上下文菜单案例

怼烎@ 2024-03-30 10:23 80阅读 0赞

**目录**

基于Empty Activity模板创建安卓应用 ContextMenuDemo

将图片素材拷贝到drawable目录

打开字符串资源文件strings.xml输入代码

打开主布局资源文件acitivity\_main.xml输入代码：

打开主界面类MainActivity输入代码：

--------------------

#### 基于`Empty Activity`模板创建安卓应用 `ContextMenuDemo` ####

![7e4eeb308efb467684e4ace03408c938.png][]

![72e40da6abab4272a05bed1878ec7635.png][]

#### 将图片素材拷贝到`drawable`目录 ####

![330e6230d4b5413ca0335f8fe892023f.png][]

#### 打开字符串资源文件`strings.xml输入代码` ####

![802a03d56ea14cbb93bbef845fa9d9bf.png][]

具体代码：

<resources>
        <string name="app_name">上下文菜单演示</string>
        <string name="file">文件</string>
        <string name="edit">编辑</string>
    </resources>

#### 打开主布局资源文件`acitivity_main.xml输入代码：` ####

![02b9df100ec64ca3aad7ad6b788f2cfb.png][]

具体代码：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/background"
        tools:context=".MainActivity">
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:padding="10dp"
            android:background="#eeeeee">
    
            <TextView
                android:id="@+id/tv_file"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginRight="15dp"
                android:text="@string/file"
                android:textColor="#0000ff"
                android:textSize="20sp" />
    
            <TextView
                android:id="@+id/tv_edit"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/edit"
                android:textColor="#0000ff"
                android:textSize="20sp" />
        </LinearLayout>
    </LinearLayout>

#### 打开主界面类`MainActivity输入代码：` ####

![3a8d3dd4a15641cda629b0495f64e8ce.png][]

![b85365633aeb4ab58ac9f9954660f477.png][]

具体代码：

package net.zyt.contextmenudemo;
    
    import androidx.annotation.NonNull;
    import androidx.appcompat.app.AppCompatActivity;
    
    import android.os.Bundle;
    import android.view.ContextMenu;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.TextView;
    import android.widget.Toast;
    
    import java.lang.reflect.Method;
    
    public class MainActivity extends AppCompatActivity {
        private TextView tvFile;//文件标签
        private TextView tvEdit;//编辑标签
    
        private static final int NEW_FILE_MENU_ITEM=1;//新建文件菜单项标识
        private static final int OPEN_FILE_MENU_ITEM=2;//打开文件菜单项标识
        private static final int SAVE_FILE_MENU_ITEM=3;//保存文件菜单项标识
        private static final int EXIT_FILE_MENU_ITEM=4;//退出文件菜单项标识
    
        private static final int CUT_MENU_ITEM=5;//剪切菜单项标识
        private static final int COPY_MENU_ITEM=6;//复制菜单项标识
        private static final int PASTE_MENU_ITEM=7;//粘贴菜单项标识
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //利用布局资源文件设置用户界面
            setContentView(R.layout.activity_main);
            //通过资源标识符获取控件实例
            tvFile=findViewById(R.id.tv_file);
            tvEdit=findViewById(R.id.tv_edit);
            //给两个标签控件注册上下文菜单
            registerForContextMenu(tvFile);
            registerForContextMenu(tvEdit);
    
        }
        /**
         * 设置图标可用的方法
         *
         * @param menu
         * @param enabled
         */
        private void setIconEnabled(Menu menu, boolean enabled) {
            try {
                Class<?> clazz = Class.forName("com.android.internal.view.menu.MenuBuilder");
                Method m = clazz.getDeclaredMethod("setOptionalIconsVisible", boolean.class);
                m.setAccessible(true);
                // MenuBuilder实现Menu接口，创建菜单时，传进来的menu其实就是MenuBuilder对象（Java的多态特征）
                m.invoke(menu, enabled);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
    @Override
        public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo){
            super.onCreateContextMenu(menu,v,menuInfo);
            //设置菜单图标可用
            setIconEnabled(menu,true);
            //针对不同控件创建不同的上下菜单
            switch (v.getId()){
                case R.id.tv_file://文件标签
                    //设置标题图标
                    menu.setHeaderIcon(R.drawable.file);
                    //设置菜单标题
                    menu.setHeaderTitle(R.string.file);
                    //添加菜单项(组标识，菜单项标识，菜单项序号,菜单项标题)
                    menu.add(1,NEW_FILE_MENU_ITEM,1,"新建文件").setIcon(R.drawable.new_file);
                    menu.add(1,OPEN_FILE_MENU_ITEM,2,"打开文件").setIcon(R.drawable.open_file);
                    menu.add(1,SAVE_FILE_MENU_ITEM,3,"保存文件").setIcon(R.drawable.save_file);
                    menu.add(1,EXIT_FILE_MENU_ITEM,4,"退出文件").setIcon(R.drawable.exit_app);
                    break;
                case R.id.tv_edit://编辑标签
                    //设置菜单图标
                    menu.setHeaderIcon(R.drawable.edit);
                    //设置菜单标题
                    menu.setHeaderTitle(R.string.edit);
                    //添加菜单项(组标识，菜单项标识，菜单项序号,菜单项标题)
                    menu.add(2,CUT_MENU_ITEM,1,"剪切").setIcon(R.drawable.cut);
                    menu.add(2,COPY_MENU_ITEM,2,"复制").setIcon(R.drawable.copy);
                    menu.add(2,PASTE_MENU_ITEM,3,"粘贴").setIcon(R.drawable.paste);
                    break;
            }
    }
    //上下文菜单项选择事件处理方法
        @Override
        public boolean onContextItemSelected(@NonNull MenuItem item) {
            //判断用湖选择了哪个菜单项
            switch (item.getItemId()){
                case NEW_FILE_MENU_ITEM://新建文件菜单项
                    Toast.makeText(this,"你单击了【新建文件】菜单项！",Toast.LENGTH_SHORT).show();
                    break;
                case OPEN_FILE_MENU_ITEM://打开文件菜单项
                    Toast.makeText(this,"你单击了【打开文件】菜单项！",Toast.LENGTH_SHORT).show();
                    break;
                case SAVE_FILE_MENU_ITEM://保存文件菜单项
                    Toast.makeText(this,"你单击了【保存文件】菜单项！",Toast.LENGTH_SHORT).show();
                    break;
                case EXIT_FILE_MENU_ITEM://退出文件菜单项
                    finish();//关闭当前窗口退出应用
                    break;
                case CUT_MENU_ITEM://剪切菜单项
                    Toast.makeText(this,"你单击了【剪切】菜单项！",Toast.LENGTH_SHORT).show();
                    break;
                case COPY_MENU_ITEM://复制菜单项
                    Toast.makeText(this,"你单击了【复制】菜单项！",Toast.LENGTH_SHORT).show();
                    break;
                case PASTE_MENU_ITEM://粘贴菜单项
                    Toast.makeText(this,"你单击了【粘贴】菜单项！",Toast.LENGTH_SHORT).show();
            }
            return true;
        }
    }

最后效果：

![1de9c1fed1014a489306cceebd109e76.gif][]

[7e4eeb308efb467684e4ace03408c938.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/eeeb40ed2e46468fafd0d65830fa5909.png
[72e40da6abab4272a05bed1878ec7635.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/518c94195a274c90b0787647c0b07ec8.png
[330e6230d4b5413ca0335f8fe892023f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/27ba8d0ff0c8487eadcfaff2ddf39c1a.png
[802a03d56ea14cbb93bbef845fa9d9bf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/79d0108db66448e1b455beddc61aebb3.png
[02b9df100ec64ca3aad7ad6b788f2cfb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/da7149df80be43e7933e9c7a5a3f572e.png
[3a8d3dd4a15641cda629b0495f64e8ce.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/93463a1d11fe4c689b519f986cf8d30e.png
[b85365633aeb4ab58ac9f9954660f477.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/0a760203195e4ce18f235dfc04be2724.png
[1de9c1fed1014a489306cceebd109e76.gif]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/db263935ff024f4d915fdcc10209c3db.gif