ContextMenu与TabHost

1、ContextMenu

第一种ContextMenu

public class MainActivity extends AppCompatActivity {

    private Button mButton;

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

        mButton = findViewById(R.id.button);

        mButton.setOnCreateContextMenuListener(MainActivity.this);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                v.showContextMenu();
            }
        });
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.context_menu, menu);
    }

    //点击事件处理
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.text1:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            case R.id.text2:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            case R.id.text3:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            default:
                break;
        }
        return super.onContextItemSelected(item);
    }
}

在res文件夹下创建menu文件夹，再创建context_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/text1"
        android:title="文本1"
        />
    <item android:id="@+id/text2"
        android:title="文本2"
        />

    <item android:id="@+id/text3"
        android:title="文本3"
        />
</menu>

第二种ContextMenu

public class MainActivity extends AppCompatActivity {

    private ArrayList<String> mList;
    private ListView mListView;

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

        mListView = findViewById(R.id.listView);

        mList = new ArrayList<>();
        for(int i = 0 ; i < 3; i++) {
            mList.add("文本" + i);
        }

        mListView.setAdapter(new ArrayAdapter<String>(
                MainActivity.this,
                android.R.layout.simple_expandable_list_item_1,
                mList
        ));
        /*为listView添加（）注册上下文菜单*/
        registerForContextMenu(mListView);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        //获取适配器
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        //设置标题
        menu.setHeaderTitle(mList.get(info.position));
        /*设置选项内容*/
        //参数一：组，参数二：项目编号 参数三：位置
        menu.add(0,1,0, "嘤嘤嘤");
        menu.add(0,2,0, "噫噫噫");
        menu.add(0,3,0, "呀呀呀");
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case 1:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            case 2:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            case 3:
                Toast.makeText(MainActivity.this,"你点击了" + item.getTitle(), Toast.LENGTH_SHORT).show();
                break;

            default:
                break;
        }
        return super.onContextItemSelected(item);
    }
}

activity_main.xml

<LinearLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.admin.vip_10.MainActivity">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    </ListView>

</LinearLayout>

注意一点就是此处弹出ContextMenu需要长按。

2、TabHost

第一种TabHost写法：

<TabHost android:layout_height="match_parent"
    android:layout_width="match_parent"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

        </TabWidget>

        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            >

            <LinearLayout
                android:id="@+id/layout_1"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/colorPrimaryDark"
                android:orientation="vertical"
                >

            </LinearLayout>

            <LinearLayout
                android:id="@+id/layout_2"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/colorAccent"
                android:orientation="vertical"
                >

            </LinearLayout>
        </FrameLayout>

    </LinearLayout>
</TabHost>

需要注意的地方：
1. TabHost id必须是 android:id=”@android:id/tabhost”
2. TabWidget id必须是 android:id=”@android:id/tabs”
3. FrameLayout id必须是 android:id=”@android:id/tabcontent”

//注意继承TabActivity
public class MainActivity extends TabActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        TabHost tabHost = getTabHost();
        tabHost.addTab(
                tabHost.newTabSpec("1").setIndicator("layout_1").setContent(R.id.layout_1)
        );
        tabHost.addTab(
                tabHost.newTabSpec("2").setIndicator("layout_2").setContent(R.id.layout_2)
        );
    }
}

第二种TabHost的写法：

activity_main.xml文件中几乎一样的要求，但是其中的TabHost的id可以自定义。

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        TabHost tabHost = findViewById(R.id.myTabHost);

        //启动tabHost
        tabHost.setup();

        TabHost.TabSpec spec1 = tabHost.newTabSpec("1");
        spec1.setIndicator("layout_1");
        spec1.setContent(R.id.layout_1);

        TabHost.TabSpec spec2 = tabHost.newTabSpec("2");
        spec2.setIndicator("layout_2");
        spec2.setContent(R.id.layout_2);

        //别忘了添加到tabHost中
        tabHost.addTab(spec1);
        tabHost.addTab(spec2);
    }
}