java - 从菜单启动新 Activity

Question

我编写了一个简单的 Android 应用程序，但存在错误。当从菜单中打开第二个 Activity 时 - Android 停止了应用程序。

代码:Manifest.xml:

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="10" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Activit"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
    <activity android:name=".Activit2"/>
</manifest>

第一个 Activity :

  package com.example;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AdapterView.AdapterContextMenuInfo;

public class Activit extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

    }   

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

    switch(item.getItemId()){
case R.id.ok: Activ(); 

};  


    return super.onOptionsItemSelected(item);
}    

    private void Activ(){

        Intent inten=new Intent();
        inten.setClass(Activit.this, Activit2.class);
        startActivity(inten);   
    }

}

具有临时布局的第二个 Activity(与第一个 Activity 相同):

    package com.example;
    import android.app.Activity;
    import android.os.Bundle;
    public class Activit2 extends Activity{
        public void onCreate(Bundle savedInstanceState){
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
        }


}

Answer 1

您的标签<Activity />应该在标签 <application> 之内(而不是之外) :

试试这个:

<application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Activit"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

       <activity android:name=".Activit2"/> // you should declare your activity Here
    </application>