android中关于camera开发的一些问题
最近开发android中camera程序中遇到的问题一直未能解决，求各位大侠帮帮忙
代码如下:
public class CameraTActivity extends Activity implements OnClickListener,SurfaceHolder.Callback{
/** Called when the activity is first created. */
private Button camera_start,camera_pause;
public Camera camera ;
public Camera.Parameters parameters ;
private SurfaceHolder surfaceHolder;
private SurfaceView surfaceView;
private SurfaceView camera_play_surfaceview;
private int screenWidth,screenHeight;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initView();
System.out.println("start---------");
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
try {
startCamera();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
System.out.println("create");
if(camera==null){
camera = Camera.open();
}
System.out.println("camera start");
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
if(camera!=null){
camera.stopPreview();
camera.release();
}
}
public void initView(){
surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
}
/**
* Creates a new Camera object to access the first back-facing camera on the device.
* If the device does not have a back-facing camera, this returns null.
* @throws IOException */
private void startCamera() throws IOException{
parameters = camera.getParameters();
screenWidth = surfaceView.getWidth();
screenHeight = surfaceView.getHeight();
parameters.setPreviewSize(screenWidth, screenHeight); // 设置预览照片的大小
parameters.setPreviewFpsRange(60, 75); // 每秒显示20~30帧
parameters.setPictureFormat(ImageFormat.NV21); // 设置图片格式
parameters.setPictureSize(screenWidth, screenHeight); // 设置照片的大小
// camera.setParameters(parameters); // android2.3.3以后不需要此行代码
camera.setPreviewDisplay(surfaceHolder); // 通过SurfaceView显示取景画面
camera.setPreviewCallback(cPreview); // 设置回调的类
camera.startPreview(); // 开始预览
camera.autoFocus(null); // 自动对焦
}
}
log信息如下:
01-02 01:21:13.380: WARN/System.err(3155): java.lang.RuntimeException: startPreview failed
01-02 01:21:13.390: WARN/System.err(3155): at android.hardware.Camera.startPreview(Native Method)
01-02 01:21:13.390: WARN/System.err(3155): at com.camera.CameraTActivity.startCamera(CameraTActivity.java:100)
01-02 01:21:13.390: WARN/System.err(3155): at com.camera.CameraTActivity.surfaceChanged(CameraTActivity.java:40)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.SurfaceView.updateWindow(SurfaceView.java:549)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.SurfaceView.dispatchDraw(SurfaceView.java:348)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.drawChild(ViewGroup.java:1645)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1374)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.drawChild(ViewGroup.java:1645)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1374)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.View.draw(View.java:7165)
01-02 01:21:13.390: WARN/System.err(3155): at android.widget.FrameLayout.draw(FrameLayout.java:357)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.drawChild(ViewGroup.java:1647)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1374)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.drawChild(ViewGroup.java:1645)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1374)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.View.draw(View.java:7165)
01-02 01:21:13.390: WARN/System.err(3155): at android.widget.FrameLayout.draw(FrameLayout.java:357)
01-02 01:21:13.390: WARN/System.err(3155): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1862)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewRoot.draw(ViewRoot.java:1592)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewRoot.performTraversals(ViewRoot.java:1301)
01-02 01:21:13.390: WARN/System.err(3155): at android.view.ViewRoot.handleMessage(ViewRoot.java:1931)
01-02 01:21:13.390: WARN/System.err(3155): at android.os.Handler.dispatchMessage(Handler.java:99)
01-02 01:21:13.390: WARN/System.err(3155): at android.os.Looper.loop(Looper.java:130)
01-02 01:21:13.390: WARN/System.err(3155): at android.app.ActivityThread.main(ActivityThread.java:3683)
01-02 01:21:13.390: WARN/System.err(3155): at java.lang.reflect.Method.invokeNative(Native Method)
01-02 01:21:13.390: WARN/System.err(3155): at java.lang.reflect.Method.invoke(Method.java:507)
01-02 01:21:13.390: WARN/System.err(3155): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-02 01:21:13.390: WARN/System.err(3155): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-02 01:21:13.390: WARN/System.err(3155): at dalvik.system.NativeStart.main(Native Method)
[解决办法]
private Button camera_start,camera_pause; 这俩button 你是不是find下？
[解决办法]
Camera.open是成功的吗？Camera的permission加了吗？
[解决办法]
at android.view.ViewRoot.handleMessage(ViewRoot.java:1931)
看这我估计是有操作阻碍了UI线程
你最好在UI有变化是用Handler机制来通知一下，这样就不会阻碍UI了，你可以打断点看看程序到底在什么地方报错
