如果有人知道如何在使用MediaRecorder时在前后摄像头之间切换。我为这个函数定义了一个按钮，但是不知道如何定义onclickListener。
总活动如下：
import java.io.File;
import java.io.IOException;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.hardware.Camera;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.SurfaceHolder.Callback;
import android.view.View.OnClickListener;
import android.widget.Button;
public class Test_cameraActivity extends Activity implements Callback {
// Camera variables to fiddle with video preview.
// private Camera cam;
// Viewholders etc
private SurfaceHolder recordViewHolder;
private SurfaceView recordSurface;
private int width, height;
// Button
private Button recordBut;
private Button switchBut;
private Button libraryBut;
private final static String DIRECTORY = "/hdrecorder"; // Directory where
// the film is
// stored
private final static String recordFileName = "/hdtestfile.mp4";
private final static String saveFileName = "/hdsavefile.mp4";
private MyMediaRecorder recorder = null;
private final static String LOG_TAG = "HD Recorder";
private String filePath;
// Activity overrides
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// *******************************************
// fullscreen mode
// *******************************************
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
// *******************************************
setContentView(R.layout.main);
File dir = new File(Environment.getExternalStorageDirectory()
+ DIRECTORY);
if (!dir.exists()) {
if (dir.mkdir()) {
Log.v(LOG_TAG, "Created directory");
} else {
Log.v(LOG_TAG, "Failed to create Directory");
}
}
File videoFile = new File(Environment.getExternalStorageDirectory()
+ DIRECTORY + recordFileName);
if (!videoFile.exists()) {
videoFile.delete(); // Reset recording
}
filePath = videoFile.getAbsolutePath();
Log.v(LOG_TAG, "PATH:" + filePath);
Log.v(LOG_TAG, "PATH:" + filePath);
recordSurface = (SurfaceView) findViewById(R.id.videoSurface);
recordBut = (Button) findViewById(R.id.RecordBut);
recordBut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (recorder.getState() != MyMediaRecorder.RECORDING) {
startRecord();
} else {
stopRecord();
recorder.release();
moveRecordFileToSave();
if (recorder == null) {
Log.v(LOG_TAG, "Recorder is null");
}
Log.v(LOG_TAG, "Value of recorder:" + recorder);
createRecorder();
initiateRecorder(recordViewHolder, width, height);
}
}
});
switchBut = (Button) findViewById(R.id.SwitchBut);
switchBut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
}
});
libraryBut = (Button) findViewById(R.id.LibraryBut);
libraryBut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(Test_cameraActivity.this,
FileExplorer.class);
Test_cameraActivity.this.startActivity(intent);
}
});
recordViewHolder = recordSurface.getHolder();
recordViewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
recordViewHolder.addCallback(this);
// setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
createRecorder();
}
@Override
protected void onStart() {
super.onStart();
Log.v(LOG_TAG, "OnStart");
if (recorder != null) {
if (recorder.getState() == MyMediaRecorder.RELEASED) {
createRecorder();
}
}
Log.v(LOG_TAG, "SurfaceView create initiated. OnStart Done");
}
@Override
protected void onStop() {
super.onStop();
Log.v(LOG_TAG, "onStop received");
forceStopRecorder();
}
// General Helpers.
private void createRecorder() {
recorder = new MyMediaRecorder();
}
private void startRecord() {
if (recorder.getState() != MyMediaRecorder.PREPARED) {
Log.e(LOG_TAG, "Not recordable yet");
return;
}
recorder.start();
Log.v(LOG_TAG, "Recording started");
recordBut.setText("Stop Record");
}
private void stopRecord() {
Log.v(LOG_TAG, "Stop of recorder");
if (recorder.getState() == MyMediaRecorder.RECORDING) {
recorder.stop();
}
recorder.reset();
recordBut.setText("Record");
}
private void initiateRecorder(SurfaceHolder holder, int width, int height) {
Log.v(LOG_TAG, "H: " + height + " W:" + width);
if (recorder.getState() != MyMediaRecorder.INITIAL) {
Log.v(LOG_TAG, "Dude - not existing MediaRecorder - quitting");
return;
}
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setOutputFile(this.filePath);
recorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
recorder.setVideoSize(width, height);
recorder.setVideoFrameRate(24);
recorder.setPreviewDisplay(holder.getSurface());
Log.d(LOG_TAG, "Preview restarted");
try {
recorder.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// isPrepared = true;
}
private void forceStopRecorder() {
Log.v(LOG_TAG, "Force release of recorder");
if (recorder.getState() != MyMediaRecorder.RELEASED) {
stopRecord();
recorder.release();
}
}
private void moveRecordFileToSave() {
File source = new File(filePath);
File dest = new File(Environment.getExternalStorageDirectory()
+ DIRECTORY + saveFileName);
if (dest.exists()) {
Log.v(LOG_TAG, "Delete old save file");
dest.delete();
}
source.renameTo(dest);
}
// ***** Implementing Callback ********/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
recordViewHolder = holder;
this.width = width;
this.height = height;
if (recorder.getState() == MyMediaRecorder.RECORDING) {
stopRecord();
}
if (recorder.getState() == MyMediaRecorder.PREPARED) {
recorder.reset();
}
initiateRecorder(holder, width, height);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.v(LOG_TAG, "Surface is created: Path to use" + filePath);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.v(LOG_TAG, "Surface is Destroyed");
forceStopRecorder();
}
}
答案 0 :(得分：8)
我有一些可能也有帮助的东西，为了跳转到另一台相机，请按照以下方法：
public void flipit() {
//myCamera is the Camera object
if (Camera.getNumberOfCameras()>=2) {
myCamera.stopPreview();
myCamera.release();
//"which" is just an integer flag
switch (which) {
case 0:
myCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_FRONT);
which = 1;
break;
case 1:
myCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);
which = 0;
break;
}
try {
myCamera.setPreviewDisplay(mHolder);
//"this" is a SurfaceView which implements SurfaceHolder.Callback,
//as found in the code examples
myCamera.setPreviewCallback(this);
myCamera.startPreview();
} catch (IOException exception) {
myCamera.release();
myCamera = null;
}
}
}
现在......对于魔术，请不要从主线程中调用此方法。相反，这个方法必须从一个单独的线程开始，我的代码执行此操作：
//btn is a Button that the user clicks on
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//onClick is invoked from main thread
//kick-off a different Thread to handle this call
Thread t = new Thread() {
public void run() {
//myViewer is the SurfaceView object which uses
//the camera
myViewer.flipit();
}
};
t.start();
}
});
我在Android 4.1.1上测试了这个，所以我觉得它可能适合你。 （或者直到谷歌决定打破相机打开/关闭/释放/解锁/重新连接/ surfaceholder / onPause / onResume /等等......的方式）
答案 1 :(得分：0)
首先，检查您的设备是否有多个摄像头：
Camera.getNumberOfCameras();
然后，分配一个camId值：
camId = Camera.CameraInfo.CAMERA_FACING_BACK;
或
camId = Camera.CameraInfo.CAMERA_FACING_FRONT;
然后创建一个新的Camera对象来访问特定的硬件相机（camId）。
mCamera = Camera.open(camId);
希望这有帮助！