无法更新用户界面(使用openCV)CalledFromWrongThreadException

Question

我正在用OpenCV库实现一个应用程序。处理完相机的inputFrame后，我想更新我的TextView。然而，我得到以下错误：

08-01 17:01:45.085: E/AndroidRuntime(16284): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

以下是我的应用程序的简化代码：

(...IMPORTS...)
public class ObjectTracker extends Activity implements CvCameraViewListener2, OnClickListener {
TextView resultTextView;
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
    @Override
    public void onManagerConnected(int status) {
        switch (status) {
            case LoaderCallbackInterface.SUCCESS:
            {
                Log.i(TAG, "OpenCV loaded successfully");
                myJavaCameraView.enableView();
            } break;
            default:
            {
                super.onManagerConnected(status);
            } break;
        }
    }
};
public ObjectTracker() {
    Log.i(TAG, "Instantiated new " + this.getClass());
}
@Override
public void onCreate(Bundle savedInstanceState) {
    (...)
    resultTextView = (TextView)           
    findViewById(R.id.activity_object_tracker_native_textview_result);
}
@Override
public void onPause()
{
    super.onPause();
    if (myJavaCameraView != null)
        myJavaCameraView.disableView();
}
@Override
public void onResume()
{
    super.onResume();
    OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_6, this, mLoaderCallback);
}
public void onDestroy() {
    super.onDestroy();
    if (myJavaCameraView != null)
        myJavaCameraView.disableView();
}
public void onCameraViewStarted(int width, int height) {
}
public void onCameraViewStopped() {
}
public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
    (...)
    return trackFilteredObject(filteredFrame, newInputFrame);
}
public Mat trackFilteredObject(Mat filteredFrame, Mat inputFrame)
{
    (...)
    //HERE I WANT TO UPDATE MY TEXT VIEW
    return inputImage;
}

}

我不知道应该把更新代码放在哪里以消除这个错误。有人能帮我吗？

Answer 1

UI内容只能从主UI线程进行修改。回调的trackFilteredObject方法（更新TextView）显然是从后台线程调用的。

要解决此问题，您可以使用Activity#runOnUiThread方法，该方法允许您发布要在UI线程上执行的可运行程序。

尝试更换

//HERE I WANT TO UPDATE MY TEXT VIEW

通过

runOnUiThread(new Runnable() {
    public void run() {
        //HERE I WANT TO UPDATE MY TEXT VIEW
    }
});

Answer 2

我找到了一个解决方案：

public Mat trackFilteredObject(Mat filteredFrame, Mat inputFrame)
{
    (...)
    runOnUiThread(new Runnable() {
        public void run() {
            //HERE I UPDATE TEXT VIEW
        }
    });
    return inputImage;
}

感谢@fiddler 的帮助