导航抽屉 ListView 为空
Navigation Drawer ListView is empty
我有一个应用程序，第一个 activity 是登录页面。当用户成功登录时，他会看到他的项目。我正在使用 ListFragment 显示此列表（因为我还有 public 用户在登录页面的一半中看到的项目）。在他登录后，我在 activity 中添加了一个抽屉式导航。在经历了很多混乱之后，我能够在 activity 上添加抽屉式导航，但是它有一个空列表。
DrawerActivity.java:
public class DrawerActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mScreenTitles;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.private_project_list);
mTitle = mDrawerTitle = getTitle();
mScreenTitles = getResources().getStringArray(R.array.screen_titles);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mScreenTitles));
//mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_navigation_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
}
}
PrivateProjectListActivity.java:（扩展了 DrawerActivity）
public class PrivateProjectListActivity extends DrawerActivity {
private final static String TAG_TITLE = "title";
private final static String TAG_ANIM_ARRAY_ID = "animation_array";
private final static String TAG_PROJECTS = "projects";
private final static String TAG_ID = "id";
JSONArray projects = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.private_project_list);
new HttpGetHandler().execute();
}
private class HttpGetHandler extends AsyncTask<String, Void, Void> {
@Override
protected Void doInBackground(String... params) {
String jsonUrl = "http://canvasflip.com/protected/actions/user.php?action=get-projects&network=Escort&index=0&count=100";
HttpGet httpGet = new HttpGet(jsonUrl);
try {
HttpResponse httpResponse = MainActivity.httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
InputStream content = httpEntity.getContent();
String result = convertToString(content);
JSONObject jsonObject = new JSONObject(result);
projects = jsonObject.getJSONArray(TAG_PROJECTS);
PrivateProjectListActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
try{
ArrayList<String> projectTitle = new ArrayList<String>();
ArrayList<String> imageId = new ArrayList<String>();
ArrayList<String> playId = new ArrayList<String>();
for(int i=0; i<projects.length(); i++) {
JSONObject p = projects.getJSONObject(i);
String title = p.getString(TAG_TITLE);
String id = p.getString(TAG_ID);
String array_anim_id = p.getString(TAG_ANIM_ARRAY_ID);
String imgId = array_anim_id.substring(0, 4);
projectTitle.add(title);
imageId.add(imgId);
playId.add(id);
}
String[] arrProjectTitle = new String[projectTitle.size()];
String[] arrImageId = new String[imageId.size()];
final String[] pid = new String[playId.size()];
for(int i = 0; i<projectTitle.size(); i++)
arrProjectTitle[i] = projectTitle.get(i);
for(int j = 0; j<imageId.size(); j++)
arrImageId[j] = imageId.get(j);
for(int k = 0; k<playId.size(); k++)
pid[k] = playId.get(k);
Bundle b = new Bundle();
b.putStringArray("projectTitle", arrProjectTitle);
b.putStringArray("imageId", arrImageId);
PrivateProjectsListFragment fragment = new PrivateProjectsListFragment();
fragment.setArguments(b);
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.privateProjectsContainer,fragment);
ft.commit();
}catch(Exception e) {
}
}
});
}catch(Exception e) {
}
return null;
}
public String convertToString(InputStream inputStream) throws IOException {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine())!=null) {
result += line;
}
inputStream.close();
return result;
}
}
}
private_project_list.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="@+id/drawer_layout"
xmlns:android="http://schemas.android.com/apk/res/android">
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:id="@+id/privateProjectsContainer"
android:background="#eeeeee">
</FrameLayout>
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
另外，切换按钮也不起作用。我只看到一个后退箭头，点击它没有任何反应，我必须从左边滑动才能打开抽屉。
我建议您按照以下方式进行操作：
在DrawerActivity中只创建导航抽屉，不使用onCreate()，而是使用onStart()。 onCreate() 将在扩展 DrawerActivity 的 activity 中调用，您将在那里调用 setContentView
您的 class 将如下所示：
public class DrawerActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mScreenTitles;
@Override
protected void onStart(){
super.onStart();
mTitle = mDrawerTitle = getTitle();
mScreenTitles = getResources().getStringArray(R.array.screen_titles);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mScreenTitles));
//mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_navigation_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
}
}
在每个 activity 中，您想要在其中使用 Drawer，您必须像当前 private_project_list.xml 一样构建布局，使用 DrawerLayout 作为主要容器，doby 布局您的 activity 作为第一个 child，导航抽屉布局作为第二个 child。然后，将 activity 扩展为 DrawerActivity.
