Android動態修改ToolBar的Menu菜單

　　剛好工作需要，動態去修改Menu菜單里面Title或其他顯示狀態，然后查到這篇文章。他主要實現有兩步，一個是invalidateOptionsMenu是通知要刷新菜單。而刷新菜單的方法就是重寫onPrepareOptionsMenu方法，通過里面內置傳的menu值可以修改到菜單Ttile

 

效果圖

實現

實現很簡單，就是一個具有3個Action的Menu，在我們滑動到不同狀態的時候，把對應的Action隱藏了。
開始上貨

Menu

       Menu下添加3個Item

 

<menu 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"
    tools:context="com.kongqw.myapplication.MainActivity">
    <item
        android:id="@+id/search_button"
        android:icon="@mipmap/navigation_icon_search"
        android:orderInCategory="100"
        android:title="搜索"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/scan_button"
        android:icon="@mipmap/navigation_icon_sweep"
        android:orderInCategory="100"
        android:title="掃描"
        app:showAsAction="ifRoom" />

    <item
        android:id="@+id/setting_button"
        android:icon="@mipmap/titlebar_icon_settings_normal"
        android:orderInCategory="100"
        android:title="設置"
        app:showAsAction="ifRoom" />
</menu>

重寫onPrepareOptionsMenu方法

　　用來根據ViewPager顯示頁面控制Menu顯示的Item
　　Demo里我用的是ViewPager滑動來控制，可以根據自己需求，不過大多數都是判斷ViewPager吧。

 

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    // 動態設置ToolBar狀態
    switch (mViewPager.getCurrentItem()) {
        case 0:
            menu.findItem(R.id.search_button).setVisible(true);
            menu.findItem(R.id.scan_button).setVisible(true);
            menu.findItem(R.id.setting_button).setVisible(false);
            break;
        case 1:
            menu.findItem(R.id.search_button).setVisible(false);
            menu.findItem(R.id.scan_button).setVisible(false);
            menu.findItem(R.id.setting_button).setVisible(false);
            break;
        case 2:
            menu.findItem(R.id.search_button).setVisible(false);
            menu.findItem(R.id.scan_button).setVisible(false);
            menu.findItem(R.id.setting_button).setVisible(true);
            break;
    }
    return super.onPrepareOptionsMenu(menu);
}

 

Item點擊

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.search_button) {
        Toast.makeText(getApplicationContext(), "搜索", Toast.LENGTH_SHORT).show();
        return true;
    } else if (id == R.id.scan_button) {
        Toast.makeText(getApplicationContext(), "掃描", Toast.LENGTH_SHORT).show();
        return true;
    } else if (id == R.id.setting_button) {
        Toast.makeText(getApplicationContext(), "設置", Toast.LENGTH_SHORT).show();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

 

監聽ViewPager滑動，改變Menu狀態（重點）

調用invalidateOptionsMenu();方法從新加載Menu，即回調onPrepareOptionsMenu方法

mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override
    public void onPageSelected(int position) {
        // getWindow().invalidatePanelMenu(Window.FEATURE_OPTIONS_PANEL);
        invalidateOptionsMenu();
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
});

 

Code（參考）

就是Android Studio默認創建的帶有ViewPager的Demo，

package com.kongqw.myapplication; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.os.Bundle; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends AppCompatActivity { private SectionsPagerAdapter mSectionsPagerAdapter; private ViewPager mViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); mViewPager = (ViewPager) findViewById(R.id.container); mViewPager.setAdapter(mSectionsPagerAdapter); mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { // getWindow().invalidatePanelMenu(Window.FEATURE_OPTIONS_PANEL); invalidateOptionsMenu(); } @Override public void onPageScrollStateChanged(int state) { } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onPrepareOptionsMenu(Menu menu) { // 動態設置ToolBar狀態 switch (mViewPager.getCurrentItem()) { case 0: menu.findItem(R.id.search_button).setVisible(true); menu.findItem(R.id.scan_button).setVisible(true); menu.findItem(R.id.setting_button).setVisible(false); break; case 1: menu.findItem(R.id.search_button).setVisible(false); menu.findItem(R.id.scan_button).setVisible(false); menu.findItem(R.id.setting_button).setVisible(false); break; case 2: menu.findItem(R.id.search_button).setVisible(false); menu.findItem(R.id.scan_button).setVisible(false); menu.findItem(R.id.setting_button).setVisible(true); break; } return super.onPrepareOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == R.id.search_button) { Toast.makeText(getApplicationContext(), "搜索", Toast.LENGTH_SHORT).show(); return true; } else if (id == R.id.scan_button) { Toast.makeText(getApplicationContext(), "掃描", Toast.LENGTH_SHORT).show(); return true; } else if (id == R.id.setting_button) { Toast.makeText(getApplicationContext(), "設置", Toast.LENGTH_SHORT).show(); return true; } return super.onOptionsItemSelected(item); } public static class PlaceholderFragment extends Fragment { private static final String ARG_SECTION_NUMBER = "section_number"; public PlaceholderFragment() { } public static PlaceholderFragment newInstance(int sectionNumber) { PlaceholderFragment fragment = new PlaceholderFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_main, container, false); TextView textView = (TextView) rootView.findViewById(R.id.section_label); textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER))); return rootView; } } public class SectionsPagerAdapter extends FragmentPagerAdapter { public SectionsPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { return PlaceholderFragment.newInstance(position + 1); } @Override public int getCount() { return 3; } @Override public CharSequence getPageTitle(int position) { switch (position) { case 0: return "SECTION 1"; case 1: return "SECTION 2"; case 2: return "SECTION 3"; } return null; } } }