播放按鈕上的聲音無法啓動

Question

我試圖製作一個應用程序，播放聲音時按鈕單擊和我喜歡100 +聲音和100 +按鈕。我已經創建了按鈕，現在將它映射到要播放的聲音。另一件事，當點擊超過「x」次數時，mediaplayer崩潰。任何想法如何解決？

注意：代碼不想執行，因爲它是現在，我真的不明白爲什麼。

package com.example.buttonsdemo; 

import android.media.MediaPlayer; 
import android.os.Bundle; 
import android.app.Activity; 
import android.support.v4.widget.SimpleCursorAdapter.ViewBinder; 
import android.util.Log; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.Toast; 

public class MainActivity extends Activity implements View.OnClickListener { 

    // Creating Sound arrays 
    int i = 0; 
    MediaPlayer[] mediaplayer = new MediaPlayer[120]; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     for (int z = 0; z < 121; z++) { 
      mediaplayer[z] = null; 
     } 

     // Creating Button Array 
     Button button[] = new Button[120]; 
     for (int x = 0; x < 121; x++) { 
      button[x] = null; 
      button[x].setOnClickListener(this); 
     } 

     // Creating Media player array 

     mediaplayer[1] = MediaPlayer.create(this, R.raw.alistar); 
     mediaplayer[0] = MediaPlayer.create(this, R.raw.akali); 

     button[i].setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       switch (v.getId()) { 
       case R.id.akali: 
        i = 0; 
        break; 
       case R.id.alistar: 
        i = 1; 
        break; 
       } 
       mediaplayer[i].start(); 
      } 
     }); 
    } 

    @Override 
    public void onClick(View v) { 
     // TODO Auto-generated method stub 
    } 
} 

的logcat：

03-05 01:10:34.674: E/AndroidRuntime(1541): FATAL EXCEPTION: main 
03-05 01:10:34.674: E/AndroidRuntime(1541): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.buttonsdemo/com.example.buttonsdemo.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=120; index=120 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread.access$600(ActivityThread.java:141) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.os.Handler.dispatchMessage(Handler.java:99) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.os.Looper.loop(Looper.java:137) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at java.lang.reflect.Method.invokeNative(Native Method) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at java.lang.reflect.Method.invoke(Method.java:511) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at dalvik.system.NativeStart.main(Native Method) 
03-05 01:10:34.674: E/AndroidRuntime(1541): Caused by: java.lang.ArrayIndexOutOfBoundsException: length=120; index=120 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at com.example.buttonsdemo.MainActivity.onCreate(MainActivity.java:28) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.Activity.performCreate(Activity.java:5104) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
03-05 01:10:34.674: E/AndroidRuntime(1541):  ... 11 more 

Answer 1

您初始化數組。但是你錯過了其內容的初始化。

在你的循環，你需要把

button[x]= new Button(this); 
button[x].setOnClickListener(this); 

也正在使用變量i你初始化之前。

但現在我想到了，您實際需要做的是刷新MediaPlayer文檔。你真的不需要（也不想）擁有一個包含120個MediaPlayer對象的數組。來自documentation：

When done with the MediaPlayer, you should call release(), to free the resources. If not released, too many MediaPlayer instances will result in an exception.

您的最新版本有幾個錯誤。第一個錯誤：

for (int z = 0; z < 121; z++) { 
     mediaplayer[z] = null; 
    } 

因爲你的陣列有120元，你的條件必須是

for (int z = 0; z < 120; z++) { 
     mediaplayer[z] = null; 
    } 

第二個錯誤：你設置的按鈕數組元素爲空，然後您嘗試訪問他們

for(int x=0;x<120;x++){ 
    button[x]=new Button(this); 
    button[x].setOnClickListener(this); 
}