Antoher 的建议是获取 DrawerActivity 中的列表，在其中调用 HttpGetHandler()，只有当数组已满时才必须设置适配器，否则传递给适配器一个空数组，因此列表将为空。
关于菜单按钮不显示
在 DrawerActivity 中似乎缺少一些操作栏的方法，尝试添加以下内容
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
我有一个应用程序，第一个 activity 是登录页面。当用户成功登录时，他会看到他的项目。我正在使用 ListFragment 显示此列表（因为我还有 public 用户在登录页面的一半中看到的项目）。在他登录后，我在 activity 中添加了一个抽屉式导航。在经历了很多混乱之后，我能够在 activity 上添加抽屉式导航，但是它有一个空列表。
DrawerActivity.java:
public class DrawerActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mScreenTitles;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.private_project_list);
mTitle = mDrawerTitle = getTitle();
mScreenTitles = getResources().getStringArray(R.array.screen_titles);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mScreenTitles));
//mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_navigation_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
}
}
PrivateProjectListActivity.java:（扩展了 DrawerActivity）
public class PrivateProjectListActivity extends DrawerActivity {
private final static String TAG_TITLE = "title";
private final static String TAG_ANIM_ARRAY_ID = "animation_array";
private final static String TAG_PROJECTS = "projects";
private final static String TAG_ID = "id";
JSONArray projects = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.private_project_list);
new HttpGetHandler().execute();
}
private class HttpGetHandler extends AsyncTask<String, Void, Void> {
@Override
protected Void doInBackground(String... params) {
String jsonUrl = "http://canvasflip.com/protected/actions/user.php?action=get-projects&network=Escort&index=0&count=100";
HttpGet httpGet = new HttpGet(jsonUrl);
try {
HttpResponse httpResponse = MainActivity.httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
InputStream content = httpEntity.getContent();
String result = convertToString(content);
JSONObject jsonObject = new JSONObject(result);
projects = jsonObject.getJSONArray(TAG_PROJECTS);
PrivateProjectListActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
try{
ArrayList<String> projectTitle = new ArrayList<String>();
ArrayList<String> imageId = new ArrayList<String>();
ArrayList<String> playId = new ArrayList<String>();
for(int i=0; i<projects.length(); i++) {
JSONObject p = projects.getJSONObject(i);
String title = p.getString(TAG_TITLE);
String id = p.getString(TAG_ID);
String array_anim_id = p.getString(TAG_ANIM_ARRAY_ID);
String imgId = array_anim_id.substring(0, 4);
projectTitle.add(title);
imageId.add(imgId);
playId.add(id);
}
String[] arrProjectTitle = new String[projectTitle.size()];
String[] arrImageId = new String[imageId.size()];
final String[] pid = new String[playId.size()];
for(int i = 0; i<projectTitle.size(); i++)
arrProjectTitle[i] = projectTitle.get(i);
for(int j = 0; j<imageId.size(); j++)
arrImageId[j] = imageId.get(j);
for(int k = 0; k<playId.size(); k++)
pid[k] = playId.get(k);
Bundle b = new Bundle();
b.putStringArray("projectTitle", arrProjectTitle);
b.putStringArray("imageId", arrImageId);
PrivateProjectsListFragment fragment = new PrivateProjectsListFragment();
fragment.setArguments(b);
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.privateProjectsContainer,fragment);
ft.commit();
}catch(Exception e) {
}
}
});
}catch(Exception e) {
}
return null;
}
public String convertToString(InputStream inputStream) throws IOException {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine())!=null) {
result += line;
}
inputStream.close();
return result;
}
}
}
private_project_list.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="@+id/drawer_layout"
xmlns:android="http://schemas.android.com/apk/res/android">
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:id="@+id/privateProjectsContainer"
android:background="#eeeeee">
</FrameLayout>
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
另外，切换按钮也不起作用。我只看到一个后退箭头，点击它没有任何反应，我必须从左边滑动才能打开抽屉。
我建议您按照以下方式进行操作：
在DrawerActivity中只创建导航抽屉，不使用onCreate()，而是使用onStart()。 onCreate() 将在扩展 DrawerActivity 的 activity 中调用，您将在那里调用 setContentView
您的 class 将如下所示：
public class DrawerActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mScreenTitles;
@Override
protected void onStart(){
super.onStart();
mTitle = mDrawerTitle = getTitle();
mScreenTitles = getResources().getStringArray(R.array.screen_titles);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mScreenTitles));
//mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_navigation_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
}
}
在每个 activity 中，您想要在其中使用 Drawer，您必须像当前 private_project_list.xml 一样构建布局，使用 DrawerLayout 作为主要容器，doby 布局您的 activity 作为第一个 child，导航抽屉布局作为第二个 child。然后，将 activity 扩展为 DrawerActivity.
Antoher 的建议是获取 DrawerActivity 中的列表，在其中调用 HttpGetHandler()，只有当数组已满时才必须设置适配器，否则传递给适配器一个空数组，因此列表将为空。
关于菜单按钮不显示
在 DrawerActivity 中似乎缺少一些操作栏的方法，尝试添加以下内容
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}