菜单项(Menu)的初步认识 以及 多级菜单（SubMenu）的初步认识

MainActivity.class

public class MainActivity extends AppCompatActivity {
    private  TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView) findViewById(R.id.txt);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        //方法一、静态添加 xml方式添加菜单
//        getMenuInflater().inflate(R.menu.menu_main, menu);
        //方法二、动态添加 代码添加菜单项
        MenuItem item = menu.add(1, 100, 1, "赵1"); //参数(groupID , ItemID , order ,title)
        item.setTitle("aaa");
        menu.add(1,101,1,"赵2");
        menu.add(1,102,1,"赵3");
        menu.add(1,5,1,"赵4");

        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();

        //noinspection SimplifiableIfStatement
        switch (id){
            case 100:{
                Intent intent = new Intent(MainActivity.this,second_demo.class);
                item.setIntent(intent); //跳转到其他activity
                textView.setText("点击了" + id);
                break;
            }
            case 101:{
                textView.setText("点击了" + id);
                break;
            }
            case 102:{
                textView.setText("点击了" + id);
                break;
            }
            case 5:{
                textView.setText("点击了" + id);
                break;
            }
        }
        return super.onOptionsItemSelected(item);
    }
}

　　

---------------------------------------------------------------------------------------------我是华丽丽de分界线-------------------------------------------------------------------------------

SubMenu多级菜单 子菜单

方法一：动态加载

MainActivity.class

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //添加子菜单
        //addSubMenu有子菜单的主菜单
        SubMenu file = menu.addSubMenu("文件");
        SubMenu edit = menu.addSubMenu("编辑");
        //嵌套菜单SubMenu
        SubMenu A = menu.addSubMenu("第一层");
        SubMenu AA =  A.addSubMenu("第二层");
        SubMenu AAA =  AA.addSubMenu("第三层");
        AAA.add(3,1,1,"第四层");

        file.add(1,1,1,"新建");
        file.add(1,2,1,"打开");
        file.add(1,3,1,"保存");
        file.setHeaderTitle("文件de操作");

        edit.add(2, 1, 1, "复制");
        edit.add(2,2,1,"粘贴");
        edit.add(2,3,1,"剪切");
        edit.setHeaderTitle("编辑de操作");

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getGroupId() == 1){
            switch (item.getItemId()){
                case 1:
                    Toast.makeText(MainActivity.this,"点击了新建",Toast.LENGTH_SHORT).show();
                    break;
                case 2:
                    Toast.makeText(MainActivity.this,"点击了打开",Toast.LENGTH_SHORT).show();
                    break;
                case 3:
                    Toast.makeText(MainActivity.this,"点击了保存",Toast.LENGTH_SHORT).show();
                    break;
            }
        }else if(item.getGroupId() == 2){
            switch (item.getItemId()){
                case 1:
                    Toast.makeText(MainActivity.this,"点击了复制",Toast.LENGTH_SHORT).show();
                    break;
                case 2:
                    Toast.makeText(MainActivity.this,"点击了粘贴",Toast.LENGTH_SHORT).show();
                    break;
                case 3:
                    Toast.makeText(MainActivity.this,"点击了剪切",Toast.LENGTH_SHORT).show();
                    break;
            }
        }

        return super.onOptionsItemSelected(item);
    }
}

　　方法二、静态加载

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()){
            case R.id.edit_copy:
                Toast.makeText(MainActivity.this,"点击了copy",Toast.LENGTH_SHORT).show();
                break;
            case R.id.edit_jianqie:
                Toast.makeText(MainActivity.this,"点击了剪切",Toast.LENGTH_SHORT).show();
                break;
            case R.id.edit_nietian:
                Toast.makeText(MainActivity.this,"点击了粘贴",Toast.LENGTH_SHORT).show();
                break;
            case R.id.file_new:
                Toast.makeText(MainActivity.this,"点击了新建",Toast.LENGTH_SHORT).show();
                break;
            case R.id.file_open:
                Toast.makeText(MainActivity.this,"点击了打开",Toast.LENGTH_SHORT).show();
                break;
            case R.id.file_save:
                Toast.makeText(MainActivity.this,"点击了保存",Toast.LENGTH_SHORT).show();
                break;
        }

        return super.onOptionsItemSelected(item);
    }
}

　　menu_main.xml

<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=".MainActivity">
    <item
        android:id="@+id/file"
        android:title="文件"
        app:showAsAction="never" >

        <menu >
            <item
                android:id="@+id/file_new"
                app:showAsAction="never"
                android:title="新建"
                />
            <item
                android:id="@+id/file_open"
                app:showAsAction="never"
                android:title="打开"
                />
            <item
                android:id="@+id/file_save"
                app:showAsAction="never"
                android:title="保存"
                />
        </menu>

    </item>

    <item
        android:id="@+id/edit"
        android:title="编辑"
        app:showAsAction="never" >

        <menu>
            <item
                android:id="@+id/edit_copy"
                app:showAsAction="never"
                android:title="复制"
                />
            <item
                android:id="@+id/edit_nietian"
                app:showAsAction="never"
                android:title="粘贴"
                />
            <item
                android:id="@+id/edit_jianqie"
                app:showAsAction="never"
                android:title="剪切"
                />
        </menu>

    </item>

</menu>