我使用相机2 API和表面视图遇到了问题。这是一个旧的嵌入式系统,我必须使用surfaceview,原因我在这里无法解释。
我找到了这个样本,它展示了如何完成它:
https://android.googlesource.com/platform/frameworks/base/+/ee699a6/tests/Camera2Tests?autodive=0
我需要在“onCreate”之后延迟启动预览。代码工作没有任何延迟。但是,如果我添加一个延迟,预览永远不会出现(表面回调永远不会被调用)
这是一段不起作用的代码片段:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.surfaceviewtest);
new Handler(Looper.getMainLooper()).postDelayed(new Runnable() {
@Override
public void run() {
startCameraExec();
}
}, 2000);
}
但这有效:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.surfaceviewtest);
startCameraExec();
}
我的startCameraExec只是设置后台线程并设置表面回调
private void startCameraExec() {
Log.d(TAG, "Starting API2 camera...");
// Start a background thread to manage camera requests
mBackgroundThread = new HandlerThread("background");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
mForegroundHandler = new Handler(getMainLooper());
mCameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);
mSurfaceView = (SurfaceView) findViewById(R.id.mainSurfaceView);
mSurfaceView.getHolder().addCallback(mSurfaceHolderCallback);
}
.xml也很简单:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary"
android:orientation="vertical">
<SurfaceView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mainSurfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_centerInParent="true"
android:layout_margin="80dp"
android:onClick="onClickOnSurfaceView" />
</RelativeLayout>
这就是我认为的问题,如果延迟初始化,这永远不会被调用
final SurfaceHolder.Callback mSurfaceHolderCallback = new SurfaceHolder.Callback() {
... a bunch of code
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// On the first invocation, width and height were automatically set to the view's size
if (mCameraId == null) {
// Find the device's back-facing camera and set the destination buffer sizes
try {
for (String cameraId : mCameraManager.getCameraIdList()) {
CameraCharacteristics cameraCharacteristics =
... a bunch of code
我可以解决这个问题的任何线索吗?
谢谢。
您可以尝试在surfaceChanged( { // if (mCameraId == null) {
之后输入延迟
但您必须跟踪获取和启动摄像机流所需的所有条件。如果可能更安全,只能延迟调用开始预览。
我发现了一个更简单的解决方案我隐藏了表面,只是在延迟之后才能看到它。这就是我要找的东西。感谢您的投入。
private void startCameraExec() {
Log.d(TAG, "Starting API2 camera...");
mSurfaceView = (SurfaceView) findViewById(R.id.mainSurfaceView);
// This did the trick :)
mSurfaceView.setVisibility(View.VISIBLE);
mSurfaceView.getHolder().addCallback(mSurfaceHolderCallback);