Question

我有fragment imagebutton和framelayout。创建片段时，它会将frameview添加到framelayout。这里是片段的xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageButton
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/watchButton"
        android:src="@drawable/wearc"
        android:scaleType="fitCenter"
        android:padding="0dp"
        android:onClick="onPic"
        android:contentDescription="@string/watch" />

    <FrameLayout
        android:id="@+id/camera_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="31.2dp">
    </FrameLayout>

</LinearLayout>

这里是我用于片段的java脚本：

package com.coralapps.face2face;

import android.app.Fragment;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.Toast;

public class CameraFragment extends Fragment {

    android.hardware.Camera mCamera;
    private CameraView mCameraView = null;

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

    public void setupCamera(View v){
        try{
            mCamera = Camera.open();//you can use open(int) to use different cameras
        } catch (Exception e){
            Log.d("ERROR", "Failed to get camera: " + e.getMessage());
        }

        if(mCamera != null) {
            mCameraView = new CameraView(getActivity(), mCamera);
            FrameLayout camera_view = (FrameLayout) v.findViewById(R.id.camera_view);
            camera_view.addView(mCameraView);
        }
    }
}

我得到的错误：

android.support.v7.widget.AppCompatImageButton cannot be cast to android.widget.FrameLayout at com.coralapps.face2face.CameraFragment.setupCamera(CameraFragment.java:41)

但是在第41行，我链接到R.id.camera_view，这显然是一个Framelayout，而不是一个Imagebutton。

我在这里做错了吗？

编辑：当我删除imagebutton时，这会有效。

Answer 1

private CameraView mCameraView = null;

通过初始化它就像你说它是CameraView，而不是FrameLayout。尝试用CameraView替换FrameLayout。如果它不像FrameLayout，LinearLayout等（在左侧列出），请尝试将其添加为自定义视图

Answer 2

兄弟，运行时代码没有错误！但我改变了这一行

   public void setupCamera(View v){
    try{
        mCamera = Camera.open();//you can use open(int) to use different cameras
    } catch (Exception e){
        Log.d("ERROR", "Failed to get camera: " + e.getMessage());
    }

    if(mCamera != null) {
        //change
       // mCameraView = new CameraView(getActivity(), mCamera);
        FrameLayout camera_view = (FrameLayout) v.findViewById(R.id.camera_view);
        camera_view.addView(mCameraView);
    }
}

Answer 3

我认为问题在于你在setupCamera(View v)中调用了onCreateView并作为参数传递了一个视图，但是不能保证它已经膨胀了。相反，您应该在创建视图后调用onResume()来捕获和操纵视图。所以你可以从setupCamera(v);方法拨打onResume()。

当我向其投射Framelayout时，无法将ImageButton强制转换为FrameLayout

3 个答案: