使用没有 DrawerToggle 的 DrawerLayout 和 AppCompatActivity 实现返回导航
Implement back navigation with DrawerLayout and AppCompatActivity without DrawerToggle
我一直在搜索和思考如何在使用导航抽屉时在片段之间来回切换时实现我想要的期望行为。实际上文档说：
在您的应用中使用片段时，各个 FragmentTransaction 对象可能表示应添加到后台堆栈的上下文更改。例如，如果您要通过交换片段在手机上实现 master/detail 流程，您应该确保在详细信息屏幕上按下返回按钮 returns 用户到主屏幕
所以在我的应用程序中，我有一个 MainActivity 控制所有内容和一个导航布局，您可以在预定义选项之间切换。这是您启动应用程序时的视图
当您单击导航抽屉中的项目时，它会打开一个新片段来替换 main_content，如下所示：
此时的行为是正确的，因此如果您想更改选项，您需要再次打开导航抽屉以在菜单选项之间切换。
这是主要的 Activity（注意没有抽屉开关）
MainActivity.java
public class MainActivity extends AppCompatActivity {
ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout drawerLayout;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSnackBarView = findViewById(R.id.myCoordinatorLayout);
setToolbar(); // Set Toolbar como action bar
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null) {
setupDrawerContent(navigationView);
}
drawerTitle = getResources().getString(R.string.app_name);
if (savedInstanceState == null) {
selectItem(drawerTitle, mCurrentSelectedPosition);
}
}
private void setToolbar() {
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final ActionBar ab = getSupportActionBar();
if (ab != null) {
// Poner ícono del drawer toggle
ab.setHomeAsUpIndicator(R.drawable.ic_menu);
ab.setDisplayHomeAsUpEnabled(true);
}
}
private void setupDrawerContent(final NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
// Marcar item presionado
menuItem.setChecked(true);
// Crear nuevo fragmento
String title = menuItem.getTitle().toString();
int id = menuItem.getItemId();
selectItem(title, id);
return true;
}
}
);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!drawerLayout.isDrawerOpen(GravityCompat.START)) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
drawerLayout.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
private void selectItem(String title, int id) {
Bundle args = new Bundle();
args.putString(PlaceholderFragment.ARG_SECTION_TITLE, title);
Fragment fragment = PlaceholderFragment.newInstance(title);
fragment.setArguments(args);
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
switch (id) {
case R.id.nav_localizacion:
//Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 0;
LocalizacionFragment fragment_localizacion = new LocalizacionFragment();
// fragmentManager = getSupportFragmentManager();
Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_localizacion)
.commit();
break;
case R.id.nav_productos:
Snackbar.make(mSnackBarView, R.string.menu_productos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 1;
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
break;
case R.id.nav_consejos:
Snackbar.make(mSnackBarView, R.string.menu_consejos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 3;
ConsejosFragment fragment_consejo = new ConsejosFragment();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_consejo)
.commit();
break;
default:
break;
}
drawerLayout.closeDrawers(); // Cerrar drawer
setTitle(title); // título actual
}
}
我不使用汉堡包图标，因为它隐藏在导航布局下，但事情就是这样。当您在回收视图中单击 "Recetas" 时，它会打开一个新片段（替换），但现在我想显示向上插入符号图标并为我的应用程序提供正确的返回导航。
这里是 "Consejos" 片段的代码 class
Consejos.java
public class ConsejosFragment extends Fragment {
RecyclerView mRecycler;
ConsejosAdapter mAdapter;
FragmentActivity mActivity;
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
this.mActivity = (FragmentActivity) activity;
setRetainInstance(true);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
List items = new ArrayList();
items.add(new ConsejosInfo("Recetas", R.drawable.icon_recetas));
/* Inflamos el layout */
View v = inflater.inflate(R.layout.consejos_layout_recycler, container, false);
/* Obtenemos el Recycle */
mRecycler = (RecyclerView) v.findViewById(R.id.recycler_consejos);
/* Creamos el adaptador */
mAdapter = new ConsejosAdapter(mActivity, items);
/* Set click en adapter */
return v;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mRecycler.setHasFixedSize(true);
mRecycler.setLayoutManager(new LinearLayoutManager(getActivity()));
mRecycler.setAdapter(mAdapter);
}
}
这是 Recyclerview 使用的适配器，用于处理对内部项目的点击：
Adapter.java
public class ConsejosAdapter extends RecyclerView.Adapter<ConsejosAdapter.ConsejosViewHolder> {
private List<ConsejosInfo> _items = new ArrayList<ConsejosInfo>();
private final FragmentActivity mActivity;
private Context context;
public ConsejosAdapter(FragmentActivity mActivity, List<ConsejosInfo> items) {
this._items = items;
this.mActivity = mActivity;
}
@Override
public int getItemCount() {
return _items.size();
}
@Override
public ConsejosViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.cardview_consejos, viewGroup, false);
return new ConsejosViewHolder(v);
}
@Override
public void onBindViewHolder(ConsejosViewHolder viewHolder, int position) {
viewHolder.imagen.setImageResource(_items.get(position).get_imagen());
viewHolder.nombre.setText(_items.get(position).get_nombre());
}
public class ConsejosViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageView imagen;
public TextView nombre;
public ConsejosViewHolder(final View itemView) {
super(itemView);
imagen = (ImageView) itemView.findViewById(R.id.consejos_imagen);
nombre = (TextView) itemView.findViewById(R.id.consejos_nombre);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
RecetasFragment recetasFragment = new RecetasFragment();
FragmentManager fragmentManager = mActivity.getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, recetasFragment)
.addToBackStack(null)
.commit();
}
}
}
在 Consejos 适配器中，我在调用新片段（片段内部）之前添加了片段堆栈，这改变了后退按钮的行为，所以在此之前，如果您按下后退按钮，则会关闭应用程序，但现在它将您带到 Consejos 片段，但现在我想添加向上插入符号并进行与单击后退按钮时完全相同的操作，但我不知道如何实现它。
请随时索取更多代码
非常感谢
我会给你完整的答案：
我们将使用接口与 RecetasFragment 中的 MainActivity 进行通信，以便我们可以启用和禁用导航后退按钮。
RecetasFragment class:
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by hema on 8/19/2015.
*/
public class RecetasFragment extends Fragment {
private CommunicateWithActivity mWithActivity;
public RecetasFragment() {
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mWithActivity = (CommunicateWithActivity) activity; // MainActivity must implement CommunicateWithActivity interface.
mWithActivity.enableNavigationBack(true); // We enable navigation back here.
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement CommunicateWithActivity");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_recetas, container, false);
}
@Override
public void onDestroy() {
super.onDestroy();
mWithActivity.enableNavigationBack(false); // We disable navigation back here, restore menu icon.
}
public interface CommunicateWithActivity {
void enableNavigationBack(boolean enable);// we will implement this method in MainActivity class.
}
}
而在MainActivityclass中我们会实现CommunicateWithActivity接口，修改你的MainActivityclass（只需要修改）：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class MainActivity extends AppCompatActivity implements RecetasFragment.CommunicateWithActivity {
private Toolbar mToolbar;
private DrawerLayout drawerLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
mToolbar.setNavigationIcon(R.drawable.ic_menu);
mSnackBarView = findViewById(R.id.myCoordinatorLayout);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null) {
setupDrawerContent(navigationView);
}
drawerTitle = getResources().getString(R.string.app_name);
if (savedInstanceState == null) {
selectItem(drawerTitle, mCurrentSelectedPosition);
}
}
private void setupDrawerContent(final NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
// Marcar item presionado
menuItem.setChecked(true);
// Crear nuevo fragmento
String title = menuItem.getTitle().toString();
int id = menuItem.getItemId();
selectItem(title, id);
return true;
}
}
);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!drawerLayout.isDrawerOpen(GravityCompat.START)) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
drawerLayout.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
private void selectItem(String title, int id) {
Bundle args = new Bundle();
args.putString(PlaceholderFragment.ARG_SECTION_TITLE, title);
Fragment fragment = PlaceholderFragment.newInstance(title);
fragment.setArguments(args);
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
switch (id) {
case R.id.nav_localizacion:
//Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 0;
LocalizacionFragment fragment_localizacion = new LocalizacionFragment();
// fragmentManager = getSupportFragmentManager();
Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_localizacion)
.commit();
break;
case R.id.nav_productos:
Snackbar.make(mSnackBarView, R.string.menu_productos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 1;
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
break;
case R.id.nav_consejos:
Snackbar.make(mSnackBarView, R.string.menu_consejos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 3;
ConsejosFragment fragment_consejo = new ConsejosFragment();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_consejo)
.commit();
break;
default:
break;
}
drawerLayout.closeDrawers(); // Cerrar drawer
setTitle(title); // título actual
}
@Override
public void enableNavigationBack(boolean enable) {
if(enable) {
// We enable the navigation back button here
mToolbar.setNavigationIcon(R.drawable.abc_ic_ab_back_mtrl_am_alpha);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// On navigation back button clicked.
if(getSupportFragmentManager().getBackStackEntryCount() > 0) { // Check if there is fragments in BackStack.
getSupportFragmentManager().popBackStack(); // PopBackStack.
