我根据教程创建了一个相机应用程序。我使用的预览类来自 api-Demos“CameraPreview”。我添加了来自 here 的修改(预览总是旋转 90°)。所以这就是我设置预览大小的方式:
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
if (display.getRotation() == Surface.ROTATION_0) {
parameters.setPreviewSize(mPreviewSize.height, mPreviewSize.width);
mCamera.setDisplayOrientation(90);
}
if (display.getRotation() == Surface.ROTATION_90) {
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
}
if (display.getRotation() == Surface.ROTATION_180) {
parameters.setPreviewSize(mPreviewSize.height, mPreviewSize.width);
}
if (display.getRotation() == Surface.ROTATION_270) {
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
mCamera.setDisplayOrientation(180);
}
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);
mCamera.startPreview();
}
但预览显示的纵横比错误。是因为上面的代码还是因为我使用的布局?:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="@+id/button_capture"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="@string/capture" />
<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="100dp"
android:layout_height="match_parent"/>
那么如何获得正确的纵横比呢?提前致谢。
附:我从以下位置阅读答案:Android camera preview look strange 但这对我不起作用。
最佳答案
尝试通过添加此功能来更改预览大小:
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.05;
double targetRatio = (double) w/h;
if (sizes==null) return null;
Camera.Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Find size
for (Camera.Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Camera.Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
并根据这些优化值设置尺寸:
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
Camera.Size optimalSize = getOptimalPreviewSize(sizes, getResources().getDisplayMetrics().widthPixels, getResources().getDisplayMetrics().heightPixels);
parameters.setPreviewSize(optimalSize.width, optimalSize.height);
关于android相机预览错误的纵横比,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17804309/