我希望在我自己的活动中显示前置或后置摄像头输入。另外，我希望用户控制两个摄像头的变焦。
我应该如何使用 Camera 对象调用，它不是已弃用吗？另外，如何让我的视图显示来自摄像机的实时数据？
【问题讨论】：
你应该试试the CameraKit library。 它易于使用并具有许多内置功能，例如：
【讨论】：
首先你需要检查设备是否支持使用多摄像头 那么你可以使用下面的代码 这是 MainActivity.class
import android.content.Context;
import android.hardware.Camera;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.FrameLayout;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create an instance of Camera
Camera mBackCamera = getCameraInstance(0);
// Create back camera Preview view and set it as the content of our activity.
BackCamera mBackCam = new BackCamera(this, mBackCamera);
FrameLayout backPreview = (FrameLayout) findViewById(R.id.back_camera_preview);
backPreview.addView(mBackCam);
Camera mFrontCamera = getCameraInstance(1);
FrontCamera mFrontCam = new FrontCamera(this, mFrontCamera);
FrameLayout frontPreview = (FrameLayout) findViewById(R.id.front_camera_preview);
frontPreview.addView(mFrontCam);
}
public static Camera getCameraInstance(int cameraId){
Camera c = null;
try {
c = Camera.open(cameraId); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
Log.e("TAG","Camera " + cameraId + " not available! " + e.toString() );
}
return c; // returns null if camera is unavailable
}
}
class FrontCamera extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public static String TAG = "FrontCamera";
public FrontCamera(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e) {
Log.d(TAG, "Error starting camera : " + e.getMessage());
}
}
}
class BackCamera extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public static String TAG = "BackCamera";
public BackCamera(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera : " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e) {
Log.d(TAG, "Error starting camera : " + e.getMessage());
}
}
}
这里是xml
<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"
tools:context="com.mooi.myapplication.MainActivity">
<FrameLayout
android:id="@+id/back_camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
/>
<FrameLayout
android:id="@+id/front_camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
/>
</android.support.constraint.ConstraintLayout>
【讨论】：