本文介绍了试图切换回相机前面，但得到的异常的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
试图切换回相机前面，但得到的异常。找不到 这个问题请检查并帮助..
我的code： -
公共类AndroidVideoCapture延伸活动{
私有静态最后字符串变量=CameraRecorderActivity;
私人相机myCamera;
私人MyCameraSurfaceView myCameraSurfaceView;
私人MediaRecorder mediaRecorder;
私有静态字符串VAL =是;
私人按钮useOtherCamera;
按钮myButton的;
SurfaceHolder surfaceHolder;
布尔记录;
/ **第一次创建活动时调用。 * /
@覆盖
公共无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
记录= FALSE;
的setContentView（R.layout.activity_android_video_capture）;
useOtherCamera =（按钮）findViewById（R.id.useOtherCamera）;
useOtherCamera.setOnClickListener（
新View.OnClickListener（）{
@覆盖
公共无效的onClick（视图v）{
//获取相机为preVIEW
myCamera = getCameraInstance（）;
}
}）;
的FrameLayout myCamera preVIEW =（的FrameLayout）findViewById（R.id.videoview）;
myCamera preview.addView（myCameraSurfaceView）;
为myButton =（按钮）findViewById（R.id.mybutton）;
myButton.setOnClickListener（myButtonOnClickListener）;
myButton.setOnClickListener（myButtonOnClickListener）;
如果（myCamera == NULL）{
的System.out.println（打印TRACK - 7）;
Toast.makeText（AndroidVideoCapture.this，
轮不到相机，
Toast.LENGTH_LONG）.show（）;
}
myCameraSurfaceView =新MyCameraSurfaceView（这一点，myCamera）;
}
Button.OnClickListener myButtonOnClickListener
=新Button.OnClickListener（）{
@覆盖
公共无效的onClick（视图v）{
// TODO自动生成方法存根
如果（录音）{
//停止录制并发行摄像头
mediaRecorder.stop（）; //停止录制
releaseMediaRecorder（）; //释放MediaRecorder对象
//保存退出后，
完（）;
}其他{
//发布MediaRecorder开始前摄像头
releaseCamera（）;
如果（！prepareMediaRecorder（））{
Toast.makeText（AndroidVideoCapture.this，
在失败prepareMediaRecorder（）\ N - ！结束 - ，
Toast.LENGTH_LONG）.show（）;
完（）;
}
mediaRecorder.start（）;
记录= TRUE;
myButton.setText（STOP）;
}
}};
公众诠释getFrontCameraId（）{
CameraInfo CI =新CameraInfo（）;
的for（int i = 0; I＆LT; Camera.getNumberOfCameras（）;我++）{
Camera.getCameraInfo（I，CI）;
如果（（VAL ==是）及及（ci.facing == CameraInfo.CAMERA_FACING_FRONT））
{
VAL =无;
返回我;
}
}
返回CameraInfo.CAMERA_FACING_BACK; //没有前置摄像头发现
}
公共相机getCameraInstance（）{
// TODO自动生成方法存根
相机C = NULL;
尝试 {
INT指数= getFrontCameraId（）;
如果（索引！= -1）
{
C = Camera.open（指数）;
// C = Camera.open（）; //尝试获取摄像头实例
}其他{
C = Camera.open（指数）;
}
}
赶上（例外五）{
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
//相机无法使用（使用或不存在）
}
返回℃; //如果相机是不可用，则返回null
}
私人布尔prepareMediaRecorder（）{
myCamera = getCameraInstance（）;
mediaRecorder =新MediaRecorder（）;
myCamera.unlock（）;
mediaRecorder.setCamera（myCamera）;
mediaRecorder.setAudioSource（MediaRecorder.AudioSource.CAMCORDER）;
mediaRecorder.setVideoSource（MediaRecorder.VideoSource.CAMERA）;
