所以我刚刚开始设置一个显示5秒的启动画面，然后转到我的主菜单。我认为我在这个过程中标记了一些错误，现在我的应用程序正在关闭。我很确定这是我的活动和我的清单的问题。
DragonFruitActivity.java：
package com.Dragon_Fruit;
import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageButton;
public class DragonFruitActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
Thread logoTimer = new Thread() {
public void run() {
try {
sleep(5000);
DragonFruitActivity.this.setContentView(R.layout.main);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
finish();
}
}
};
logoTimer.start();
// ***BUTTON SOUND***//
final MediaPlayer buttonSound = MediaPlayer.create(
DragonFruitActivity.this, R.raw.button_click);
ImageButton playbutton = (ImageButton) findViewById(R.id.playbutton);
playbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
arg0.setBackgroundResource(R.drawable.playbuttonselected);
// TODO Auto-generated method stub
buttonSound.start();
startActivity(new Intent(DragonFruitActivity.this,
playbutton.class));
}
});
ImageButton settingsbutton = (ImageButton) findViewById(R.id.settingsbutton);
settingsbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
buttonSound.start();
startActivity(new Intent(DragonFruitActivity.this,
settingsbutton.class));
}
});
}
}
Dragon Fruit Manifest：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.Dragon_Fruit"
android:versionCode="1"
android:versionName="1.0"
android:installLocation="preferExternal">
<application android:icon="@drawable/icon"
android:label="@string/app_name"
android:debuggable="true">
<activity android:name=".DragonFruitActivity"
android:label="@string/app_name"
android:screenOrientation="landscape"
android:configChanges="keyboard|keyboardHidden|orientation">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".playbutton"
android:label="@string/app_name"
android:screenOrientation="landscape"
android:configChanges="keyboard|keyboardHidden|orientation">
<intent-filter>
<action android:name="com.Dragon_Fruit.PLAYBUTTON" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:name=".settingsbutton"
android:label="@string/app_name"
android:screenOrientation="landscape"
android:configChanges="keyboard|keyboardHidden|orientation">
<intent-filter>
<action android:name="com.Dragon_Fruit.SETTINGSBUTTON" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-sdk android:minSdkVersion="3" android:targetSdkVersion="9" />
</manifest>
logcat的：
08-06 22:46:27.942: ERROR/dalvikvm(9896): could not disable core file generation for pid 9896, errno=1
08-06 22:46:28.271: ERROR/(5531): This file is not ASF file.
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): FATAL EXCEPTION: main
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Dragon_Fruit/com.Dragon_Fruit.DragonFruitActivity}: java.lang.NullPointerException
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2737)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2753)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread.access$2500(ActivityThread.java:129)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2107)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.os.Handler.dispatchMessage(Handler.java:99)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.os.Looper.loop(Looper.java:143)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread.main(ActivityThread.java:4701)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at java.lang.reflect.Method.invokeNative(Native Method)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at java.lang.reflect.Method.invoke(Method.java:521)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at dalvik.system.NativeStart.main(Native Method)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): Caused by: java.lang.NullPointerException
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at com.Dragon_Fruit.DragonFruitActivity.onCreate(DragonFruitActivity.java:44)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2701)
08-06 22:46:28.364: ERROR/AndroidRuntime(9896): ... 11 more
答案 0 :(得分：1)
在你的帖子中，尝试更改：
Intent DragonFruitActivityIntent = new Intent("main");
为：
Intent DragonFruitActivityIntent = new Intent(DragonFruitActivity.this, NameOfActivityToStart.class);
或者，如果您想更改布局而不是开始新活动，请删除：
Intent DragonFruitActivityIntent = new Intent("main");
startActivity(DragonFruitActivityIntent);
而是写：
DragonFruitActivity.this.setContentView(R.layout.main);
顺便说一句，如果不是在5秒钟内休眠，那么线程会做一些有用的事情，例如为你的应用加载一些数据 - 否则它只会减慢你对应用的访问速度。
修改：尝试将所有代码从onCreate（）移到onStart（），所以就像这样：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.splash);
}
@Override
public void onStart() {
super.onStart()
Thread logoTimer = new Thread() {
... // the rest of your code here
}
在完全形成之前，您可能会遇到访问用户界面的问题。
答案 1 :(得分：0)
正如你的日志猫所暗示的那样......
at com.Dragon_Fruit.DragonFruitActivity.onCreate(DragonFruitActivity.java:44)
您的DragonFruitActivity文件存在一些问题。在OnCreate回调中的第44行..
我想删除它可以解决NullpointerException的问题。