Question

我正在尝试从我的主要活动中启动一项新活动，但我一直都会收到错误代码。

继承我的主要活动;

   package com.gunstats;



import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class gunstats extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main); 


        final MediaPlayer mp = MediaPlayer.create(this, R.raw.deagle);

        Button button3 = (Button)this.findViewById(R.id.button3);
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mp.start();


            }

        });

        final MediaPlayer mp2 = MediaPlayer.create(this, R.raw.ak47);

        Button button2 = (Button)this.findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mp2.start();

            }

        });


        final MediaPlayer mp3 = MediaPlayer.create(this, R.raw.m40a3);

        Button button1 = (Button)this.findViewById(R.id.button1);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mp3.start();

            }
        });



        Button button4 = (Button)findViewById(R.id.button4);
                button4.setOnClickListener(new Button.OnClickListener() {
                    public void onClick(View v) {

                        Intent intent = new Intent(gunstats.this,
                                more.class);
                                                 startActivity(intent);
                                            }
                                        });

    }

}

以及从我的主类调用的活动;

package com.gunstats;



import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;


public class more extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main); 


        final MediaPlayer mp = MediaPlayer.create(this, R.raw.deagle);

        Button buttonm1 = (Button)this.findViewById(R.id.buttonm1);
        buttonm1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mp.start();


            }

        });


    }

}

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.gunstats"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".gunstats"
                  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=".more"/>

    </application>

    <uses-sdk android:minSdkVersion="4" />

</manifest>

logcat的：

01-08 17:37:47.658: ERROR/AndroidRuntime(276): Uncaught handler: thread main exiting due to uncaught exception
01-08 17:37:47.728: ERROR/AndroidRuntime(276): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gunstats/com.gunstats.more}: java.lang.NullPointerException
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.access$2100(ActivityThread.java:116)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.os.Looper.loop(Looper.java:123)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.main(ActivityThread.java:4203)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at java.lang.reflect.Method.invokeNative(Native Method)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at java.lang.reflect.Method.invoke(Method.java:521)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at dalvik.system.NativeStart.main(Native Method)
01-08 17:37:47.728: ERROR/AndroidRuntime(276): Caused by: java.lang.NullPointerException
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at com.gunstats.more.onCreate(more.java:23)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
01-08 17:37:47.728: ERROR/AndroidRuntime(276):     ... 11 more

错误指向“更多”类中的23行。

我的23行是; buttonm1.setOnClickListener（new View.OnClickListener（）{

怎么了？

Answer 1

清单中没有错误

我想可能有。此错误行：

android.content.ActivityNotFoundException: Unable to find explicit activity class {com.gunstats/com.gunstats.more}; have you declared this activity in your AndroidManifest.xml? 01-08

建议您尚未在清单中定义Activity“more”。检查它是否已定义。

此外，Java约定是类名首字母大写。因此，该类应该被称为More。

Answer 2

您应该将“更多”活动添加到AndroidManifest.xml

开始新活动时强制关闭

2 个答案: