爲什麼我不能在我的導航中添加時間，當我擁有主代碼時？

Question

我做了一個單獨的演示應用程序，告訴time.I想要將它添加到導航窗口（漢堡窗口）。但是，當我把代碼在主導航欄的代碼是崩潰。

package com.example.user.navigationdrawer; 

import android.app.Fragment; 
import android.app.FragmentManager; 
import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.view.View; 
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; 
import android.widget.TextView; 

import java.text.SimpleDateFormat; 
import java.util.Calendar; 
import java.util.Date; 
import java.util.Locale; 

public class MainActivity extends AppCompatActivity 
    implements NavigationView.OnNavigationItemSelectedListener { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 

    FloatingActionButton fab = (FloatingActionButton)  findViewById(R.id.fab); 
    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
        .setAction("Action", null).show(); 
     } 
    }); 

    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(); 
    //This code 
    TextView theTime = (TextView) findViewById(R.id.theT); 
    SimpleDateFormat df = new SimpleDateFormat("EEEE, MMMM dd, yyyy", Locale.ENGLISH); 
    Date today = Calendar.getInstance().getTime(); 
    String reportDate = df.format(today); 
    theTime.setText(reportDate); 
    //This code 

    NavigationView 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 


    return super.onOptionsItemSelected(item); 
} 

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

    if (id == R.id.nav_first_layout) { 
     fragmentManager.beginTransaction() 
       .replace(R.id.content_frame 
         , new FirstFragment()) 
       .commit(); 
    } else if (id == R.id.nav_second_layout) { 
     fragmentManager.beginTransaction() 
       .replace(R.id.content_frame 
         , new SecondFragment()) 
       .commit(); 
    } else if (id == R.id.nav_third_layout) { 
     fragmentManager.beginTransaction() 
       .replace(R.id.content_frame 
         , new ThirdFragment()) 
       .commit(); 
    } else if (id == R.id.nav_share) { 

    } 

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


} 
} 

這是我的XML

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="200dp" 
android:background="@drawable/side_nav_bar" 
android:gravity="bottom" 
android:orientation="vertical" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
android:theme="@style/ThemeOverlay.AppCompat.Dark"> 


<ImageView 
    android:id="@+id/imageView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:adjustViewBounds="true" 
    android:layout_gravity="center_vertical" 
    android:src="@mipmap/sijny" 
    android:contentDescription="" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:paddingTop="7dp" 
    android:paddingBottom="2dp" 
    android:text="SIJNY Islamic Center" 
    android:textAppearance="@style/TextAppearance.AppCompat.Body1" 
    android:id="@+id/textView3" 
    android:textStyle="normal|bold" 
    android:adjustViewBounds="true" /> 

<TextView 
    android:id="@+id/theT" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:paddingBottom="2dp" 
    android:textColor="#FFFF" 
    android:text="Time" /> 

<TextView 
    android:id="@+id/textView6" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textColor="#FFFF" 
    android:text="13 Ramadan 1436" /> 


</LinearLayout> 

Answer 1

好的問題解決now.It原來我剛添加的代碼一定行，因爲我想在一個片段來修改一個TextView。

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

    View navHeaderView = navigationView.getHeaderView(0); // this 
    TextView theTime = (TextView) navHeaderView.findViewById(R.id.theT);//this 

    SimpleDateFormat df = new SimpleDateFormat("EEEE, MMMM dd, yyyy", Locale.ENGLISH); 
    Date today = Calendar.getInstance().getTime(); 
    String reportDate = df.format(today); 
    theTime.setText(reportDate); 

您的變量/ xml ID可能會有所不同。感謝您的幫助球員。