Question

大家好我正在尝试创建菜单和子菜单。菜单部分工作正常，但每次长按调用子菜单的文本，应用程序崩溃。请问我做错了什么？这是我的代码：

    package com.santia.myfirstapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.View;
import android.widget.TextView;

public class BuildingMenus extends Activity {
    private final int menuAdd = 1, menuSend = 2, menuDel = 3;
    private final int groupDefault = 0, groupDel= 1;
    private final int idDefault = 0;
    private final int idText1= 1, idText2 = 2, idText3 = 3;
    private String[] Choices={"Press Me", "Try Again", "Change Me"};
    private static int itemNum=0;
    private static TextView txt;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.menu.bm);
        txt = (TextView) findViewById(R.id.txtT);
        registerForContextMenu((View) findViewById(R.id.txtT));
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        menu.add(groupDefault, menuAdd, 0, "Add").setIcon(R.drawable.ic_launcher);
        menu.add(groupDefault, menuSend, 0, "Send");
        menu.add(groupDel, menuDel, 0, "Delete");
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        if(itemNum>0){
            menu.setGroupVisible(groupDel, true);
        }else { 
            menu.setGroupVisible(groupDel, false);
        }
        return super.onPrepareOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        switch(item.getItemId()){
        case menuAdd:
            create_note();
            return true;
        case menuSend:
            send_note();
            return true;
        case menuDel:
            delete_note();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        // TODO Auto-generated method stub
        if (v.getId()==R.id.txtT){
            SubMenu textmenu = menu.addSubMenu("Change Text");
            textmenu.add(0, idText1, 0, Choices[0]);
            textmenu.add(0, idText2, 0, Choices[1]);
            textmenu.add(0, idText3, 0, Choices[3]);
            textmenu.add(0, idDefault, 0, "Original Text");
        }
        super.onCreateContextMenu(menu, v, menuInfo);

    }
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        switch(item.getItemId()){
        case idDefault:
            txt.setText(R.string.hello_world);
            return true;
        case idText1:
        case idText2:
        case idText3:
            txt.setText(Choices[item.getItemId()-1]);
        }
        return super.onContextItemSelected(item);
    }

    private void delete_note() {
        // TODO Auto-generated method stub
        itemNum--;
    }
    private void send_note() {
        // TODO Auto-generated method stub

    }
    private void create_note() {
        // TODO Auto-generated method stub
        itemNum++;
    }
}

这是logcat的错误

07-22 21:13:18.395: E/AndroidRuntime(665): FATAL EXCEPTION: main
07-22 21:13:18.395: E/AndroidRuntime(665): java.lang.ArrayIndexOutOfBoundsException: length=3; index=3
07-22 21:13:18.395: E/AndroidRuntime(665):  at com.santia.myfirstapp.BuildingMenus.onCreateContextMenu(BuildingMenus.java:72)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.View.createContextMenu(View.java:6121)
07-22 21:13:18.395: E/AndroidRuntime(665):  at com.android.internal.view.menu.ContextMenuBuilder.show(ContextMenuBuilder.java:81)
07-22 21:13:18.395: E/AndroidRuntime(665):  at com.android.internal.policy.impl.PhoneWindow$DecorView.showContextMenuForChild(PhoneWindow.java:2124)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:566)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:566)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:566)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.View.showContextMenu(View.java:3532)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.View.performLongClick(View.java:3501)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.widget.TextView.performLongClick(TextView.java:9228)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.view.View$CheckForLongPress.run(View.java:13961)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.os.Handler.handleCallback(Handler.java:605)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.os.Handler.dispatchMessage(Handler.java:92)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.os.Looper.loop(Looper.java:137)
07-22 21:13:18.395: E/AndroidRuntime(665):  at android.app.ActivityThread.main(ActivityThread.java:4340)
07-22 21:13:18.395: E/AndroidRuntime(665):  at java.lang.reflect.Method.invokeNative(Native Method)
07-22 21:13:18.395: E/AndroidRuntime(665):  at java.lang.reflect.Method.invoke(Method.java:511)
07-22 21:13:18.395: E/AndroidRuntime(665):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-22 21:13:18.395: E/AndroidRuntime(665):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-22 21:13:18.395: E/AndroidRuntime(665):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

Choices [3]不是该数组的有效索引。使用选择[2]。

在android中创建菜单和子菜单

1 个答案: