SupportManager.getFragmentById returns 空
SupportManager.getFragmentById returns null
大家好,我一直被 id 返回 null 的 getFragment 困住了
xml 文件
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
</FrameLayout>
<fragment
android:id="@+id/navigation_drawer"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="left"
tools:layout="@layout/fragment_navigation_drawer_list" />
</android.support.v4.widget.DrawerLayout>
MainActivity.java
public class MainActivity extends ActionBarActivity {
private static final String SCREEN_NAME = "MainActivity";
@Optional @InjectView(R.id.tool_bar) Toolbar toolbar;
//@InjectView(R.id.DrawerLayout) DrawerLayout mDrawerLayout;
@Inject GamerzWikiApplication mGamerzWikiApplication;
private NavigationDrawerFragment mNavigationDrawerFragment;
android.support.v7.app.ActionBar mActionBar;
ActionBarDrawerToggle mDrawerToggable;
private ArrayList<NavigationDrawerItem> mNavigationDrawerItemList;
private DrawerLayout mDrawerLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.inject(this);
ObjectGraphInjector.inject(this);
setSupportActionBar(toolbar);
setupActionBar();
setupDrawerLayout();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
private void setupActionBar() {
mActionBar = getSupportActionBar();
//SetDisplayHomeAsUpEnabled => Set whether home should be displayed as an "up" affordance(objects action/ to perform).
//mActionBar.setDisplayHomeAsUpEnabled(true);
//Enable or disable the "home" button in the corner of the action bar.
mActionBar.setHomeButtonEnabled(true);
}
private void setupDrawerLayout() {
mNavigationDrawerItemList = new ArrayList<NavigationDrawerItem>();
mNavigationDrawerItemList.add(new NavigationDrawerItem(getString(R.string.title_home), "{fa-home}") {
@Override
public void onClick() {
mActionBar.setTitle(R.string.title_home);
/*
getSupportFragmentManager().beginTransaction()
.replace(R.id.container, new TopGameFragment())
.commit();
*/
}
});
mNavigationDrawerItemList.add(new NavigationDrawerItem("ユーザ情報の確認・表示", "{fa-user}") {
@Override
public void onClick() {
//startActivity(AccountSettingActivity.createIntent(getApplicationContext()));
}
});
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mNavigationDrawerFragment.setup(
R.id.navigation_drawer,
mNavigationDrawerItemList,
mDrawerLayout
);
mActionBar.setTitle(R.string.title_home);
/*
getSupportFragmentManager().beginTransaction()
.replace(R.id.container, new TopGameFragment())
.commit();*/
}
@Override
public void onAttachFragment(Fragment fragment) {
// TODO Auto-generated method stub
super.onAttachFragment(fragment);
Toast.makeText(getApplicationContext(), String.valueOf(fragment.getId()), Toast.LENGTH_SHORT).show();
}
@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);
}
}
这是logcat中抛出的异常,它指的是mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
Caused by: java.lang.NullPointerException
at com.atfreaks.gamerzwiki.MainActivity.setupDrawerLayout(MainActivity.java:101)
at com.atfreaks.gamerzwiki.MainActivity.onCreate(MainActivity.java:54)
我不知道为什么 returns null 。谁能知道为什么会这样?谢谢!我包括了整个 mainActivity.java
我觉得可能是选角错误的问题。您搜索 (NavigationDrawerFragment)
而实际片段只是一个片段。
尝试将您的 XML 片段切换为 NavigationDrawerFragment 的适当名称。
甚至尝试在 oncreate() 上手动添加它。
</android.support.v4.widget.DrawerLayout>
在你的 xml
末尾
我解决了我的问题。对于那些将来会遇到同样问题的人来说,这里就是解决方案。
问题不是因为 xml 文件或 getSupportManager.findFragmentById()
方法。通过一些调试,我尝试放置 if else 并检查 if getSupportFragment is != null
.
这是解决方法。
if(getSupportFragmentManager() != null){
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mNavigationDrawerFragment.setup(
R.id.navigation_drawer,
mNavigationDrawerItemList,
mDrawerLayout
);
} else {
Toast.makeText(getApplicationContext(), "getSupportFragmentManager is null", Toast.LENGTH_SHORT).show();
}
感谢@njzk2。
大家好,我一直被 id 返回 null 的 getFragment 困住了
xml 文件
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
</FrameLayout>
<fragment
android:id="@+id/navigation_drawer"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="left"
tools:layout="@layout/fragment_navigation_drawer_list" />
</android.support.v4.widget.DrawerLayout>
MainActivity.java
public class MainActivity extends ActionBarActivity {
private static final String SCREEN_NAME = "MainActivity";
@Optional @InjectView(R.id.tool_bar) Toolbar toolbar;
//@InjectView(R.id.DrawerLayout) DrawerLayout mDrawerLayout;
@Inject GamerzWikiApplication mGamerzWikiApplication;
private NavigationDrawerFragment mNavigationDrawerFragment;
android.support.v7.app.ActionBar mActionBar;
ActionBarDrawerToggle mDrawerToggable;
private ArrayList<NavigationDrawerItem> mNavigationDrawerItemList;
private DrawerLayout mDrawerLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.inject(this);
ObjectGraphInjector.inject(this);
setSupportActionBar(toolbar);
setupActionBar();
setupDrawerLayout();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
private void setupActionBar() {
mActionBar = getSupportActionBar();
//SetDisplayHomeAsUpEnabled => Set whether home should be displayed as an "up" affordance(objects action/ to perform).
//mActionBar.setDisplayHomeAsUpEnabled(true);
//Enable or disable the "home" button in the corner of the action bar.
mActionBar.setHomeButtonEnabled(true);
}
private void setupDrawerLayout() {
mNavigationDrawerItemList = new ArrayList<NavigationDrawerItem>();
mNavigationDrawerItemList.add(new NavigationDrawerItem(getString(R.string.title_home), "{fa-home}") {
@Override
public void onClick() {
mActionBar.setTitle(R.string.title_home);
/*
getSupportFragmentManager().beginTransaction()
.replace(R.id.container, new TopGameFragment())
.commit();
*/
}
});
mNavigationDrawerItemList.add(new NavigationDrawerItem("ユーザ情報の確認・表示", "{fa-user}") {
@Override
public void onClick() {
//startActivity(AccountSettingActivity.createIntent(getApplicationContext()));
}
});
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mNavigationDrawerFragment.setup(
R.id.navigation_drawer,
mNavigationDrawerItemList,
mDrawerLayout
);
mActionBar.setTitle(R.string.title_home);
/*
getSupportFragmentManager().beginTransaction()
.replace(R.id.container, new TopGameFragment())
.commit();*/
}
@Override
public void onAttachFragment(Fragment fragment) {
// TODO Auto-generated method stub
super.onAttachFragment(fragment);
Toast.makeText(getApplicationContext(), String.valueOf(fragment.getId()), Toast.LENGTH_SHORT).show();
}
@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);
}
}
这是logcat中抛出的异常,它指的是mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
Caused by: java.lang.NullPointerException
at com.atfreaks.gamerzwiki.MainActivity.setupDrawerLayout(MainActivity.java:101)
at com.atfreaks.gamerzwiki.MainActivity.onCreate(MainActivity.java:54)
我不知道为什么 returns null 。谁能知道为什么会这样?谢谢!我包括了整个 mainActivity.java
我觉得可能是选角错误的问题。您搜索 (NavigationDrawerFragment)
而实际片段只是一个片段。
尝试将您的 XML 片段切换为 NavigationDrawerFragment 的适当名称。
甚至尝试在 oncreate() 上手动添加它。
</android.support.v4.widget.DrawerLayout>
在你的 xml
末尾
我解决了我的问题。对于那些将来会遇到同样问题的人来说,这里就是解决方案。
问题不是因为 xml 文件或 getSupportManager.findFragmentById()
方法。通过一些调试,我尝试放置 if else 并检查 if getSupportFragment is != null
.
这是解决方法。
if(getSupportFragmentManager() != null){
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mNavigationDrawerFragment.setup(
R.id.navigation_drawer,
mNavigationDrawerItemList,
mDrawerLayout
);
} else {
Toast.makeText(getApplicationContext(), "getSupportFragmentManager is null", Toast.LENGTH_SHORT).show();
}
感谢@njzk2。