我需要获取所选选项卡的数字位置,以显示/隐藏 MainActivity 中的 ActionBar 项目。例如,我在 Tab1 中显示用于编写新消息的项目,进入 Tab2 中隐藏新消息项目并显示用于将用户添加到地址簿的项目... 应用程序的结构是:带有选项卡布局(4 个选项卡)的 MainActivity 以及管理所有 fragment 的 FragmentStatePagerAdapter。
主要 Activity
public class MainActivity extends AppCompatActivity {
// Declaring Your View and Variables
Toolbar toolbar;
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[]={"1","2","3","4"};
int Numboftabs =4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//getSupportActionBar().setElevation(0);
setContentView(R.layout.activity_main);
// Creating The Toolbar and setting it as the Toolbar for the activity
toolbar = (Toolbar) findViewById(R.id.tool_bar);
//setSupportActionBar(toolbar);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return ContextCompat.getColor(getApplicationContext(), R.color.darkgreen);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
@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;
}
@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();
switch (id) {
case R.id.action_settings:
Intent intentMSett = new Intent(this, MainSettings.class);
startActivity(intentMSett);
break;
case R.id.action_add_user:
Intent intent = new Intent(this, CreateUser.class);
startActivityForResult(intent, 101);
break;
case R.id.action_search:
Toast.makeText(getApplicationContext(),
"search", Toast.LENGTH_SHORT).show();
break;
}
return super.onOptionsItemSelected(item);
}
}
ViewPagerAdapter
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[]; // This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created
int NumbOfTabs; // Store the number of tabs, this will also be passed when the ViewPagerAdapter is created
private Context context;
// Build a Constructor and assign the passed Values to appropriate values in the class
public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
}
//This method return the fragment for the every position in the View Pager
@Override
public Fragment getItem(int position) {
if(position == 0) // if the position is 0 we are returning the First tab
{
Tab1 tab1 = new Tab1();
return tab1;
} else if(position == 1){
Tab2 tab2 = new Tab2();
return tab2;
} else if(position == 2) {
Tab3 tab3 = new Tab3();
return tab3;
} else if(position == 3) {
Tab4 tab4 = new Tab4();
return tab4;
} else {
Tab1 tab1 = new Tab1();
return tab1;
}
}
// This method return the titles for the Tabs in the Tab Strip
@Override
public CharSequence getPageTitle(int position) {
return Titles[position];
}
// This method return the Number of tabs for the tabs Strip
@Override
public int getCount() {
return NumbOfTabs;
}
}
在搜索解决方案时,我发现了 MainActivity 的此方法:
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
MenuInflater inflater = getMenuInflater();
int currentTab = tabHost.getCurrentTab();
Toast.makeText(getApplicationContext(), currentTab+"", Toast.LENGTH_SHORT);
menu.clear();
if (currentTab == 0) {
inflater.inflate(R.menu.first, menu); // menu for photospec.
} else {
inflater.inflate(R.menu.second, menu); // menu for songspec
}
return super.onPrepareOptionsMenu(menu);
}
滑动选项卡布局
public class SlidingTabLayout extends HorizontalScrollView {
/**
* Allows complete control over the colors drawn in the tab layout. Set with
* {@link #setCustomTabColorizer(TabColorizer)}.
*/
public interface TabColorizer {
/**
* @return return the color of the indicator used when {@code position} is selected.
*/
int getIndicatorColor(int position);
}
private static final int TITLE_OFFSET_DIPS = 24;
private static final int TAB_VIEW_PADDING_DIPS = 16;
private static final int TAB_VIEW_TEXT_SIZE_SP = 12;
private int mTitleOffset;
private int mTabViewLayoutId;
private int mTabViewTextViewId;
private boolean mDistributeEvenly;
private ViewPager mViewPager;
private SparseArray<String> mContentDescriptions = new SparseArray<String>();
private ViewPager.OnPageChangeListener mViewPagerPageChangeListener;
private final SlidingTabStrip mTabStrip;
public SlidingTabLayout(Context context) {
this(context, null);
}
public SlidingTabLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// Disable the Scroll Bar
setHorizontalScrollBarEnabled(false);
// Make sure that the Tab Strips fills this View
setFillViewport(true);
mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources().getDisplayMetrics().density);
mTabStrip = new SlidingTabStrip(context);
addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
}
/**
* Set the custom {@link TabColorizer} to be used.
*
* If you only require simple custmisation then you can use
* {@link #setSelectedIndicatorColors(int...)} to achieve
* similar effects.
*/
public void setCustomTabColorizer(TabColorizer tabColorizer) {
mTabStrip.setCustomTabColorizer(tabColorizer);
}
public void setDistributeEvenly(boolean distributeEvenly) {
mDistributeEvenly = distributeEvenly;
}
/**
* Sets the colors to be used for indicating the selected tab. These colors are treated as a
* circular array. Providing one color will mean that all tabs are indicated with the same color.
*/
public void setSelectedIndicatorColors(int... colors) {
mTabStrip.setSelectedIndicatorColors(colors);
}
/**
* Set the {@link ViewPager.OnPageChangeListener}. When using {@link SlidingTabLayout} you are
* required to set any {@link ViewPager.OnPageChangeListener} through this method. This is so
* that the layout can update it's scroll position correctly.
*
* @see ViewPager#setOnPageChangeListener(ViewPager.OnPageChangeListener)
*/
public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
mViewPagerPageChangeListener = listener;
}
/**
* Set the custom layout to be inflated for the tab views.
*
* @param layoutResId Layout id to be inflated
* @param textViewId id of the {@link TextView} in the inflated view
*/
public void setCustomTabView(int layoutResId, int textViewId) {
mTabViewLayoutId = layoutResId;
mTabViewTextViewId = textViewId;
}
/**
* Sets the associated view pager. Note that the assumption here is that the pager content
* (number of tabs and tab titles) does not change after this call has been made.
*/
public void setViewPager(ViewPager viewPager) {
mTabStrip.removeAllViews();
mViewPager = viewPager;
if (viewPager != null) {
viewPager.setOnPageChangeListener(new InternalViewPagerListener());
populateTabStrip();
}
}
/**
* Create a default view to be used for tabs. This is called if a custom tab view is not set via
* {@link #setCustomTabView(int, int)}.
*/
protected TextView createDefaultTabView(Context context) {
TextView textView = new TextView(context);
textView.setGravity(Gravity.CENTER);
textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP);
textView.setTypeface(Typeface.DEFAULT_BOLD);
textView.setLayoutParams(new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
TypedValue outValue = new TypedValue();
getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground,
outValue, true);
textView.setBackgroundResource(outValue.resourceId);
textView.setAllCaps(true);
int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density);
textView.setPadding(padding, padding, padding, padding);
return textView;
}
private void populateTabStrip() {
final PagerAdapter adapter = mViewPager.getAdapter();
final View.OnClickListener tabClickListener = new TabClickListener();
for (int i = 0; i < adapter.getCount(); i++) {
View tabView = null;
TextView tabTitleView = null;
if (mTabViewLayoutId != 0) {
// If there is a custom tab view layout id set, try and inflate it
tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip,
false);
tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
}
if (tabView == null) {
tabView = createDefaultTabView(getContext());
}
if (tabTitleView == null && TextView.class.isInstance(tabView)) {
tabTitleView = (TextView) tabView;
}
if (mDistributeEvenly) {
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams();
lp.width = 0;
lp.weight = 1;
}
tabTitleView.setText(adapter.getPageTitle(i));
tabView.setOnClickListener(tabClickListener);
String desc = mContentDescriptions.get(i, null);
if (desc != null) {
tabView.setContentDescription(desc);
}
mTabStrip.addView(tabView);
if (i == mViewPager.getCurrentItem()) {
tabView.setSelected(true);
}
}
}
private void addIconTab(final int position, int resId) {
ImageButton tab = new ImageButton(getContext());
tab.setImageResource(resId);
}
public void setContentDescription(int i, String desc) {
mContentDescriptions.put(i, desc);
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
if (mViewPager != null) {
scrollToTab(mViewPager.getCurrentItem(), 0);
}
}
private void scrollToTab(int tabIndex, int positionOffset) {
final int tabStripChildCount = mTabStrip.getChildCount();
if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) {
return;
}
View selectedChild = mTabStrip.getChildAt(tabIndex);
if (selectedChild != null) {
int targetScrollX = selectedChild.getLeft() + positionOffset;
if (tabIndex > 0 || positionOffset > 0) {
// If we're not at the first child and are mid-scroll, make sure we obey the offset
targetScrollX -= mTitleOffset;
}
scrollTo(targetScrollX, 0);
}
}
private class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
private int mScrollState;
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
int tabStripChildCount = mTabStrip.getChildCount();
if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
return;
}
mTabStrip.onViewPagerPageChanged(position, positionOffset);
View selectedTitle = mTabStrip.getChildAt(position);
int extraOffset = (selectedTitle != null)
? (int) (positionOffset * selectedTitle.getWidth())
: 0;
scrollToTab(position, extraOffset);
if (mViewPagerPageChangeListener != null) {
mViewPagerPageChangeListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
@Override
public void onPageScrollStateChanged(int state) {
mScrollState = state;
if (mViewPagerPageChangeListener != null) {
mViewPagerPageChangeListener.onPageScrollStateChanged(state);
}
}
@Override
public void onPageSelected(int position) {
if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
mTabStrip.onViewPagerPageChanged(position, 0f);
scrollToTab(position, 0);
}
for (int i = 0; i < mTabStrip.getChildCount(); i++) {
mTabStrip.getChildAt(i).setSelected(position == i);
}
if (mViewPagerPageChangeListener != null) {
mViewPagerPageChangeListener.onPageSelected(position);
}
}
}
private class TabClickListener implements View.OnClickListener {
@Override
public void onClick(View v) {
for (int i = 0; i < mTabStrip.getChildCount(); i++) {
if (v == mTabStrip.getChildAt(i)) {
mViewPager.setCurrentItem(i);
return;
}
}
}
}
}
但我不知道如何设置 getCurrentTab() 来获取 Tab 位置,而是在 ViewPagerAdapter 中我有该位置,但我不知道如何从 MainActivity 获取菜单。解决方案?
最佳答案
您可以使用setHasOptionMenu(Boolean)
;
然后在 onCreateOptionsMenu()
中创建图标和标题,下面是一个示例:
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.your_fragment_menu, menu);
//add the items here.
}
也看看这个example
编辑
在每个 fragment 上,您都可以膨胀菜单,就像我说的那样,您创建了两个菜单,因此在 onCreateOptionsMenu()
的一个 fragment 中添加第一个菜单,在第二个 fragment 中添加第二个菜单一个,等等。
关于android - 根据所选选项卡显示和隐藏 ActionBar 中的项目,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33693986/