Why can't i set the visibility of my images in android studio?

Question

my APP should show and/or hide images according to some variables. Here's the code:

final ImageView greenSquare = (ImageView) findViewById(R.id.greensquare);
final ImageView greenBigSquare = (ImageView) findViewById(R.id.greenBIGsquare);

if (a) {
    if (b) {
        b = false;
        a = false;
        greenSquare.setVisibility(View.INVISIBLE);
        greenBigSquare.setVisibility(View.VISIBLE);
    } else {
        b = true;
    }
} else {
    if (c) {
        a = !a;
        greenSquare.setVisibility(View.VISIBLE);
        greenBigSquare.setVisibility(View.INVISIBLE);
    }
}

And here's the XML

<ImageView
    android:id="@+id/greenBIGsquare"
    android:visibility="invisible"
    opencv:srcCompat="@color/colorFollowMe" />

<ImageView
    android:id="@+id/greensquare"
    android:visibility="visible"
    opencv:srcCompat="@color/colorAccent" />

but it doesn't run correctly and it crushes.

Here's the logcat

01-29 20:20:18.487 6535-6667/pinwheel.redblock E/AndroidRuntime: FATAL EXCEPTION: Thread-331 Process: pinwheel.redblock, PID: 6535 android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6556) at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:942) at android.view.ViewGroup.invalidateChild(ViewGroup.java:5081) at android.view.View.invalidateInternal(View.java:12719) at android.view.View.invalidate(View.java:12683) at android.view.View.setFlags(View.java:10640) at android.view.View.setVisibility(View.java:7431) at android.widget.ImageView.setVisibility(ImageView.java:1469) at pinwheel.redblock.MainActivity_Show_camera.onCameraFrame(MainActivity_Show_camera.java:492) at org.opencv.android.CameraBridgeViewBase.deliverAndDrawFrame(CameraBridgeViewBase.java:391) at pinwheel.redblock.PortraitCameraView.access$400(PortraitCameraView.java:21) at pinwheel.redblock.PortraitCameraView$CameraWorker.run(PortraitCameraView.java:289) at java.lang.Thread.run(Thread.java:818)

Can anybody help me? Thank you

Answer 1

尝试使用@UiThread注释方法

Answer 2

try this:

 runOnUiThread(new Runnable() {
     @Override
     public void run() {

        greenSquare.setVisibility(View.INVISIBLE);
        greenBigSquare.setVisibility(View.VISIBLE);

    }
});

also use this in your else block during changing the visibility..

any action involving the user interface must be done in the main or UI thread