} else {
// You can implement this part as you want.
return;
}
}
});
} else {
mToolbar.setNavigationIcon(R.drawable.ic_menu);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(drawerLayout != null) {
drawerLayout.openDrawer(Gravity.LEFT);
}
}
});
}
}
}
有什么不明白的地方请告诉我。
我一直在搜索和思考如何在使用导航抽屉时在片段之间来回切换时实现我想要的期望行为。实际上文档说： 在您的应用中使用片段时，各个 FragmentTransaction 对象可能表示应添加到后台堆栈的上下文更改。例如，如果您要通过交换片段在手机上实现 master/detail 流程，您应该确保在详细信息屏幕上按下返回按钮 returns 用户到主屏幕
所以在我的应用程序中，我有一个 MainActivity 控制所有内容和一个导航布局，您可以在预定义选项之间切换。这是您启动应用程序时的视图
当您单击导航抽屉中的项目时，它会打开一个新片段来替换 main_content，如下所示：
此时的行为是正确的，因此如果您想更改选项，您需要再次打开导航抽屉以在菜单选项之间切换。
这是主要的 Activity（注意没有抽屉开关）
MainActivity.java
public class MainActivity extends AppCompatActivity {
ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout drawerLayout;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSnackBarView = findViewById(R.id.myCoordinatorLayout);
setToolbar(); // Set Toolbar como action bar
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null) {
setupDrawerContent(navigationView);
}
drawerTitle = getResources().getString(R.string.app_name);
if (savedInstanceState == null) {
selectItem(drawerTitle, mCurrentSelectedPosition);
}
}
private void setToolbar() {
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final ActionBar ab = getSupportActionBar();
if (ab != null) {
// Poner ícono del drawer toggle
ab.setHomeAsUpIndicator(R.drawable.ic_menu);
ab.setDisplayHomeAsUpEnabled(true);
}
}
private void setupDrawerContent(final NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
// Marcar item presionado
menuItem.setChecked(true);
// Crear nuevo fragmento
String title = menuItem.getTitle().toString();
int id = menuItem.getItemId();
selectItem(title, id);
return true;
}
}
);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!drawerLayout.isDrawerOpen(GravityCompat.START)) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
drawerLayout.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
private void selectItem(String title, int id) {
Bundle args = new Bundle();
args.putString(PlaceholderFragment.ARG_SECTION_TITLE, title);
Fragment fragment = PlaceholderFragment.newInstance(title);
fragment.setArguments(args);
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
switch (id) {
case R.id.nav_localizacion:
//Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 0;
LocalizacionFragment fragment_localizacion = new LocalizacionFragment();
// fragmentManager = getSupportFragmentManager();
Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_localizacion)
.commit();
break;
case R.id.nav_productos:
Snackbar.make(mSnackBarView, R.string.menu_productos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 1;
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
break;
case R.id.nav_consejos:
Snackbar.make(mSnackBarView, R.string.menu_consejos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 3;
ConsejosFragment fragment_consejo = new ConsejosFragment();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_consejo)
.commit();
break;
default:
break;
}
drawerLayout.closeDrawers(); // Cerrar drawer
setTitle(title); // título actual
}
}
我不使用汉堡包图标，因为它隐藏在导航布局下，但事情就是这样。当您在回收视图中单击 "Recetas" 时，它会打开一个新片段（替换），但现在我想显示向上插入符号图标并为我的应用程序提供正确的返回导航。
这里是 "Consejos" 片段的代码 class
Consejos.java
public class ConsejosFragment extends Fragment {
RecyclerView mRecycler;
ConsejosAdapter mAdapter;
FragmentActivity mActivity;
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
this.mActivity = (FragmentActivity) activity;
setRetainInstance(true);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
List items = new ArrayList();
items.add(new ConsejosInfo("Recetas", R.drawable.icon_recetas));
/* Inflamos el layout */
View v = inflater.inflate(R.layout.consejos_layout_recycler, container, false);
/* Obtenemos el Recycle */
mRecycler = (RecyclerView) v.findViewById(R.id.recycler_consejos);
/* Creamos el adaptador */
mAdapter = new ConsejosAdapter(mActivity, items);
/* Set click en adapter */
return v;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mRecycler.setHasFixedSize(true);
mRecycler.setLayoutManager(new LinearLayoutManager(getActivity()));
mRecycler.setAdapter(mAdapter);
}
}
这是 Recyclerview 使用的适配器，用于处理对内部项目的点击：
Adapter.java
public class ConsejosAdapter extends RecyclerView.Adapter<ConsejosAdapter.ConsejosViewHolder> {
private List<ConsejosInfo> _items = new ArrayList<ConsejosInfo>();
private final FragmentActivity mActivity;
private Context context;
public ConsejosAdapter(FragmentActivity mActivity, List<ConsejosInfo> items) {
this._items = items;
this.mActivity = mActivity;
}
@Override
public int getItemCount() {
return _items.size();
}
@Override
public ConsejosViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.cardview_consejos, viewGroup, false);
return new ConsejosViewHolder(v);
}
@Override
public void onBindViewHolder(ConsejosViewHolder viewHolder, int position) {
viewHolder.imagen.setImageResource(_items.get(position).get_imagen());
viewHolder.nombre.setText(_items.get(position).get_nombre());
}
public class ConsejosViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageView imagen;
public TextView nombre;
public ConsejosViewHolder(final View itemView) {
super(itemView);
imagen = (ImageView) itemView.findViewById(R.id.consejos_imagen);
nombre = (TextView) itemView.findViewById(R.id.consejos_nombre);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
RecetasFragment recetasFragment = new RecetasFragment();
FragmentManager fragmentManager = mActivity.getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, recetasFragment)
.addToBackStack(null)
.commit();
}
}
}
在 Consejos 适配器中，我在调用新片段（片段内部）之前添加了片段堆栈，这改变了后退按钮的行为，所以在此之前，如果您按下后退按钮，则会关闭应用程序，但现在它将您带到 Consejos 片段，但现在我想添加向上插入符号并进行与单击后退按钮时完全相同的操作，但我不知道如何实现它。
请随时索取更多代码
非常感谢
我会给你完整的答案：
我们将使用接口与 RecetasFragment 中的 MainActivity 进行通信，以便我们可以启用和禁用导航后退按钮。
RecetasFragment class:
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by hema on 8/19/2015.
