Camera2+TextureView平板首次拍照崩溃：Surface无有效原生Surface问题求助

这个问题我之前适配平板Camera2的时候踩过坑，日志里的Surface had no valid native Surface其实是Legacy Camera模式下的典型问题——平板的Surface初始化节奏和手机不一样，首次拍照时TextureView的Surface还没完全准备好就被Camera2调用了。下面是几个亲测有效的解决办法：

平板的渲染线程通常比手机慢，onSurfaceTextureAvailable回调触发时，Surface可能还没完成底层native资源的初始化。所以在触发拍照前，一定要做双重校验：

// 在拍照按钮的点击事件里加判断
if (textureView.isAvailable() && textureView.getSurfaceTexture().isValid()) {
    // 确认Surface就绪，执行拍照
    takePicture();
} else {
    // 延迟重试，给Surface留足初始化时间
    new Handler(Looper.getMainLooper()).postDelayed(this::takePicture, 250);
}

很多旧款平板会默认 fallback 到Legacy模式，这个模式对Surface的校验比Full/Limited模式严格得多。可以在初始化Camera前先检查硬件级别，优先选择支持高级别模式的相机：

CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
    for (String cameraId : cameraManager.getCameraIdList()) {
        CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
        Integer hardwareLevel = characteristics.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);
        if (hardwareLevel != null && 
            (hardwareLevel == CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_FULL ||
             hardwareLevel == CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED)) {
            // 选定这个相机ID，跳过Legacy模式的相机
            mTargetCameraId = cameraId;
            break;
        }
    }
} catch (CameraAccessException e) {
    e.printStackTrace();
}

如果还是出现崩溃，可以在拍照代码里捕获这个特定异常，然后重建Surface和Camera会话再重试：

try {
    mCaptureSession.capture(mCaptureRequest, mCaptureCallback, null);
} catch (IllegalArgumentException e) {
    if (e.getMessage() != null && e.getMessage().contains("Surface had no valid native Surface")) {
        // 释放旧的SurfaceTexture
        textureView.getSurfaceTexture().release();
        // 创建新的SurfaceTexture并绑定到TextureView
        textureView.setSurfaceTexture(new SurfaceTexture(0));
        // 重新初始化Camera会话
        recreateCameraCaptureSession();
        // 延迟重试拍照
        new Handler(Looper.getMainLooper()).postDelayed(this::takePicture, 300);
    }
}

平板的布局测量耗时更长，建议在onWindowFocusChanged回调里再初始化Camera，确保TextureView已经完成布局和渲染：

private boolean isCameraInitialized = false;

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    super.onWindowFocusChanged(hasFocus);
    if (hasFocus && !isCameraInitialized) {
        // 此时View已经完全显示，Surface初始化更可靠
        initCamera();
        isCameraInitialized = true;
    }
}

内容的提问来源于stack exchange，提问作者Ragini