Android三种菜单的使用方式

一、选项菜单(OptionMenu)

• 在res目录下新建menu目录，用于放置菜单布局文件(右键res->new->Android Resource Directory->menu)
• 在menu下创建菜单布局文件，根标签为menu,menu下面有多个group,group下面有多个item.
  
  简单示例如下：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/oi_1"
        android:title="编程语言"
        android:checkable="true"></item>
    <item
        android:id="@+id/oi_2"
        android:checkable="true"
        android:title="算法"></item>
</menu>

• 重写Activity的onCreateOptionsMenu方法

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    //根据菜单布局文件填充菜单项
    getMenuInflater().inflate(R.menu.menu_options, menu);
    return true;
}

• 监听菜单项

@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
        case R.id.oi_1:
            doSomething....
            return true;
        case R.id.oi_2:
            doSomething....
            return true;
        case R.id.oi_3:
            doSomething....
            return true;
        case R.id.oi_4:
            doSomething....
            return true;
        default:
            doSomething....
            return super.onOptionsItemSelected(item);
    }
}

二、上下文菜单

• 创建菜单布局文件
• 为指定view(可以是Button，TextView等等)注册上下文菜单

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_context_menu);
    //这是一个按钮
    Button colorSelector = findViewById(R.id.btn_color_selector);
    //为button注册上下文菜单
    registerForContextMenu(colorSelector);
}

• 重写Activity的onCreateOptionsMenu方法

@Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        //为菜单设置title
        menu.setHeaderTitle("please select your favorite color:");
        //填充菜单项
        getMenuInflater().inflate(R.menu.menu_context, menu);
    }

• 监听菜单项

@Override
public boolean onContextItemSelected(@NonNull MenuItem item) {
    switch(item.getItemId()){
        case R.id.ci_red:
            colorSelector.setBackgroundColor(Color.parseColor("red"));
            return true;
        case R.id.ci_purple:
            colorSelector.setBackgroundColor(Color.parseColor("purple"));
            return true;
        case R.id.ci_white:
            colorSelector.setBackgroundColor(Color.parseColor("white"));
            return true;
    }
    return super.onContextItemSelected(item);
}

• 取消注册

@Override
protected void onDestroy() {
    super.onDestroy();
    //取消注册，防止内存溢出
    unregisterForContextMenu(colorSelector);
}

三、弹出式菜单

• 创建菜单布局文件
• 监听指定view点击事件，同时构建弹出菜单对象

//这是对应button的点击监听事件
public void showPopupMenu(View view) {
    final PopupMenu menu = new PopupMenu(PopupMenuActivity.this, view);
    getMenuInflater().inflate(R.menu.menu_popup, menu.getMenu());
    menu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            switch (item.getItemId()) {
                case R.id.pi_hide:
                    //菜单隐藏
                    menu.dismiss();
                    return true;
                default:
                    Toast.makeText(PopupMenuActivity.this, item.getTitle(), Toast.LENGTH_SHORT).show();
                    return true;
            }
        }
    });
    menu.show();
}