怎么解决？点击按钮后我的应用程序关闭了力量

Question

    public class Navigationmenu extends AppCompatActivity {
      private DrawerLayout mDrawerLayout;
        private ActionBarDrawerToggle mToggle;
        private Toolbar mToolbar;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_navigationmenu);

            mDrawerLayout = (DrawerLayout)findViewById(R.id.drawerLayout);
            mToggle = new ActionBarDrawerToggle(this,mDrawerLayout,R.string.Open,R.string.Close );

            mToolbar = (Toolbar)findViewById(R.id.nav_action);
            setSupportActionBar(mToolbar);

            mDrawerLayout.addDrawerListener(mToggle);
            mToggle.syncState();

            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }



        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            if(mToggle.onOptionsItemSelected(item))
            {
                return true;
            }
            return super.onOptionsItemSelected(item);
        }
    }

错误。

我该如何解决？当我点击按钮时，我的应用程序被迫关闭。有人可以帮我吗？

错误显示在“super.onCreate(savedInstanceState);”我不知道如何修复它。

Answer 1

我不确定你的照片，但似乎你正试图在你的项目中添加一个导航抽屉。您不能在预先存在的代码之上添加导航抽屉，而是以这种方式执行它会更麻烦。

为了使导航抽屉正常工作，您必须添加一些其他代码而不是Android Studio提供的代码。如果要添加导航抽屉而不是需要将代码添加到MainActivity.java而不是其自己的文件，那么您可以在每个其他片段类中实现该导航抽屉以使导航抽屉工作。

您可能尝试添加的内容类似于

public class Navigationmenu extends AppCompatActivity {
   //Try this piece here
    NavigationView navigationView = null;
    private DrawerLayout mDrawerLayout;
    private ActionBarDrawerToggle mToggle;
    private Toolbar mToolbar;

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

        mDrawerLayout = (DrawerLayout)findViewById(R.id.drawerLayout);
        mToggle = new  ActionBarDrawerToggle(this,mDrawerLayout,R.string.Open,R.string.Close );

        mToolbar = (Toolbar)findViewById(R.id.nav_action);
        setSupportActionBar(mToolbar);

        mDrawerLayout.addDrawerListener(mToggle);
        mToggle.syncState();


        //Try adding this to the code
        navigationView = (NavigationView) findViewById(R.id.nav_view); //Declared in activity_main.xml
        navigationView.setNavigationItemSelectedListener(this);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }



    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(mToggle.onOptionsItemSelected(item))
        {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

如果您正在尝试使用片段制作导航抽屉，请查看我制作的完整MainActivity.java，并注意导航抽屉中的所有内容都在片段上运行。

import android.net.Uri;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener, MainFragment.OnFragmentInteractionListener, LoginFragment.OnFragmentInteractionListener {



    NavigationView navigationView = null;
    Toolbar toolbar = null;

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


        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        MainFragment fragment = new MainFragment();

        android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();

        fragmentTransaction.replace(R.id.fragment_container, fragment);
        fragmentTransaction.commit();



        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.main) {
            MainFragment fragment = new MainFragment();
            android.support.v4.app.FragmentTransaction fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();

        } else if (id == R.id.login) {
            LoginFragment fragment = new LoginFragment();
            android.support.v4.app.FragmentTransaction fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    @Override
    public void onFragmentInteraction(Uri uri) {
        //Leave blank
    }
}