Android中的随机图像？

Question

我想用随机图像制作视图。我有代码，没有错误，但当我点击按钮去随机图像，它只是保持不变。

我的来源是：

private static final Random rgenerator = new Random(); 

private static final Integer[] mImageIds = 
    { R.drawable.img2, R.drawable.img1, R.drawable.img3, }; 

@Override 
public void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Integer q = mImageIds[rgenerator.nextInt(mImageIds.length)]; 
    ImageView iv = (ImageView) findViewById(R.id.imageviewyeah); 
    iv.setTag(q); 

    View nextButton = findViewById(R.id.next_image_button); 
    nextButton.setOnClickListener(this); 
} 

public void onClick(View v) 
{ 
    switch (v.getId()) 
    { 
     case R.id.next_image_button: 
      Intent i = new Intent(this, RandomImage.class); 
      startActivity(i); 
      break; 
    } 
} 

Answer 1

参考只要保持你的ImageView并调用setImageResource(int id)与随机的资源之一。你并不需要启动一个新的Activity检索随机资源ID ...

@Override 
public void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Integer q = mImageIds[rgenerator.nextInt(mImageIds.length)]; 
    final ImageView iv = (ImageView) findViewById(R.id.imageviewyeah); 

    View nextButton = findViewById(R.id.next_image_button); 
    nextButton.setOnClickListener(new OnClickListener() { 
     public void onClick(View V) { 
       int resource = mImageIds[rgenerator.nextInt(mImageIds.length)]; 
       iv.setImageResource(resource); 
     } 
    }); 
} 

Answer 2

我会改变一些事情。

private static final Random rgenerator = new Random(); 
private ImageView iv; 

private static final Integer[] mImageIds = 
    { R.drawable.img2, R.drawable.img1, R.drawable.img3, }; 

@Override 
public void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Integer q = mImageIds[rgenerator.nextInt(mImageIds.length)]; 
    iv = (ImageView) findViewById(R.id.imageviewyeah); 
    changeImageResource(); 

    View nextButton = findViewById(R.id.next_image_button); 
    nextButton.setOnClickListener(new OnClickListener() { 
     public void onClick(View v) { 
      changeImageResource(); 
     } 
    }); 
} 

public void changeImageResource() 
{ 
    int i = regeneratos.nextInt(3); 
    iv.setImageResource(mImageIds[i]); 
} 

希望这会有所帮助。