安卓 : Using NavigationView as a BaseActivity

Question

我正在设计支持库，我希望“在不同的 Activity 中使用相同的抽屉导航”。我尝试使用以下代码扩展 MainActivity，但不起作用。

MainActivity.java

public class MainActivity extends AppCompatActivity{

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mDrawer = (NavigationView) findViewById(R.id.main_drawer);
    mDrawer.setNavigationItemSelectedListener(this);
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);  
    mDrawerLayout.setDrawerListener(mDrawerToggle);

}
private void navigate(int mSelectedId) {
    Intent intent = null;
    if (mSelectedId == R.id.navigation_item_2) {
        mDrawerLayout.closeDrawer(GravityCompat.START);
        intent = new Intent(this, SampleActivity.class);
        startActivity(intent);
    }

}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    mDrawerToggle.onConfigurationChanged(newConfig);
}
}

SampleActivity.java

public class SecondActivity extends MainActivity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_second, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
}

activity_main.xml

<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"
tools:context=".MainActivity">

<LinearLayout
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimary"
        android:minHeight="?attr/actionBarSize"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
</LinearLayout>

<android.support.design.widget.NavigationView
    android:id="@+id/main_drawer"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    app:headerLayout="@layout/drawer_header"
    app:itemIconTint="@color/colorAccent"
    app:itemTextColor="@color/colorTextSecondary"
    app:menu="@menu/menu_drawer" />

Answer 1

它不会工作，因为在 SampleActivity 中，您通过调用以下内容覆盖了内容 View :

setContentView(R.layout.activity_second);

通过调用它，您的 SampleActivity 将无法访问 NavigationView，因为 setContentView() 更改了 布局而不是将其膨胀到 MainActivity 的布局中。

解决方法是提供一个专用位置(如 FrameLayout)，然后将任何子类的布局扩展到它。

// Add these codes below the toolbar in your activity_main.xml

<FrameLayout
    android:id="@+id/ly_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

并且在扩展类时，调用它而不是 setContentView():

getLayoutInflater().inflate(R.layout.activity_second, findViewById(R.id.ly_content));