Android：在OnItemClick之后替换GridView数组中的图像

Question

我有一个看起来大致相同的网格视图（最后每个图像都是不同的）：

当用户点击数组中的任何图像时，我希望该图像更改为：

如果他们再次点击，则更改为：

然后再次点击将恢复为：

到目前为止，这是我的代码，只需使用Imageadapter创建一个GridView：

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

    GridView gridview = (GridView) findViewById(R.id.gridview);
    gridview.setAdapter(new ImageAdapter(this));
    gridview.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
            // CHANGE IMAGE HERE
            Toast.makeText(GridScroll.this, "" + position, Toast.LENGTH_SHORT).show();


        }
    });
}

}

和

    public View getView(int position, View convertView, ViewGroup parent) {
    ImageView imageView;
    if (convertView == null) {  // if it's not recycled, initialize some attributes
        imageView = new ImageView(mContext);
        imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8, 8, 8, 8);
    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageResource(mThumbIds[position]);
    return imageView;
}

// references to our images
private Integer[] mThumbIds = {
        R.drawable.lifestyle_5,R.drawable.lifestyle_6,
        R.drawable.lifestyle_7,R.drawable.lifestyle_8,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.lifestyle_1,R.drawable.lifestyle_2,
        R.drawable.lifestyle_3,R.drawable.lifestyle_4,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.lifestyle_1,R.drawable.lifestyle_2,
        R.drawable.lifestyle_3,R.drawable.lifestyle_4,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.lifestyle_1,R.drawable.lifestyle_2,
        R.drawable.lifestyle_3,R.drawable.lifestyle_4,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4,
        R.drawable.icon_4, R.drawable.icon_4, 
        R.drawable.icon_4, R.drawable.icon_4, 

};

Answer 1

要做到这一点，我们需要做两件事：

<强> 1。单击项目时更改项目的drawable。 在onItemClick(...)中，更改传递给您的View的drawable。此视图与您在适配器的getView(...)中创建的视图相同。

<强> 2。下次进入屏幕时，请确保该项目显示正确的drawable。 为此，请跟踪每个项目的状态。每次在getView(...)中查看项目时，请为其状态指定正确的drawable。

---

这是一个例子。我假设ImageAdapter是ArrayAdapter的子类。如果没有，那么您将需要修改此代码以使用您正在执行的操作。

把这些放在某处：

private static final int WHITE = 0;
private static final int TEAL = 1;
private static final int MAROON = 2;
private List<Integer> mStates = new ArrayList<Integer>();

这适用于您的ImageAdapter：

// Map each state to its graphics.
private Map<Integer, Integer> mStateResources = new HashMap<Integer, Integer>();
mStateResources.put(WHITE, R.drawable.white);

public void add(...) {
    super.add(...);

    // The new item will start as white.
    mStates.add(WHITE);
}

public View getView(int position, View convertView, ViewGroup parent) {
    //ImageView image = ...

    // Set the correct image for the state of this item.
    int state = mStates.get(position);
    int resId = mStateResources.get(state);
    image.setImageResource(resId);
}

在OnItemClickListener中：

public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
    // Change the image and state for this item.
    int nextState;
    switch(mStates.get(position)) {
    case WHITE:
        nextState = TEAL;
        break;
    case TEAL:
        nextState = MAROON;
        break;
    case MAROON:
        nextState = WHITE;
        break;
    }

    // Set the new state and image for this item.
    mStates.put(position, nextState);
    int resId = mStateResources.get(nextState);
    image.setImageResource(resId);
}