当从菜单中选择帮助(alertdialog)选项时，应用程序停止工作

Question

伙计们，我试着在android上开发一个简单的应用程序，它在操作栏上有一个溢出按钮。但是当我在模拟器中运行应用程序并选择帮助选项时，应用程序停止工作。我不知道问题是什么，我完全是初学者。请帮我整理一下

Thanks in advance以下是我使用的代码

MainActivity.java

package mai.app.speak2speak;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle item selection
        switch (item.getItemId()) {
        case R.id.help_option:
            final AlertDialog alertDialog = new AlertDialog.Builder(this).create();
            alertDialog.setTitle("Help :");
            alertDialog.setMessage("Welcome to AndroidHive.info");
            alertDialog.setButton(1,"OK", new OnClickListener() {
                @Override
                public void onClick(final DialogInterface dialog, final int which) {
                    // TODO Auto-generated method stub
                    alertDialog.cancel();
                }
            });
            alertDialog.show();


            return true;
        case R.id.quit_option:
            finish();
            return true;
        case R.id.rate_option:

            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
}

    }

main。xml

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    <item
        android:id="@+id/more_options"
        android:showAsAction="always"
        android:icon="@drawable/ic_action_overflow" >
<menu >
    <item
        android:id="@+id/rate_option"
        android:orderInCategory="100"
        android:showAsAction="ifRoom"
        android:title="@string/rate"/>
    <item
        android:id="@+id/help_option"
        android:orderInCategory="100"
        android:showAsAction="ifRoom"
        android:title="@string/help"/>
     <item
        android:id="@+id/quit_option"
        android:orderInCategory="100"
        android:showAsAction="ifRoom"
        android:title="@string/quit"/>
     </menu>
    </item>
</menu>

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="mai.app.speak2speak"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk
        android:minSdkVersion="9"
        android:targetSdkVersion="9" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="mai.app.speak2speak.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Answer 1

尝试更改

final AlertDialog alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle("Help :");
alertDialog.setMessage("Welcome to AndroidHive.info");
alertDialog.setButton(1,"OK", new OnClickListener() {
    @Override
    public void onClick(final DialogInterface dialog, final int which) {
        // TODO Auto-generated method stub
        alertDialog.cancel();
    }
});
alertDialog.show();

final AlertDialog alertDialog = new AlertDialog.Builder(this)
.setTitle("Help :")
.setMessage("Welcome to AndroidHive.info")
.setNegativeButton("OK", new OnClickListener() {
    @Override
    public void onClick(final DialogInterface dialog, final int which) {
        // TODO Auto-generated method stub
        alertDialog.cancel();
    }
})
.create();
alertDialog.show();