AboutActivity.java

package com.whf.messagerelayer.activity;

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.webkit.WebView;

import com.whf.messagerelayer.R;

public class AboutActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about);
        initActionbar();
    }

    private void initActionbar(){
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getItemId() == android.R.id.home){
            finish();
        }
        return super.onOptionsItemSelected(item);
    }
}