Question

我正在尝试使用KitKat上随机生成的颜色创建ListView 问题：它只显示不同项目的相同颜色这是我的代码：

Drawable d = getResources().getDrawable(R.drawable.main_item_image_background);
        int r = (int) (Math.random() * 256);
        int g = (int) (Math.random() * 256);
        int b = (int) (Math.random() * 256);

        int randColor = Color.argb(255, r, g, b);

        d.setColorFilter(new PorterDuffColorFilter(randColor, PorterDuff.Mode.SRC_IN));
        viewHolder.ivLogoBackground.setImageDrawable(d);

我也试过这样做：

Random rand = new Random();
int r = rand.nextInt(256);
int g = rand.nextInt(256);
int b = rand.nextInt(256);

它在Lollipop或更高版本上运行良好但在KitKat上它显示每个项目的相同颜色。我认为问题出在d.setColorFilter(new PorterDuffColorFilter(randColor, PorterDuff.Mode.SRC_IN));

Android M：

Android KitKat： KitKat

解决方案： Drawable必须采用mutate()方法。然后列表项中的图像将是不同的颜色：）

Answer 1

///适配器类

public class TestAdapter extends RecyclerView.Adapter<TestAdapter.CustomViewHolder> {
private ColorGenerator generator;
private Activity mActivity;
private ArrayList<String> iDataList;
public TestAdapter(Activity activity, ArrayList<String> countryList, int limit, boolean isLiveCountry) {
    this.mActivity = activity;
    generator = ColorGenerator.MATERIAL;
}

@Override
public CustomViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_item, parent, false);
    return new CustomViewHolder(view);
}

@Override
public void onBindViewHolder(CustomViewHolder holder, final int position) {

    int color = generator.getRandomColor();
    holder.view.setBackgroundColor(color);
}

@Override
public int getItemCount() {
    return iDataList.size();

}
public class CustomViewHolder extends RecyclerView.ViewHolder {
    private View view;

    public CustomViewHolder(View itemView) {
        super(itemView);
        view =  itemView.findViewById(R.id.view);
    }
}

}

//颜色生成器

public class ColorGenerator {
public static ColorGenerator DEFAULT;

public static ColorGenerator MATERIAL;

static {
    DEFAULT = create(Arrays.asList(
            0xfff16364,
            0xfff58559,
            0xfff9a43e,
            0xffe4c62e,
            0xff67bf74,
            0xff59a2be,
            0xff2093cd,
            0xffad62a7,
            0xff805781
    ));
    MATERIAL = create(Arrays.asList(
            0xffe57373,
            0xfff06292,
            0xffba68c8,
            0xff9575cd,
            0xff7986cb,
            0xff64b5f6,
            0xff4fc3f7,
            0xff4dd0e1,
            0xff4db6ac,
            0xff81c784,
            0xffaed581,
            0xffff8a65,
            0xffd4e157,
            0xffffd54f,
            0xffffb74d,
            0xffa1887f,
            0xff90a4ae
    ));
}

private final List<Integer> mColors;
private final Random mRandom;

public static ColorGenerator create(List<Integer> colorList) {
    return new ColorGenerator(colorList);
}

private ColorGenerator(List<Integer> colorList) {
    mColors = colorList;
    mRandom = new Random(System.currentTimeMillis());
}

public int getRandomColor() {
    return mColors.get(mRandom.nextInt(mColors.size()));
}

public int getColor(Object key) {
    return mColors.get(Math.abs(key.hashCode()) % mColors.size());
}

如何在KitKat上创建具有随机颜色的ListView项目

1 个答案: