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Android - Context Menu

当用户长按元素时，将显示Android上下文菜单。也称为浮动菜单。

上下文菜单示例

让无涯教程看看Android中的上下文菜单的简单示例。从面板上拖出一个listview，现在xml文件如下所示：

File: activity_main.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<android.support.constraint.constraintlayout
    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="example.learnfk.com.contextmenu.MainActivity">
    <listview android:layout_width="368dp" android:layout_height="495dp" android:id="@+id/listView" android:layout_marginend="8dp" android:layout_marginstart="8dp" android:layout_margintop="8dp" app:layout_constraintend_toendof="parent" app:layout_constrainthorizontal_bias="0.0" app:layout_constraintstart_tostartof="parent" app:layout_constrainttop_totopof="parent"></listview>
</android.support.constraint.constraintlayout>

在菜单目录中在菜单目录中创建一个单独的menu_main.xml文件。

复制代码

<!--?xml version="1.0" encoding="utf-8"?-->
<menu
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/call" android:title="Call"></item>
    <item android:id="@+id/sms" android:title="SMS"></item>
</menu>

让无涯教程编写代码以在按列表视图上显示上下文菜单。

File: MainActivity.java

复制代码

package example.learnfk.com.contextmenu;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ListView listView;
    String contacts[]={"Ajay","Sachin","Sumit","Tarun","Yogesh"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView=(ListView)findViewById(R.id.listView);
        ArrayAdapter<string> adapter=new ArrayAdapter<string>(this,android.R.layout.simple_list_item_1,contacts);
        listView.setAdapter(adapter);
       //为上下文菜单注册 ListView
        registerForContextMenu(listView);
    }
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo)
    {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main, menu);
        menu.setHeaderTitle("Select The Action");
    }
    @Override
    public boolean onContextItemSelected(MenuItem item){
        if(item.getItemId()==R.id.call){
            Toast.makeText(getApplicationContext(),"calling code",Toast.LENGTH_LONG).show();
        }
        else if(item.getItemId()==R.id.sms){
            Toast.makeText(getApplicationContext(),"sending sms code",Toast.LENGTH_LONG).show();
        }else{
            return false;
        }
        return true;
    }
}