java - 简单的 Android Activity 导致崩溃

Question

我开始为我的 Android 应用程序创建一个新的 Activity，当我测试它时，我遇到了一个问题。当我触摸按钮进入新 Activity 时，应用程序会崩溃并返回到主要 Activity 。

这是我的 Activity ，其中包含转到新 Activity 的按钮:

package brian.android.testgame;

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

public class BeginnerLevelSelector extends Activity {

protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.beginner_level_selector);

    Button level1button = (Button) findViewById(R.id.bl1);

    final Intent level1activity = new Intent(this, Level1Activity.class);

    level1button.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            startActivity(level1activity);
        }
    });

}

}

这是我的 Activity ，当我尝试启动它时崩溃(是的，这就是我在发现问题之前输入的所有内容)

package brian.android.testgame;

import android.app.Activity;
import android.os.Bundle;

public class Level1Activity extends Activity {

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_menu);

}

}

这是应用程序崩溃时我的日志:

05-06 21:07:29.085: E/AndroidRuntime(20391): FATAL EXCEPTION: main
05-06 21:07:29.085: E/AndroidRuntime(20391): android.content.ActivityNotFoundException: Unable to find explicit activity class {brian.android.testgame/brian.android.testgame.Level1Activity}; have you declared this activity in your AndroidManifest.xml?
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1634)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.app.Instrumentation.execStartActivity(Instrumentation.java:1510)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.app.Activity.startActivityForResult(Activity.java:3244)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.app.Activity.startActivity(Activity.java:3351)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at brian.android.testgame.BeginnerLevelSelector$1.onClick(BeginnerLevelSelector.java:22)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.view.View.performClick(View.java:3549)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.view.View$PerformClick.run(View.java:14400)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.os.Handler.handleCallback(Handler.java:605)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.os.Looper.loop(Looper.java:154)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at android.app.ActivityThread.main(ActivityThread.java:4944)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at java.lang.reflect.Method.invokeNative(Native Method)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at java.lang.reflect.Method.invoke(Method.java:511)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-06 21:07:29.085: E/AndroidRuntime(20391):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

如日志中所示:

.ActivityNotFoundException: Unable to find explicit activity class {brian.android.testgame/brian.android.testgame.Level1Activity};

表示您忘记在AndroidManifest.xml中注册Level1Activity Activity。所以将其声明为 AndroidManifest :

<activity android:name=".Level1Activity" />