活动的随机xml布局文件

Question

我有五个布局（XML文件），每个布局有一个Button和两个活动，A & B.在A的开始按钮的onClick操作中，我将打开活动B和所有的故事开始出现：

在我的活动B，首先，我想说明这五个XML文件和Button在每五个XML文件的onclick之一，我想随意打开剩下的4个xml文件，直到按下返回按钮。。有什么办法可以做到这一点，或者我必须有5个活动，每个有一个布局？

我的问题是：

只是一个XML文件上的活动者B随机出现，并在该XML文件Button没有响应，即，没有出现下一个XML文件。

这里是我的活动B中的代码：

public class B extends Activity { 
Handler handler = new Handler(); 
Button bt; 

int[] layouts = {R.layout.first,R.layout.second,R.layout.third,R.layout.fourth,R.layout.fifth}; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 


    bt = (Button)findViewById(R.id.button1); 

    bt.setOnClickListener(new OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      // TODO Auto-generated method stub 

      handler.postDelayed(new Runnable() { 

       @Override 
       public void run() { 
        // TODO Auto-generated method stub 

        for (int i = 0; i < layouts.length; i++) { 


         setContentView(layouts[rand]); 
        } 

       } 
      }, 2000); 

     } 
    }); 


} 

而且所有的5 XML文件将走在相同的模式：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" 
tools:context=".MainActivity" > 

<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:gravity="center" 
    android:text="@string/hello_world" /> 

<Button 
    android:id="@+id/button5" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_gravity="center" 
    android:layout_marginTop="10dp" 
    android:onClick="showLayouts" 
    android:text="5th" /> 

我是新来的Java如此简单的线索也会帮助我。我搜索了这个论坛并没有找到相关的解决方案。

@LuksProg，logcat的错误是这样的：

**03-11 05:51:16.147: E/AndroidRuntime(1575): FATAL EXCEPTION: main 
03-11 05:51:16.147: E/AndroidRuntime(1575): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.SAI.wth/com.SAI.wth.ReceivingActivity}: java.lang.NullPointerException 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread.access$600(ActivityThread.java:141) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.os.Handler.dispatchMessage(Handler.java:99) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.os.Looper.loop(Looper.java:137) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread.main(ActivityThread.java:5039) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at java.lang.reflect.Method.invokeNative(Native Method) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at java.lang.reflect.Method.invoke(Method.java:511) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at dalvik.system.NativeStart.main(Native Method) 
03-11 05:51:16.147: E/AndroidRuntime(1575): Caused by: java.lang.NullPointerException 
03-11 05:51:16.147: E/AndroidRuntime(1575): at com.SAI.wth.ReceivingActivity.onCreate(ReceivingActivity.java:40) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.Activity.performCreate(Activity.java:5104) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
03-11 05:51:16.147: E/AndroidRuntime(1575): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)** 

这一次，我想这样做，

switch (mPosition) { 
          case R.layout.first: 
           Toast.makeText(getApplicationContext(), "First", Toast.LENGTH_SHORT).show(); 

           break; 

          case R.layout.second: 
           Toast.makeText(getApplicationContext(), "second", Toast.LENGTH_SHORT).show(); 
//Some sound         
           break; 

          case R.layout.third: 
           Toast.makeText(getApplicationContext(), "third", Toast.LENGTH_SHORT).show(); 
    //Some media , Different for each Layout..       
           break; 

          case R.layout.fourth: 
           Toast.makeText(getApplicationContext(), "fourth", Toast.LENGTH_SHORT).show(); 

           break; 

          case R.layout.fifth: 
           Toast.makeText(getApplicationContext(), "fifth", Toast.LENGTH_SHORT).show(); 

           break; 
          default: 
           break; 
          } 


          Collections.shuffle(mLayouts); 
         } 
         mPosition = 0; 
        } 

Answer 1

只是一个XML文件是否是随机浮出活动B &的按钮 该xml文件没有响应，即没有显示下一个xml文件。

你会想是这样的：

private int mPosition = 0; 
private Handler mHandler = new Handler(); 
private List<Integer> mLayouts; 
private Button mButton; 

private OnClickListener mListener = new OnClickListener() { 

    @Override 
    public void onClick(View v) { 
     mHandler.postDelayed(new Runnable() { 

      @Override 
      public void run() { 
       // as you're posting this delayed you may want to make sure the 
       // user doesn't click this Buton again in the two seconds interval 
       if (mPosition >= mLayouts.size()) { // revert the list 
        int lastId = mLayouts.get(mLayouts.size() - 1); 
        Collections.shuffle(mLayouts); 
        // do this so if we randomize the layouts we don't end 
        // up after the shuffle with the same layout on the 
        // first 
        // position as the last position 
        while (lastId == mLayouts.get(0)) { 
         Collections.shuffle(mLayouts); 
        } 
        mPosition = 0; 
       } 
       setContentView(mLayouts.get(mPosition)); 
       mPosition++; 
       mButton = (Button) findViewById(R.id.btnId); 
       mButton.setOnClickListener(mListener); 
      } 

     }, 2000);   
    } 

}; 

，并在onCreate方法：

mLayouts = new ArrayList<Integer>(); 
    mLayouts.add(R.layout.layout1); 
    mLayouts.add(R.layout.layout2); 
    mLayouts.add(R.layout.layout3); 
    mLayouts.add(R.layout.layout4); 
    mLayouts.add(R.layout.layout5); 
    Collections.shuffle(mLayouts); 
    setContentView(mLayouts.get(mPosition)); 
    mButton = (Button) findViewById(R.id.btnId); 
    mButton.setOnClickListener(mListener); 
    mPosition++; 

Answer 2

似乎当我做这个工作得很好：

public class MainActivity extends Activity implements OnClickListener { 
    Handler handler = new Handler(); 
    Button bt; 

    int[] layouts = { R.layout.first, R.layout.second, R.layout.third, R.layout.fourth, 
     R.layout.fifth }; 

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

     bt = (Button) findViewById(R.id.button5); 

     bt.setOnClickListener(this); 

    } 

    @Override 
    public void onClick(View v) { 
     if(v.getId() == R.id.button5){ 

      handler.postDelayed(new Runnable() { 

       @Override 
        public void run() { 
        // TODO Auto-generated method stub 
        int rand = (int) Math.floor(Math.random() * layouts.length); 
        setContentView(layouts[rand]); 


        bt = (Button) findViewById(R.id.button5); 
        bt.setOnClickListener(MainActivity.this); 

       } 
      }, 2000); 

     } 

    } 
}