如何为前置摄像头添加切换按钮

Question

需要帮助添加按钮或ImageView以便切换到前置摄像头，请帮忙！！！有人能帮我吗？我一直在尝试添加它，但我在切换相机时一直出错。我试图实现一个与前置摄像头分离的意图，但当切换回后置摄像头时，屏幕将保持黑色。我想以正确的方式安装前置摄像头，如果有人能帮忙的话，谢谢。如果你能，请将前置摄像头的源代码添加到我的项目中，如果你能的话，谢谢。

ImageView cameraFront;
private int width, height;
private int sdkVersion;
private int timeCount = 0;
private int PORTRAIT = 0;
private int PORTRAIT_REV = 1;
private int LANDSCAPE_RIGHT = 2;
private int LANDSCAPE_LEFT = 3;
private SurfaceView surface;
private SurfaceHolder surfaceHolder;
private MediaRecorder videoRecorder;
private Button recordBtn;
private TextView timeView;
private String videoPath;
private Timer autoStopTimer;
private Camera mCamera;
private Camera.Parameters parameters;
private List<Size> supportedSizes = null;
private SensorManager sensorManager = null;
private boolean isRecording = false;
boolean changeOrientation = false;
int mDetected_Orientention = 0;
Tosty toast;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    try {
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_GAME);
        setContentView(R.layout.video_recorder);
        videoPath = getIntent().getStringExtra("videoPath");
        width = getIntent().getIntExtra("Width", 320);
        height = getIntent().getIntExtra("Height", 240);
        WindowManager mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
        Display mDisplay = mWindowManager.getDefaultDisplay();
        this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        toast = new Tosty(VideoRecorder.this);
        recordBtn = (Button) findViewById(R.id.recordBtn);
        recordBtn.setOnClickListener(this);
        surface = (SurfaceView) findViewById(R.id.surfaceView);
        surfaceHolder = surface.getHolder();
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        timeView = (TextView) findViewById(R.id.timeView);
        timeView.setTextColor(Color.WHITE);
        initVideoRecording();
        initView();
        setListener();
    }
    catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
}
public void initView() {
    cameraFront = (ImageView) findViewById(R.id.cameraSwitch1);
}
public void setListener() {
    cameraFront.setOnClickListener(this);
}

@Override
protected void onResume() {
    super.onResume();
    (new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                Thread.sleep(100);
            } 
            catch (InterruptedException e) {
                e.printStackTrace();
            }
            try {
                initVideoRecording();
                //finish();
            } 
            catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    })).start();
}
@Override
public void onDestroy() {
    super.onDestroy();
    // Stop sensorManager
    sensorManager.unregisterListener(VideoRecorder.this);
    if (autoStopTimer != null) {
        autoStopTimer.cancel();
        autoStopTimer.purge();
        autoStopTimer = null;
    }
    try {
        stopVideoRecording();
    } 
    catch (Exception e) {
        // TODO Auto-generated catch block
    }
}
@Override
public void onPause() {
    super.onPause();
    if (autoStopTimer != null) {
        autoStopTimer.cancel();
        autoStopTimer.purge();
        autoStopTimer = null;
    }
    try {
        stopVideoRecording();
    } 
    catch (Exception e) {
        // TODO Auto-generated catch block
    }
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        // toast.showToast("Back button is pressed");
        sensorManager.unregisterListener(VideoRecorder.this);
        finish();
        return true;
    } 
    else if (keyCode == KeyEvent.KEYCODE_HOME) {
        try {
            stopVideoRecording();
        }
        catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    return super.onKeyDown(keyCode, event);
}
public void onBackPressed() {
    startActivity(new Intent(this, VideoPlay.class)
    .setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK));
    //overridePendingTransition(R.anim.left_right, R.anim.right_left);
    finish();
    return;
}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    switch (v.getId()) {
    case R.id.cameraSwitch1:

