Android GridView-如何动态更改位图？

Question

您好，我有一个用于显示一些图片（不同级别的拇指）的图片。当用户完成一个级别时，我想更改该级别的拇指。 （以某种方式表明它已经完成）。

我为每个级别创建了两个大拇指。一个是原始的，一个表明该级别已完成。

但是如何更改图像的来源？

我用来绘制图像的代码看起来像这样。

主要活动：

/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.maps);

  GridView gridview = (GridView) findViewById(R.id.gridview);
  gridview.setAdapter(new ImageAdapter(this));

  gridview.setOnItemClickListener(new OnItemClickListener() {
    @Override
      public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
        //Open the map which was clicked on, if there is one
        if(position+1 > 1){
            Toast.makeText(maps.this, "Level " + (position+1) + " is not yet available!", Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(maps.this, "Opening Level " + (position+1), Toast.LENGTH_SHORT).show();
            Intent myIntent = new Intent(v.getContext(), Tutorial2D.class);
            startActivity(myIntent);
        }
      }
  });
}

ImageAdapter类：

public class ImageAdapter extends BaseAdapter {
private Context mContext;

public ImageAdapter(Context c) {
    mContext = c;
}

public int getCount() {
    return mThumbIds.length;
}

public Object getItem(int position) {
    return null;
}

public long getItemId(int position) {
    return 0;
}

// create a new ImageView for each item referenced by the Adapter
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;
    }

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



// references to our images
private Integer[] mThumbIds = {
        R.drawable.map1, R.drawable.map2, R.drawable.map3,
        R.drawable.map4, R.drawable.map5, R.drawable.map6,
        R.drawable.map7, R.drawable.map8, R.drawable.map9,
        R.drawable.map10, R.drawable.map11, R.drawable.map12,
        R.drawable.map13, R.drawable.map14, R.drawable.map15,
        R.drawable.map16, R.drawable.map17, R.drawable.map18,
        R.drawable.map19
};

}

Answer 1

您可以根据拇指创建一个新的位图，并使用画布绘制额外的图形。然后，您可以使用imageView.setimagebitmap将该位图传递给ImageView

编辑

就像是

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;
    }

    if (mLevelfinished) {

        //create thumbnail bitmap
        mThumbBmp = BitmapFactory.decodeResource(mResources, mThumbIds[position]);

        //draw a check over the bitmap
        Canvas c = new Canvas(mThumbBmp);
        c.drawBitmap(mCheckBitmap, destX, destY, null);

        imageView.setImageBitmap(mThumbBmp);
    } else {
        imageView.setImageResource(mThumbIds[position]);
    }

    return imageView;
}

edit2

我现在看到我有点误解了你的问题.. doh。与其动态地创建水平完整的拇指，不如为它们提供拇指。在这种情况下，我将创建另一个具有完成拇指的数组，并从正确的数组中选择资源。要坚持数组，也许也将级别的完成也存储在一起：

imageView.setImageResource((mLevelCompleted[position]) ? mThumbCompleteIds[position] : mThumbIds[position]);

Answer 2

我有同样的问题。这是我要做的：

gridview.setAdapter(new ImageAdapter(this));
gridview.setOnItemClickListener(new OnItemClickListener() {
  public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
    Toast.makeText(Punch.this, "" + mThumbIds[position], Toast.LENGTH_SHORT).show();
     mThumbIds[position]=R.drawable.crabx;//crabxImg;

  //here is where I would like to redraw the whole grid but it will not let me. 
  //Because ImageAdapter is not defined within this callback.

  }


})

Answer 3

我正在使用一个肮脏的技巧，当您以前知道将显示哪些位图时可能很有用。

我设置了另一个看不见的 ImageView 只是旁边可见，然后操纵

myImageView.setVisibility(n); // (n = 0 = View.VISIBLE) or (n = 8 = View.GONE)

不要使用常数 View.INVISIBLE 哪个值 4, ， 因为 View.GONE 是正确的效果。当可见性设置为 View.GONE, ，该对象不会在布局中占用空间。这类似于 display: none; 来自CSS。