mediaRecorder.setProfile（CamcorderProfile.get（CamcorderProfile.QUALITY_LOW））;
mediaRecorder.setOutputFile（/ SD卡/ myvideo.mp4）;
mediaRecorder.setMaxDuration（60000）; //设置最大持续时间60秒。
mediaRecorder.setMaxFileSize（5000000）; //设置最大文件大小为5M
mediaRecorder.set previewDisplay（myCameraSurfaceView.getHolder（）getSurface（））;
尝试 {
mediaRecorder prepare（）。
}赶上（IllegalStateException异常E）{
releaseMediaRecorder（）;
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
返回false;
}赶上（IOException异常E）{
releaseMediaRecorder（）;
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
返回false;
}
返回true;
}
@覆盖
保护无效的onPause（）{
super.onPause（）;
releaseMediaRecorder（）; //如果您使用的是MediaRecorder，先将它
releaseCamera（）; //在暂停时立即松开相机
}
私人无效releaseMediaRecorder（）{
如果（mediaRecorder！= NULL）{
mediaRecorder.reset（）; //清晰的记录配置
mediaRecorder.release（）; //释放录像机对象
mediaRecorder = NULL;
myCamera.lock（）; //锁定相机以备后用
}
}
私人无效releaseCamera（）{
如果（myCamera！= NULL）{
myCamera.release（）; //释放相机用于其它应用
myCamera = NULL;
}
}
公共类MyCameraSurfaceView扩展了SurfaceView实现SurfaceHolder.Callback {
私人SurfaceHolder mHolder;
私人相机mCamera;
公共MyCameraSurfaceView（上下文的背景下，相机摄像头）{
超（上下文）;
mCamera =摄像头;
//安装SurfaceHolder.Callback所以我们得到通知时，该
//下垫面创建和销毁。
mHolder = getHolder（）;
mHolder.addCallback（本）;
//德precated设置，但在Android上之前的版本3.0所需
mHolder.setType（SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS）;
}
@覆盖
公共无效surfaceChanged（SurfaceHolder持有人，INT格式，诠释权重，
INT高度）{
//如果你的preVIEW可以改变或旋转，把这些事件的关心在这里。
//确保调整或重新格式化之前停止preVIEW。
如果（mHolder.getSurface（）== NULL）{
// preVIEW表面不存在
返回;
}
在进行更改之前//停止preVIEW
尝试 {
mCamera.stop preVIEW（）;
}赶上（例外五）{
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
//忽略：试图阻止一个不存在的preVIEW
}
//做任何调整大小，旋转或重新格式化这里的变化
//启动preVIEW使用新设置
尝试 {
mCamera.set previewDisplay（mHolder）;
mCamera.start preVIEW（）;
}赶上（例外五）{
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
}
}
@覆盖
公共无效surfaceCreated（SurfaceHolder持有者）{
// TODO自动生成方法存根
//表面有被创建，现在告诉相机在哪里画preVIEW。
尝试 {
mCamera.set previewDisplay（保持器）;
mCamera.start preVIEW（）;
}赶上（IOException异常E）{
Log.d（TAG，错误设置摄像头preVIEW：+ e.getMessage（））;
}
}
@覆盖
公共无效surfaceDestroyed（SurfaceHolder持有者）{
// TODO自动生成方法存根
}
}
}
解决方案
切换到其他前停止拍照previous例如：
如果（相机！= NULL）{
camera.stop preVIEW（）;
camera.set previewCallback（空）;
camera.release（）;
摄像头= NULL;
surfaceholder.removeCallback（CameraActivity.this）;
surfaceholder = NULL;
}
和完成当前摄像头的活动，呼吁启动相同的摄像头活动的意图。
Trying to switch camera back to front but getting exception. cant find the problem Please Check and help..
