Secure Android Activity that does not allow clicks when in the background, and prevents screenshots.

SecureActivity.java

package pro.schmid.android.secureapp;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.WindowManager;

public class SecureActivity extends Activity {

  private ViewGroup mRootView;
	private View mBlackScreen;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		// Prevent screenshots
		// (But not on Gingerbread)
		if (android.os.Build.VERSION.SDK_INT != android.os.Build.VERSION_CODES.GINGERBREAD && android.os.Build.VERSION.SDK_INT != android.os.Build.VERSION_CODES.GINGERBREAD_MR1) {
			getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
		}

		// The root view must have the flag android:filterTouchesWhenObscured set to true.
		setContentView(R.layout.activity_main);

		// Init the black screen
		mBlackScreen = new View(this);
		LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
		mBlackScreen.setLayoutParams(layoutParams);
		mBlackScreen.setBackgroundColor(Color.BLACK);
		mBlackScreen.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				// Catch click and do nothing
			}
		});

		// Get the root view
		mRootView = (ViewGroup) getWindow().findViewById(android.R.id.content);
	}

	@Override
	protected void onPause() {
		addBlackScreen();
		super.onPause();
	}

	@Override
	protected void onResume() {
		removeBlackScreen();
		super.onResume();
	}

	private void addBlackScreen() {
		mRootView.addView(mBlackScreen);
	}

	private void removeBlackScreen() {
		mRootView.removeView(mBlackScreen);
	}
}