Question

我想随机化将从数据库中提取的背面图像（代码仍未添加），但我写的代码不起作用。我原本刚刚添加了翻转功能。我搜索了如何随机化图像并尝试按照给出的代码。可悲的是，它不适合我。

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

    // get references to the imageView objects
    imgUpperLeft = (ImageView) findViewById(R.id.imgUpperLeft);
    imgUpperRight = (ImageView) findViewById(R.id.imageView2);
    imgLowerLeft = (ImageView) findViewById(R.id.imageView3);
    imgLowerRight = (ImageView) findViewById(R.id.imageView4);

    // Setting the initial image (First face of cards)
    imgUpperLeft.setImageResource(R.drawable.img_waterfall);
    imgUpperRight.setImageResource(R.drawable.img_waterfall);
    imgLowerLeft.setImageResource(R.drawable.img_waterfall);
    imgLowerRight.setImageResource(R.drawable.img_waterfall);

    imgUpperLeft.setVisibility(View.VISIBLE);
    imgUpperRight.setVisibility(View.VISIBLE);
    imgLowerLeft.setVisibility(View.VISIBLE);
    imgLowerRight.setVisibility(View.VISIBLE);


}


ImageView imgView = new ImageView(this);
Random rand = new Random();
int rndInt = rand.nextInt(4) + 1; // n = the number of images, that start at idx 1
String imgName = "img" + rndInt;
int id = getResources().getIdentifier(imgName, "drawable", getPackageName());

// Shows the second face of the cards

public void showUpperLeftImage(View v){
    imgView.setImageResource(id);
}
public void showUpperRightImage(View v){
    imgView.setImageResource(id);
}
public void showLowerLeftImage(View v){

    imgView.setImageResource(id);
}
public void showLowerRightImage(View v){
    imgView.setImageResource(id);
}

Answer 1

代码中的两件事对我来说很突出：

ImageView imgView = new ImageView(this);

此ImageView不是视图层次结构的一部分，这意味着它不在屏幕上。屏幕上有没有意味着什么？如果没有，那么我认为你不需要这个。

public void showUpperLeftImage(View v){
    imgView.setImageResource(id);
}

您有四种方法可以更改不在屏幕上的视图图像。根据他们的方法名称来判断，我想您想要使用findViewById()更改之前找到的四个ImageView的图像。

我想你想这样做：

public void showUpperLeftImage(int id) {
    imgUpperLeft.setImageResource(id);
}
public void showUpperRightImage(int id) {
    imgUpperRight.setImageResource(id);
}
public void showLowerLeftImage(int id) {
    imgLowerLeft.setImageResource(id);
}
public void showLowerRightImage(int id) {
    imgLowerRight.setImageResource(id);
}

如何在android studio中随机化图像？我写的代码不起作用

1 个答案: