android - setParameters() 不支持在 surfaceChanged() 中传递的宽度和高度？

Question

从方法 surfaceChanged() 调用 Camera.setParameters() 时出现 RuntimeException 错误。我看到其他帖子也有同样的问题，但没有找到明确的解决方案: Issue with setting the parameters to camera

我的问题是:

1. 为什么要在 surfaceCreated() 之后立即调用 surfaceChanged()？在 surfaceCreated() 中启动预览是违反直觉的(至少对我而言)，只是停止它并在 surfaceChanged() 中重新启动另一个预览。

2. 第一次调用surfaceChanged()时，传入的宽高是什么决定的？正如上述帖子中所建议的，并在我的实验中得到验证，Camera.setParameters() 不一定支持这些值。请参阅下面的代码 fragment 和日志信息。

3. 在调用 surfaceChanged() 之前，有没有办法保证 Camera.setParameters() 支持宽度和高度值？可以在 surfaceChanged() 中添加代码来确保这一点。例如，可以将 w 和 h 与所有支持的预览尺寸进行比较，并更改为最接近的支持值。但是，这样做会影响性能。

下面列出了我的代码 fragment 和 LogCat 输出。日志记录信息表明 surfaceChanged() 中的 Camera.setParameters() 导致了错误。如果我注释掉调用 setParameters() 的行，我就不会再看到错误消息。

[编辑:我正在 Amazon Kindle Fire HD 上进行测试。 Android版本为4.0.3，API 15]

代码 fragment :

public void surfaceCreated(SurfaceHolder holder) {
    // Log & debug
    Log.d(TAG, "surfaceCreated() is called");

    // The Surface has been created, now tell the camera where to draw the preview.
    try {
        mCamera.setPreviewDisplay(mHolder);
        mCamera.startPreview();
    } catch (IOException e) {
        Log.d(TAG, "surfaceCreated(): " + e.getMessage());
    }

    if (mHolder.getSurface() == null) {
        Log.d(TAG, "surfaceCreated(): preview surface does not exist yet!");
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // Log & debug
    Log.d(TAG, "surfaceDestroyed() is called");

    // Stop preview and release camera 
    if (holder.getSurface() != null) {
        mCamera.stopPreview();
        //mCamera.release();  //should we release camera here?
        //mCamera = null;
    }
    else {
        Log.d(TAG, "surfaceDestroyed(): preview surface does not exist");
    }
}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    // Log and debug
    Log.d(TAG, "surfaceChanged() is called with width = " + w);
    Log.d(TAG, "surfaceChanged() is called with height = " + 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 (holder.getSurface() == null) {
      Log.d(TAG, "surfaceChanged(): preview surface does not exist");
      return;
    }

    // stop preview before making changes
    try {
        mCamera.stopPreview();
    } catch (Exception e) {
        Log.d(TAG, "surfaceChanged(): tried to stop a non-existent preview " + e.getMessage());
    }

    // set preview size and make any resize, rotate or
    // reformatting changes here
    Camera.Parameters params = mCamera.getParameters();
    List<Size> mSizes = params.getSupportedPreviewSizes();

    // list all 25 supported preview sizes
    // i==25 will cause an "IndexOutofBoundsException"
    for (int i=0; i<25; i++) {
        Size mSize  = mSizes.get(i);
        if (mSize == null) break;
        Log.d(TAG, "surfaceChanged() i = " + i);
        Log.d(TAG, "surfaceChanged() preview width = " + mSize.width);
        Log.d(TAG, "surfaceChanged() preview height = " + mSize.height);
    }
    Size       mSize  = mSizes.get(0);
    if(mSize != null) { //make sure we don't pull a NullException.
        if (w > mSize.width) w  = mSize.width;
        if (h > mSize.height) h = mSize.height;
        params.setPreviewSize(w, h); //set the size, since we know it. 
    } 
    mCamera.setParameters(params); //set the parameters now. 

    // start preview with new settings
    try {
        mCamera.setPreviewDisplay(holder);
        mCamera.startPreview();
    } catch (Exception e){
        Log.d(TAG, "surfaceChanged() restart preview " + e.getMessage());
    }
}

LogCat 输出:

02-13 10:46:08.113: D/CameraPreview(2886): surfaceCreated() is called
02-13 10:46:08.496: D/CameraPreview(2886): surfaceChanged() is called with width = 1072
02-13 10:46:08.496: D/CameraPreview(2886): surfaceChanged() is called with height = 705
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 0
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 1280
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 1
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 960
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 2
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 800
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 3
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 576
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 4
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 5
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 768
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 576
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 6
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 640
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 7
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 320
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 240
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 8
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 352
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 288
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 9
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 240
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 160
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 10
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 176
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 144
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 11
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 160
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 120
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 12
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 128
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 96
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 13
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 1280
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 14
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 800
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 15
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 576
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 16
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 576
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 768
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 17
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 720
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 18
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 480
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 640
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 19
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 288
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 352
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 20
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 240
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 320
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 21
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 240
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 160
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 22
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 144
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 176
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 23
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 120
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 160
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() i = 24
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview width = 96
02-13 10:46:08.941: D/CameraPreview(2886): surfaceChanged() preview height = 128
02-13 10:46:08.957: D/AndroidRuntime(2886): Shutting down VM
02-13 10:46:08.957: W/dalvikvm(2886): threadid=1: thread exiting with uncaught exception (group=0x40a6c1f8)
02-13 10:46:08.965: E/AndroidRuntime(2886): FATAL EXCEPTION: main
02-13 10:46:08.965: E/AndroidRuntime(2886): java.lang.RuntimeException: setParameters failed
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.hardware.Camera.native_setParameters(Native Method)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.hardware.Camera.setParameters(Camera.java:1295)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at com.xyz.camera.CameraPreview.surfaceChanged(CameraPreview.java:109)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.SurfaceView.updateWindow(SurfaceView.java:544)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.SurfaceView.access$000(SurfaceView.java:81)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:169)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:590)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1630)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2462)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.os.Looper.loop(Looper.java:137)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at android.app.ActivityThread.main(ActivityThread.java:4486)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at java.lang.reflect.Method.invokeNative(Native Method)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at java.lang.reflect.Method.invoke(Method.java:511)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
02-13 10:46:08.965: E/AndroidRuntime(2886):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

你可能遇到的问题之一是，既然你使用的是 api 15，那么你应该使用 getSupportedVideoSizes()，因为它来自 api 11。我在某些设备上设置参数时遇到了类似的问题(运行 honeycomb 及以上版本的)因为预览大小和支持的视频大小并不总是相同。

编辑::关于您的评论:我会为您的测试设备输出所有支持的预览大小。你已经拥有了。然后我会拿一个(例如:你得到的第二个)并静态设置它用于测试目的

例如:

for int (i = 0; i < mSizes.size(); i ++)
    {
        Log each size;
    }

从中取一个随机大小:例如 480 x 800 并设置它

    params.setPreviewSize(480, 800);

这将明确告诉您设置预览大小是否会显示正确的大小。

编辑2: 我会再次更新我的答案以澄清我的评论

在 onSurfaceChanged 内部有两个变量

int width = 0;
int height = 0;

然后在你的 if 语句中

if (w > mSize.width) width = mSize.width;
if (h > mSize.height) height = mSize.height;

你所做的也相当于

mSizes.get(mSize.size() -1)。因为你 w 和 h 总是会大于 mSize.width 和 mSize.height

编辑 3:好的，根据您的意见。你想在 onSufaceCreated() 里面初始化相机并将 setPreviewSize(w,h) 更改为 setPreviewSize(mSizes.get(mSizes.size() -1).width, mSizes.get(mSizes.size() -1).height);

然后添加一个函数，将surfaceView设置为你想要的任何大小()

surfaceParams = surfaceView.getLayoutParameters();
surfaceParams.setWidth(somewidthyouwant);
surfaceParams.setHeight(someHeightYouWant);
surfaceView.setLayoutParams(surfaceParams);

这会将您的表面 View 设置为您想要的任何大小。