*/
public class RecetasFragment extends Fragment {
private CommunicateWithActivity mWithActivity;
public RecetasFragment() {
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mWithActivity = (CommunicateWithActivity) activity; // MainActivity must implement CommunicateWithActivity interface.
mWithActivity.enableNavigationBack(true); // We enable navigation back here.
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement CommunicateWithActivity");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_recetas, container, false);
}
@Override
public void onDestroy() {
super.onDestroy();
mWithActivity.enableNavigationBack(false); // We disable navigation back here, restore menu icon.
}
public interface CommunicateWithActivity {
void enableNavigationBack(boolean enable);// we will implement this method in MainActivity class.
}
}
而在MainActivityclass中我们会实现CommunicateWithActivity接口，修改你的MainActivityclass（只需要修改）：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class MainActivity extends AppCompatActivity implements RecetasFragment.CommunicateWithActivity {
private Toolbar mToolbar;
private DrawerLayout drawerLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
mToolbar.setNavigationIcon(R.drawable.ic_menu);
mSnackBarView = findViewById(R.id.myCoordinatorLayout);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null) {
setupDrawerContent(navigationView);
}
drawerTitle = getResources().getString(R.string.app_name);
if (savedInstanceState == null) {
selectItem(drawerTitle, mCurrentSelectedPosition);
}
}
private void setupDrawerContent(final NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
// Marcar item presionado
menuItem.setChecked(true);
// Crear nuevo fragmento
String title = menuItem.getTitle().toString();
int id = menuItem.getItemId();
selectItem(title, id);
return true;
}
}
);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!drawerLayout.isDrawerOpen(GravityCompat.START)) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
drawerLayout.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
private void selectItem(String title, int id) {
Bundle args = new Bundle();
args.putString(PlaceholderFragment.ARG_SECTION_TITLE, title);
Fragment fragment = PlaceholderFragment.newInstance(title);
fragment.setArguments(args);
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
switch (id) {
case R.id.nav_localizacion:
//Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 0;
LocalizacionFragment fragment_localizacion = new LocalizacionFragment();
// fragmentManager = getSupportFragmentManager();
Snackbar.make(mSnackBarView, R.string.menu_localization, Snackbar.LENGTH_SHORT).show();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_localizacion)
.commit();
break;
case R.id.nav_productos:
Snackbar.make(mSnackBarView, R.string.menu_productos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 1;
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment)
.commit();
break;
case R.id.nav_consejos:
Snackbar.make(mSnackBarView, R.string.menu_consejos, Snackbar.LENGTH_SHORT).show();
mCurrentSelectedPosition = 3;
ConsejosFragment fragment_consejo = new ConsejosFragment();
fragmentManager
.beginTransaction()
.replace(R.id.main_content, fragment_consejo)
.commit();
break;
default:
break;
}
drawerLayout.closeDrawers(); // Cerrar drawer
setTitle(title); // título actual
}
@Override
public void enableNavigationBack(boolean enable) {
if(enable) {
// We enable the navigation back button here
mToolbar.setNavigationIcon(R.drawable.abc_ic_ab_back_mtrl_am_alpha);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// On navigation back button clicked.
if(getSupportFragmentManager().getBackStackEntryCount() > 0) { // Check if there is fragments in BackStack.
getSupportFragmentManager().popBackStack(); // PopBackStack.
} else {
// You can implement this part as you want.
return;
}
}
});
} else {
mToolbar.setNavigationIcon(R.drawable.ic_menu);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(drawerLayout != null) {
drawerLayout.openDrawer(Gravity.LEFT);
}
}
});
}
}
}
有什么不明白的地方请告诉我。