单击导航抽屉的列表项时如何打开另一个活动类？

Question

我是android的初学者。 我想打开导航抽屉列表项的另一个活动类NewTest.class onclick。但是我在/com.navigation E / MainActivity：创建片段时出错。 请告诉我这怎么了？ 谢谢。 这是我的MainActivity.class代码

public class MainActivity extends AppCompatActivity {

    private String[] mNavigationDrawerItemTitles;
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    Toolbar toolbar;
    private CharSequence mDrawerTitle;
    private CharSequence mTitle;
    android.support.v7.app.ActionBarDrawerToggle mDrawerToggle;


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

        mTitle = mDrawerTitle = getTitle();
        mNavigationDrawerItemTitles = getResources().getStringArray(R.array.navigation_drawer_items_array);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.left_drawer);

        setupToolbar();

        DataModel[] drawerItem = new DataModel[3];

        drawerItem[0] = new DataModel(R.drawable.connect, "Connect");
        drawerItem[1] = new DataModel(R.drawable.connect, "Fixtures");

        getSupportActionBar().setDisplayHomeAsUpEnabled(false);
        getSupportActionBar().setHomeButtonEnabled(true);

        DrawerItemCustomAdapter adapter = new DrawerItemCustomAdapter(this, R.layout.list_view_item_row, drawerItem);
        mDrawerList.setAdapter(adapter);
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerLayout.setDrawerListener(mDrawerToggle);
        setupDrawerToggle();

    }

    private class DrawerItemClickListener implements ListView.OnItemClickListener {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            selectItem(position);
        }

    }

    private void selectItem(int position) {

        ConnectFragment fragment = null;
        switch (position) {

            case 0:
                fragment = new ConnectFragment();
                break;

            case 1:
                Intent a = new Intent(MainActivity.this, NewTest.class);
                startActivity(a);
                break;

            default:
                break;

        }
        Toast.makeText(this, "Selected Item Position::" + position, Toast.LENGTH_LONG).show();

        if (fragment != null) {
            FragmentManager fragmentManager = getSupportFragmentManager();
            int commit = fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();

            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(mNavigationDrawerItemTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);

        } else {
            Log.e("MainActivity", "Error in creating fragment");
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getSupportActionBar().setTitle(mTitle);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mDrawerToggle.syncState();
    }

    void setupToolbar() {
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
    }

    void setupDrawerToggle() {
        mDrawerToggle = new android.support.v7.app.ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.app_name, R.string.app_name);
        //This is necessary to change the icon of the Drawer Toggle upon state change.
        mDrawerToggle.syncState();
    }
}

Answer 1

您可以为此使用onNavigationItemSelected（）方法。

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

    if (id == R.id.idofYourNavmenu)
    {
        Intent intent = new Intent(CurrentActivity.this, ActivityToCall.class);
        startActivity(intent);
    }

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

Answer 2

您可以实现如下所示：

  Fragment fragment = null;
    Class fragmentClass = null;
    if (id == R.id.nav_1) {
        fragmentClass = demo1.class;

    } else if (id == R.id.nav_2) {
//pass Activity class where you want to navigate

        fragmentClass=CredentialActivity.class;
    } 

 try {
        if(fragmentClass.newInstance() instanceof Fragment) {
            fragment = (Fragment) fragmentClass.newInstance();

            if (fragmentClass.getSimpleName().equals("DailyReport")) {
                Bundle bundle = new Bundle();

                // Insert the fragment by replacing any existing fragment
                FragmentManager fragmentManager = getSupportFragmentManager();

                fragmentManager.beginTransaction().replace(R.id.home_layout, fragment).commit();
                // Highlight the selected item has been done by NavigationView
                item.setChecked(true);
                // Set action bar title
                setTitle(item.getTitle());
                // Close the navigation drawer
                drawer.closeDrawers();
            }
        }else
        {
            // After logout redirect user to Loing Activity
            Intent i = new Intent(HomeActivity.this, fragmentClass);
            // Closing all the Activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

            // Add new Flag to start new Activity
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            // Start Login Activity
            startActivity(i);

            finish();
        }