YoKeyword/Fragmentation · critical · RuntimeException

Must extends FragmentActivity/AppCompatActivity and…

Error message

Must extends FragmentActivity/AppCompatActivity and implements ISupportActivity

What it means

SwipeBackActivityDelegate requires its host to be both a FragmentActivity (for fragment operations) and an ISupportActivity (for fragmentation integration). The constructor throws a RuntimeException if either condition fails, since it casts to FragmentActivity and delegates to the support stack.

Solutions

1. Extend SwipeBackActivity from the library, which already satisfies both constraints.
2. Or extend AppCompatActivity/FragmentActivity AND implement ISupportActivity (with SupportActivityDelegate) before using SwipeBackActivityDelegate.

Example fix

// before
public class DetailActivity extends Activity {
// after
public class DetailActivity extends SwipeBackActivity {

if (!(this instanceof FragmentActivity) || !(this instanceof ISupportActivity)) {
    throw new IllegalStateException("SwipeBack host must extend FragmentActivity and implement ISupportActivity");
}

boolean isSwipeBackHost(Activity a) { return a instanceof FragmentActivity && a instanceof ISupportActivity; }

When it happens

Trigger: Instantiating SwipeBackActivityDelegate (or extending SwipeBackActivity using it) from an activity that is not a FragmentActivity or does not implement ISupportActivity.

Common situations: Adding swipe-back to a plain Activity or AppCompatActivity without ISupportActivity; custom base activities missing the ISupportActivity implementation; mixing fragmentation_swipeback with non-support activities.

Related errors

• Must extends FragmentActivity/AppCompatActivity
• Must extends Fragment
• must impl ISupportActivity!
• Threshold value should be between 0 and 1.0
• not attach!

AI-assisted analysis of YoKeyword/Fragmentation@0394930a3e (2026-09-10). Data as JSON: /api/errors/66467275a5cf9999. Report an issue: GitHub.

Appendix: source

Thrown at fragmentation_swipeback/src/main/java/me/yokeyword/fragmentation_swipeback/core/SwipeBackActivityDelegate.java:22

import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import androidx.fragment.app.FragmentActivity;
import android.view.ViewGroup;

import me.yokeyword.fragmentation.ISupportActivity;
import me.yokeyword.fragmentation.SwipeBackLayout;

/**
 * Created by YoKey on 17/6/29.
 */

public class SwipeBackActivityDelegate {
    private FragmentActivity mActivity;
    private SwipeBackLayout mSwipeBackLayout;

    public SwipeBackActivityDelegate(ISwipeBackActivity swipeBackActivity) {
        if (!(swipeBackActivity instanceof FragmentActivity) || !(swipeBackActivity instanceof ISupportActivity))
            throw new RuntimeException("Must extends FragmentActivity/AppCompatActivity and implements ISupportActivity");
        mActivity = (FragmentActivity) swipeBackActivity;
    }

    public void onCreate(Bundle savedInstanceState) {
        onActivityCreate();
    }

    public void onPostCreate(Bundle savedInstanceState) {
        mSwipeBackLayout.attachToActivity(mActivity);
    }

    public SwipeBackLayout getSwipeBackLayout() {
        return mSwipeBackLayout;
    }

    public void setSwipeBackEnable(boolean enable) {
        mSwipeBackLayout.setEnableGesture(enable);
    }

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