        Intent intent = new Intent(VideoRecorder.this, Cemara.class);
        //intent.putExtra("android.intent.extras.CAMERA_FACING", 1);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
        //intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
        finish();
        startActivity(intent);
        break;
    }
    if (v == recordBtn) {
        try {
            if (isRecording) {
            if (autoStopTimer != null) {
                autoStopTimer.cancel();
                autoStopTimer.purge();
                autoStopTimer = null;
            }
            try {
                stopVideoRecording();
            }
            catch (Exception e) {
                // TODO Auto-generated catch block
            }
            setResult(RESULT_OK);
            finish();
            } 
            else {
                startVideoRecording();
                autoStopTimer = new Timer();        
                autoStopTimer.schedule(new TimerTask() {
                public void run() {
                    timeCount++;
                    runOnUiThread(new Runnable() {
                        public void run() {
                            timeView.setText(String.format("00:%02d", timeCount));
                            if (timeCount == 31) {
                                try {
                                    stopVideoRecording();
                                } 
                                catch (Exception e) {
                                    // TODO Auto-generated catch block
                                }
                                setResult(RESULT_OK);
                                finish();
                            }
                        }
                    });
                    if (timeCount == 31) {
                        autoStopTimer.cancel();
                        autoStopTimer = null;
                    }
                }
                }, 1000, 1000);
            }
        }
        catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
        }
    }
}
private void initVideoRecording() {
    try {
        if (videoRecorder != null) {
            videoRecorder.stop();
            videoRecorder.release();
            videoRecorder = null;
        }
        if (mCamera != null) {
            mCamera.reconnect();
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        }
        sdkVersion = Build.VERSION.SDK_INT;
        android.hardware.Camera.CameraInfo info = new android.hardware.Camera.CameraInfo();
        android.hardware.Camera.getCameraInfo(0, info);
        mCamera = Camera.open();
        //parameters.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
        //parameters.set("focus-mode", "continuous-video");
        //mCamera.setParameters(parameters);
        // Camera setup is based on the API Camera Preview demo
        mCamera.setPreviewDisplay(surfaceHolder);
        parameters = mCamera.getParameters();
        if (sdkVersion <= 8) {
            supportedSizes = parameters.getSupportedVideoSizes();
        }
        // parameters.setRotation(90);
        mCamera.setParameters(parameters);
        // check the intial orientation depending on rotation
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        int nCurrentOrientation = _getScreenOrientation();
        if (nCurrentOrientation == Configuration.ORIENTATION_PORTRAIT && rotation == Surface.ROTATION_0) {
            System.out.println("We are in portrait mode");
            // parameters.setRotation(0);
            mCamera.setDisplayOrientation(90);
        } 
        else if (nCurrentOrientation == Configuration.ORIENTATION_LANDSCAPE && rotation == Surface.ROTATION_90) {
            System.out.println("We are in landscape mode");
            // parameters.setRotation(0);
            mCamera.setDisplayOrientation(0);
        } 
        else if (nCurrentOrientation == Configuration.ORIENTATION_LANDSCAPE && rotation == Surface.ROTATION_270) {
            System.out.println("Reverse Landscape Mode");
            mCamera.setDisplayOrientation(180);
        } 
        else if (nCurrentOrientation == Configuration.ORIENTATION_PORTRAIT && rotation == Surface.ROTATION_180) {
            System.out.println("Reverse potrait mode");
            mCamera.setDisplayOrientation(90);
        }
        else
            mCamera.setDisplayOrientation(90);
        mCamera.startPreview();
        mCamera.unlock();
    } 
    catch (Exception e) {
        e.printStackTrace();
    }
}
private void stopVideoRecording() throws Exception {
    try {
    if (videoRecorder != null) {
        videoRecorder.stop();
        videoRecorder.release();
        videoRecorder = null;
    }
    if (mCamera != null) {
        mCamera.reconnect();
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }
}
    catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
}
private void startVideoRecording() {
    try {
    if (videoRecorder == null) {
        videoRecorder = new MediaRecorder();
    }
    videoRecorder.setCamera(mCamera);
    videoRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    videoRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    videoRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    videoRecorder.setAudioEncodingBitRate(128000);
    videoRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
    videoRecorder.setAudioChannels(1);
    videoRecorder.setAudioSamplingRate(48000);
    if (width == 1280) {
        videoRecorder.setVideoEncodingBitRate(22100000);
    } 
    else if (width == 720) {
        videoRecorder.setVideoEncodingBitRate(3508000);
    } 
    else {
        videoRecorder.setVideoEncodingBitRate(777000);
    }
    videoRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
    videoRecorder.setVideoFrameRate(30);
    videoRecorder.setVideoSize(width, height);
    videoRecorder.setPreviewDisplay(surfaceHolder.getSurface());
    videoRecorder.setOrientationHint(90);
    if (mDetected_Orientention == PORTRAIT) {
        videoRecorder.setOrientationHint(90);
    } 
    else if (mDetected_Orientention == PORTRAIT_REV) {
        videoRecorder.setOrientationHint(270);
    } 
    else if (mDetected_Orientention == LANDSCAPE_RIGHT) {
        videoRecorder.setOrientationHint(180);
    }
    try {
        videoRecorder.setOutputFile(videoPath);
        videoRecorder.prepare();
        videoRecorder.start();
        isRecording = true;
        recordBtn.setText("STOP");
    } 
    catch (Exception e) {
        Log.e("Video", "Failed to prepare and start video recording", e);
        videoRecorder.release();
        videoRecorder = null;
    }
    }
    catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    try {
    int rotation = getWindowManager().getDefaultDisplay().getRotation();
    int nCurrentOrientation = _getScreenOrientation();
    if (nCurrentOrientation == Configuration.ORIENTATION_PORTRAIT && rotation == Surface.ROTATION_0) {
        System.out.println("We are in portriat mode");
        // parameters.setRotation(0);
        mCamera.setDisplayOrientation(90);
        Log.e("Rotation", "90");
    } 
    else if (nCurrentOrientation == Configuration.ORIENTATION_LANDSCAPE && rotation == Surface.ROTATION_90) {
        System.out.println("We are in landscape mode");
        // parameters.setRotation(0);
        Log.e("Rotation", "0");
        mCamera.setDisplayOrientation(0);
    } 
    else if (nCurrentOrientation == Configuration.ORIENTATION_LANDSCAPE && rotation == Surface.ROTATION_270) {
        System.out.println("Reverse Landscape Mode");
        Log.e("Rotation", "180");
        mCamera.setDisplayOrientation(180);
    } 
    else if (nCurrentOrientation == Configuration.ORIENTATION_PORTRAIT && rotation == Surface.ROTATION_180) {
        System.out.println("Reverse potrait mode");
        Log.e("Rotation", "90");
        mCamera.setDisplayOrientation(90);
    }
    }
    catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
    // _doSomeThingWhenChangeOrientation(nCurrentOrientation);
}
private int _getScreenOrientation() {
    int returnOrientation = 0;
    try {
        returnOrientation = getResources().getConfiguration().orientation;
    } 
    catch (Exception e) {
        System.out.println(e.getMessage());
    }
    return returnOrientation;
}
int orientation = -1;
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
    // TODO Auto-generated method stub
}
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
    float x = sensorEvent.values[0];
    float y = sensorEvent.values[1];
    if (x >= -5 && x < 5) {
        if (y > 0) {
            mDetected_Orientention = PORTRAIT;
            //Log.e("X", "PORTRAIT");
        }
        else {
            mDetected_Orientention = PORTRAIT_REV;
            //Log.e("X", "PORTRAIT_REV");
        }
    } 
    else {
        if (x >= -10 && x < -5) {
            //Log.e("X", "LAND_RIGHT");
            mDetected_Orientention = LANDSCAPE_RIGHT;
        } 
        else {
            //Log.e("X", "LEND_LEFT");
            mDetected_Orientention = LANDSCAPE_LEFT;
        }
    }
}

