Question

我尝试创建使用声音的应用程序。我遵循了本教程：https://www.youtube.com/watch?v=Fg7ib6S7ZkA。我创建了一个应用程序，它构建成功，没有错误，但是当我尝试在模拟器或设备上使用它时它崩溃了，只有消息“不幸'app_name'已停止”

我发现启动MediaPlayer变量 mpSplash.start(); 时出现问题，因为当我评论此行时，一切正常（没有启动声音）

代码：

package com.example.nowa;

import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash);

        MediaPlayer mpSplash = MediaPlayer.create(this,R.raw.soo);
        mpSplash.start();


        Thread logoTimer = new Thread(){
            public void run() {
                try{
                    int logoTimer = 0;
                    while (logoTimer <5000){
                        sleep(100);
                        logoTimer = logoTimer + 100;
                    }
                    startActivity(new Intent("com.example.nowa.CLEARSCREEN"));
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                finally{
                    finish();
                }   

            }

        };

    logoTimer.start();


    }



}

第2次活动

package com.example.nowa;

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

公共类myMenu扩展了Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);


    setContentView(R.layout.fragment_main);
}

}

清单：

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

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.nowa.MainActivity"
            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="com.example.nowa.myMenu"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="com.example.nowa.CLEARSCREEN" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>


    </application>

</manifest>

Logcat信息：

05-05 17:25:57.626: E/MediaPlayer(638): error (1, -2147483648)
05-05 17:25:57.676: E/AndroidRuntime(638): FATAL EXCEPTION: main
05-05 17:25:57.676: E/AndroidRuntime(638): Process: com.example.nowa, PID: 638
05-05 17:25:57.676: E/AndroidRuntime(638): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.nowa/com.example.nowa.MainActivity}: java.lang.NullPointerException
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2208)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2270)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread.access$800(ActivityThread.java:138)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1209)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.os.Handler.dispatchMessage(Handler.java:102)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.os.Looper.loop(Looper.java:136)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread.main(ActivityThread.java:5042)
05-05 17:25:57.676: E/AndroidRuntime(638):  at java.lang.reflect.Method.invokeNative(Native Method)
05-05 17:25:57.676: E/AndroidRuntime(638):  at java.lang.reflect.Method.invoke(Method.java:515)
05-05 17:25:57.676: E/AndroidRuntime(638):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:776)
05-05 17:25:57.676: E/AndroidRuntime(638):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
05-05 17:25:57.676: E/AndroidRuntime(638):  at dalvik.system.NativeStart.main(Native Method)
05-05 17:25:57.676: E/AndroidRuntime(638): Caused by: java.lang.NullPointerException
05-05 17:25:57.676: E/AndroidRuntime(638):  at com.example.nowa.MainActivity.onCreate(MainActivity.java:28)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.Activity.performCreate(Activity.java:5231)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-05 17:25:57.676: E/AndroidRuntime(638):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2172)
05-05 17:25:57.676: E/AndroidRuntime(638):  ... 11 more

使用带有MediaPlayer变量的start（）时出现问题

0 个答案: