android - 单击ImageView时如何打开Sliding Navigation Drawer？

Question

我正在尝试在我的仪表板 Activity 上实现 Navigation Drawer Activity。在我的应用程序中，我创建了一个主题，其中删除了“Toolbar/ActionBar”，只是在 custom layout 上为我的汉堡菜单放置了一个 ImageView 并将其包含在我的仪表板布局。我想要的是，当单击此 ImageView 时，将显示滑动抽屉。

我尝试做的是通过 com.project.projectname -> New -> activity -> 'Navigation Drawer Activity' 添加一个 Navigation Drawer Activity 并自动添加 NavigationActivity 类， Activity 导航.xml
app_bar_navigation.xml 等。

但我想知道如何打开抽屉？在我的 Dashboard Activity 中，我添加了这个

 public class DashboardActivity extends AppCompatActivity {

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

   View side_tab = findViewById(R.id.side_tab);
    expanded_menu = (ImageView) side_tab.findViewById(R.id.expanded_menu);

  expanded_menu.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v) {
            // open drawer here 
        }
    });

此外，在 NavigationActivity 中它使用 ActionBarDrawerToggle，我不能使用它，因为我没有应用 ActionBar。但是我可以使用什么替代方法呢？

这是我的 NavigationActivity

public class NavigationActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

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

    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.navigation, 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();
    Intent goToSreen;

    if (id == R.id.nav_dashboard) {
        goToSreen = new Intent(NavigationActivity.this, DashboardActivity.class);
        startActivity(goToSreen);
    } else if (id == R.id.nav_others) {

    }

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

感谢您的热心帮助。

---

更新

所以在我的仪表板 Activity 中我添加了以下内容

NavigationActivity navigationActivity;

@Override
protected void onCreate(Bundle savedInstanceState) {

 super.onCreate(savedInstanceState);
    setContentView(R.layout.dashboard);

    View side_tab = findViewById(R.id.side_tab);
    expanded_menu = (ImageView) side_tab.findViewById(R.id.expanded_menu);

 expanded_menu.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v) {
            navigationActivity = new NavigationActivity() ;
            navigationActivity.drawer.openDrawer(GravityCompat.START);
        }
    });

然后在我的导航 Activity 中添加一个全局变量

public class NavigationActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

DrawerLayout drawer;


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

    drawer = (DrawerLayout) findViewById(R.id.drawer_layout);

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

我已经设法在我的仪表板 Activity 中调用了 drawer，但是当我单击我的汉堡菜单时，滑动菜单仍然没有显示。应用程序崩溃并显示 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.widget.DrawerLayout.openDrawer(int)' on a null object reference

Answer 1

将此添加到您的 NavigationActivity

public class NavigationActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

//Add this line
    public static DrawerLayout drawer;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);

    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();
.......

接下来改变这个

expanded_menu.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v) {
                // open drawer here 
                NavigationActivity. drawer.openDrawer(GravityCompat.START);
        }
   });

试试这个，希望它能解决您的问题。