}

Answer 1

这个答案99%抄袭自Commonsware教程/代码示例。我添加了一个在前后摄像头之间切换的按钮。

预览演示.java

package com.commonsware.android.camera;
import java.io.IOException;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Toast;
public class PreviewDemo extends Activity {
    private static final String TAG = PreviewDemo.class.getSimpleName();
    private SurfaceView preview = null;
    private SurfaceHolder previewHolder = null;
    private Camera camera = null;
    private boolean inPreview = false;
    private boolean cameraConfigured = false;
    int cameraID = 0;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        preview = (SurfaceView) findViewById(R.id.preview);
        previewHolder = preview.getHolder();
        previewHolder.addCallback(surfaceCallback);
        previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }
    @SuppressLint("NewApi")
    @Override
    public void onResume() {
        super.onResume();
        // camera = Camera.open();
        camera = Camera.open(cameraID);
        startPreview();
    }
    @Override
    public void onPause() {
        if (inPreview) {
            camera.stopPreview();
        }
        camera.release();
        camera = null;
        inPreview = false;
        super.onPause();
    }
    private Camera.Size getBestPreviewSize(int width, int height, Camera.Parameters parameters) {
        Camera.Size result = null;
        for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
            if (size.width <= width && size.height <= height) {
                if (result == null) {
                    result = size;
                } else {
                    int resultArea = result.width * result.height;
                    int newArea = size.width * size.height;
                    if (newArea > resultArea) {
                        result = size;
                    }
                }
            }
        }
        return (result);
    }
    private void initPreview(int width, int height) {
        if (camera != null && previewHolder.getSurface() != null) {
            try {
                camera.setPreviewDisplay(previewHolder);
            } catch (Throwable t) {
                Log.e("PreviewDemo-surfaceCallback", "Exception in setPreviewDisplay()", t);
                Toast.makeText(PreviewDemo.this, t.getMessage(), Toast.LENGTH_LONG).show();
            }
            if (!cameraConfigured) {
                Camera.Parameters parameters = camera.getParameters();
                Camera.Size size = getBestPreviewSize(width, height, parameters);
                if (size != null) {
                    parameters.setPreviewSize(size.width, size.height);
                    camera.setParameters(parameters);
                    cameraConfigured = true;
                }
            }
        }
    }
    private void startPreview() {
        Log.d(TAG, "start preview called");
        if (cameraConfigured && camera != null) {
            Log.d(TAG, "stuff works");
            camera.startPreview();
            inPreview = true;
        }
    }
    SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
        public void surfaceCreated(SurfaceHolder holder) {
            // no-op -- wait until surfaceChanged()
        }
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            initPreview(width, height);
            startPreview();
        }
        public void surfaceDestroyed(SurfaceHolder holder) {
            // no-op
        }
    };
    @SuppressLint("NewApi")
    public void switchCamera(View view) {
        Log.d(TAG, "switch called");
        if (inPreview) {
            camera.stopPreview();
        }
        camera.release();
        cameraID = (cameraID + 1) % 2;
        camera = Camera.open(cameraID);
        try {
            camera.setPreviewDisplay(previewHolder);
        } catch (IOException e) {
            e.printStackTrace();
        }
        camera.startPreview();
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
    <android.view.SurfaceView
        android:id="@+id/preview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </android.view.SurfaceView>
    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="switch"
        android:layout_alignParentBottom="true"
        android:onClick="switchCamera" />
</RelativeLayout>