MainActivity.java

package com.ywwxhz.activitys;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.view.KeyEvent;
import android.widget.Toast;

import com.ywwxhz.cnbetareader.R;
import com.ywwxhz.fragments.NavigationDrawerFragment;

import de.keyboardsurfer.android.widget.crouton.Crouton;

public class MainActivity extends BaseToolBarActivity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    /**
     * Fragment managing the behaviors, interactions and presentation of the navigation drawer.
     */
    private NavigationDrawerFragment mNavigationDrawerFragment;
    private int current = -1;
    private long lastpress;
    public boolean changeTheme;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mNavigationDrawerFragment = (NavigationDrawerFragment)
                getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
               R.id.navigation_drawer,
                (DrawerLayout) findViewById(R.id.drawer_layout));
        changeTheme = false;
//        if(PrefKit.getBoolean(this,R.string.pref_auto_update_key,false)) {
//            toolbar.postDelayed(new Runnable() {
//                @Override
//                public void run() {
//                    UpdateHelper.build(MainActivity.this, MyApplication.getInstance().getUpdateUrl())
//                            .check();
//                }
//            }, 500);
//        }
    }

    @Override
    public void onNavigationDrawerItemSelected(Fragment fragment,int pos) {
        if(fragment!=null&¤t!=pos){
            Crouton.clearCroutonsForActivity(this);
            getSupportFragmentManager().beginTransaction().replace(R.id.content, fragment).commit();
            current = pos;
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if(keyCode==KeyEvent.KEYCODE_BACK){
            if(mNavigationDrawerFragment.isDrawerOpen()){
                mNavigationDrawerFragment.closeDrawer();
                return true;
            }else if(current != 0){
                mNavigationDrawerFragment.onBackPassed();
                return true;
            }
            if(System.currentTimeMillis() - lastpress < 1000) {
                this.finish();
            }else {
                lastpress = System.currentTimeMillis();
                Toast.makeText(this, "再按一次返回退出程序", Toast.LENGTH_SHORT).show();
                return true;
            }
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    protected int getBasicContentLayout() {
        return R.layout.activity_main;
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(!changeTheme) {
            this.finish();
            System.exit(0);
        }
    }
}