My Code:-
public class AndroidVideoCapture extends Activity{
private static final String TAG = "CameraRecorderActivity";
private Camera myCamera;
private MyCameraSurfaceView myCameraSurfaceView;
private MediaRecorder mediaRecorder;
private static String val="yes";
private Button useOtherCamera;
Button myButton;
SurfaceHolder surfaceHolder;
boolean recording;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
recording = false;
setContentView(R.layout.activity_android_video_capture);
useOtherCamera = (Button) findViewById(R.id.useOtherCamera);
useOtherCamera.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
//Get Camera for preview
myCamera = getCameraInstance();
}
});
FrameLayout myCameraPreview = (FrameLayout)findViewById(R.id.videoview);
myCameraPreview.addView(myCameraSurfaceView);
myButton = (Button)findViewById(R.id.mybutton);
myButton.setOnClickListener(myButtonOnClickListener);
myButton.setOnClickListener(myButtonOnClickListener);
if(myCamera == null){
System.out.println("PRINT TRACK--7 ");
Toast.makeText(AndroidVideoCapture.this,
"Fail to get Camera",
Toast.LENGTH_LONG).show();
}
myCameraSurfaceView = new MyCameraSurfaceView(this, myCamera);
}
Button.OnClickListener myButtonOnClickListener
= new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(recording){
// stop recording and release camera
mediaRecorder.stop(); // stop the recording
releaseMediaRecorder(); // release the MediaRecorder object
//Exit after saved
finish();
}else{
//Release Camera before MediaRecorder start
releaseCamera();
if(!prepareMediaRecorder()){
Toast.makeText(AndroidVideoCapture.this,
"Fail in prepareMediaRecorder()!\n - Ended -",
Toast.LENGTH_LONG).show();
finish();
}
mediaRecorder.start();
recording = true;
myButton.setText("STOP");
}
}};
public int getFrontCameraId() {
CameraInfo ci = new CameraInfo();
for (int i = 0 ; i < Camera.getNumberOfCameras(); i++) {
Camera.getCameraInfo(i, ci);
if ((val=="yes") && (ci.facing == CameraInfo.CAMERA_FACING_FRONT))
{
val="no";
return i;
}
}
return CameraInfo.CAMERA_FACING_BACK; // No front-facing camera found
}
public Camera getCameraInstance(){
// TODO Auto-generated method stub
Camera c = null;
try {
int index = getFrontCameraId();
if (index != -1)
{
c = Camera.open(index);
// c = Camera.open(); // attempt to get a Camera instance
}else{
c = Camera.open(index);
}
}
catch (Exception e){
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
private boolean prepareMediaRecorder(){
myCamera = getCameraInstance();
mediaRecorder = new MediaRecorder();
myCamera.unlock();
mediaRecorder.setCamera(myCamera);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_LOW));
mediaRecorder.setOutputFile("/sdcard/myvideo.mp4");
mediaRecorder.setMaxDuration(60000); // Set max duration 60 sec.
mediaRecorder.setMaxFileSize(5000000); // Set max file size 5M
mediaRecorder.setPreviewDisplay(myCameraSurfaceView.getHolder().getSurface());
try {
mediaRecorder.prepare();
} catch (IllegalStateException e) {
releaseMediaRecorder();
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
return false;
} catch (IOException e) {
releaseMediaRecorder();
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
return false;
}
return true;
}
@Override
protected void onPause() {
super.onPause();
releaseMediaRecorder(); // if you are using MediaRecorder, release it first
releaseCamera(); // release the camera immediately on pause event
}
private void releaseMediaRecorder(){
if (mediaRecorder != null) {
mediaRecorder.reset(); // clear recorder configuration
mediaRecorder.release(); // release the recorder object
mediaRecorder = null;
myCamera.lock(); // lock camera for later use
}
}
private void releaseCamera(){
if (myCamera != null){
myCamera.release(); // release the camera for other applications
myCamera = null;
}
}
public class MyCameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
public MyCameraSurfaceView(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);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int weight,
int height) {
// 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){
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
// ignore: tried to stop a non-existent preview
}
// 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 setting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
// 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());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}
}
解决方案
Stop the camera previous instance before switching to other :
if (camera != null) {
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
camera = null;
surfaceholder.removeCallback(CameraActivity.this);
surfaceholder = null;
}
And finish current camera activity, call start intent of same camera activity.
这篇关于试图切换回相机前面，但得到的异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！