Android：通过片段预览相机。好的活动

Question

我正在尝试使用片段显示相机预览，但它不显示预览，而是“捕获”按钮旁边的白色表情。

显示活动预览没有任何问题。这是我的代码：

来自活动：

MainActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Create an instance of Camera
    mCamera = getCameraInstance();

    // Create our Preview view and set it as the content of our activity.
    mPreview = new CameraPreview(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(mPreview);

}

activity_main.xml中

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
        <FrameLayout
            android:id="@+id/camera_preview"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1"
            />

        <Button
            android:id="@+id/button_capture"
            android:text="Capture"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            />
    </LinearLayout>

来自片段：

public class MainActivity extends AppCompatActivity


@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if (findViewById(R.id.fragment_container) != null) {

        ButtonFragment buttonFragment = new ButtonFragment();

        getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, buttonFragment).commit();
    }

fragment_button.xml

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
        <FrameLayout
            android:id="@+id/camera_preview"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1"
            />

        <Button
            android:id="@+id/button_capture"
            android:text="Capture"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            />
    </LinearLayout>

ButtonFragment.java

   public class ButtonFragment extends Fragment {

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

    // Create an instance of Camera
    mCamera = getCameraInstance();

    View rootView = inflater.inflate(R.layout.fragment_button, container, false);

    // Create our Preview view and set it as the content of our activity.
    mPreview = new CameraPreview(container.getContext(), mCamera);
    FrameLayout preview = (FrameLayout) rootView.findViewById(R.id.camera_preview);
    preview.addView(mPreview);

    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_button, container, false);
}

以下是调试时的值变量：

Answer 1

看起来问题是您在onCreateView()中重新充气布局，并返回那个布局，而不是附加了相机预览的布局。

返回rootView：

public class ButtonFragment extends Fragment {


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

      // Create an instance of Camera
      mCamera = getCameraInstance();

      View rootView = inflater.inflate(R.layout.fragment_button, container, false);

      // Create our Preview view and set it as the content of our activity.
      mPreview = new CameraPreview(container.getContext(), mCamera);
      FrameLayout preview = (FrameLayout) rootView.findViewById(R.id.camera_preview);
      preview.addView(mPreview);

      // Inflate the layout for this fragment
      //Don't inflate again and return:
      //return inflater.inflate(R.layout.fragment_button, container, false);

      //Instead, return the View with the camera preview:
      return rootView;
  }
 }