new Intent(MainActivity.this, GalleryActivity.class);
        startActivity(intent);

        return true;
}

有了这个，我想根据所选择的选项更改我想要显示内容的主视图。

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="es.antonio.miBoda.MainActivity"
    tools:showIn="@layout/app_bar_main">

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</android.support.constraint.ConstraintLayout>

fragment_gallery （我使用此视图更新主视图）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <TextView
        android:id="@+id/label"
        android:layout_alignParentTop="true"
        android:layout_marginTop="100dp"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:textSize="45dp"
        android:text="Connect"
        android:textStyle="bold"/>

    <TextView
        android:layout_below="@id/label"
        android:layout_centerInParent="true"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="12dp"
        android:layout_marginTop="10dp"
        android:gravity="center_horizontal"
        android:text="Edit fragment_connect.xml to change the appearance"
        android:id="@+id/textView2" />


    <android.support.design.widget.FloatingActionButton
        android:id="@+id/ic_take_picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_gravity="bottom|end"
        android:layout_marginBottom="18dp"
        android:layout_marginEnd="17dp"
        app:srcCompat="@android:drawable/ic_menu_camera" />

</RelativeLayout>

我可以完美地更新视图，但是当我开始新活动时，我无法获得浮动按钮ic_take_picture，它总是null。

我的 GalleryActivity

public class GalleryActivity extends Activity {

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

        FloatingActionButton takePicture = (FloatingActionButton) findViewById(R.id.ic_take_picture);
        if (null != takePicture) {
            takePicture.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            });
        }
    }
}

我可以获取按钮的唯一方法是setContentView(R.layout.fragment_gallery);但是如果我这样做，我的视图会发生变化，并且不像主视图。

那么，在视图替换之后如何启动新的Activity以使浮动按钮可用？

Answer 1

<强>解决

我已将此添加到我的片段中，而不是创建一个新的Activity：

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    FloatingActionButton takePicture = (FloatingActionButton) getView().findViewById(R.id.ic_take_picture);
    if (null != takePicture) {
        takePicture.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }
}

阅读Fragments它非常清楚。

新活动OnNavigationItemSelectedListener

1 个答案: