如何在导航活动中隐藏蓝色标题栏？

Question

如何隐藏像这样的导航活动蓝色标题栏：

只显示thry线！

在MainActivity：

package com.example.jehat_pc.ridapk; 


import android.content.Intent; 
import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.NavigationView; 
import android.support.design.widget.Snackbar; 
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.Gravity; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.Button; 
import android.widget.Toast; 

public class MainActivity extends AppCompatActivity 
     implements NavigationView.OnNavigationItemSelectedListener { 
    public Button bt1; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     // this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
     setContentView(R.layout.activity_main); 

     wcv(); 

     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(); 
      } 
     }); 

     bt1 = (Button) findViewById(R.id.button1); 
     bt1.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent myIntent = new Intent(MainActivity.this, ScrollingActivity.class); 
       startActivity(myIntent); 
      } 
     }); 


     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 = (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.nav_camera) { 
      // Handle the camera action 
     } else if (id == R.id.nav_gallery) { 

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

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

    public void wcv() 
    { 
     LayoutInflater myft=getLayoutInflater(); 
     View myview=myft.inflate(R.layout.welcom, (ViewGroup) findViewById(R.id.llay)); 

     Toast toast = new Toast(getApplicationContext()); 
     toast.setGravity(Gravity.FILL, 0, 0); 
     toast.setDuration(Toast.LENGTH_LONG); 
     toast.setView(myview); 
     toast.show(); 
    } 
} 

和content_main代码：

，内容主要活动：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/content_main" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="com.example.jehat_pc.ridapk.MainActivity" 
    tools:showIn="@layout/app_bar_main" 
    android:background="@drawable/home"> 

<LinearLayout android:id="@+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="fill_parent" 
     android:orientation="horizontal"> 
    </LinearLayout> 



</RelativeLayout> 

和activity_main：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/drawer_layout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:fitsSystemWindows="true" 
    tools:openDrawer="start"> 

    <include 
     layout="@layout/app_bar_main" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 

    <android.support.design.widget.NavigationView 
     android:id="@+id/nav_view" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:layout_gravity="start" 
     android:fitsSystemWindows="true" 
     app:headerLayout="@layout/nav_header_main" 
     app:menu="@menu/activity_main_drawer" /> 

</android.support.v4.widget.DrawerLayout> 

谢谢... ..

Answer 1

通过隐藏，你的意思是透明吗？

如果是这样尝试toolbar.getBackgroundColor().setAlpha(0);