Question

我正在尝试使用图像，透明渐变叠加层和textView来实现gridView，因此无论图像颜色是什么，文本都将始终可读。我无法添加叠加层和TextView。我在另一个问题中读到，RelativeLayouts是覆盖的方法，然后为渐变XML文件设置RelativeLayout背景。这是我到目前为止所拥有的。

public class GridViewAdapter extends BaseAdapter {
    private Context mContext;

    public GridViewAdapter(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;
        RelativeLayout gradient;
        TextView textView;
        DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
        int screenWidth = metrics.widthPixels;
        if (convertView == null) {
            // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(screenWidth / 2, screenWidth / 2));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            gradient = new RelativeLayout(mContext);
            gradient.setBackground(mContext.getResources().getDrawable(R.drawable.gridview_gradient_image_overlay));
            gradient.setLayoutParams(new GridView.LayoutParams(screenWidth / 2, screenWidth / 2));

        } else {
            imageView = (ImageView) convertView;
            gradient = (RelativeLayout) convertView;
        }

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

    // references to images
    private Integer[] mThumbIds = {
            R.drawable.dog, R.drawable.cat,
            R.drawable.horse, R.drawable.bunny,
            R.drawable.fish, R.drawable.hamster,
            R.drawable.hedgehog, R.drawable.bird,
            R.drawable.turtle, R.drawable.goat
    };
}

这是渐变XML文件：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <gradient
        android:startColor="#33000000"
        android:centerColor="#11000000"
        android:endColor="#00000000"
        android:angle="90"
        android:dither="true"
        />
</shape>

XML布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rlGradient"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/gridview_gradient_image_overlay">

    <TextView
        android:id="@+id/tvGridViewAnimal"
        android:layout_width="10dp"
        android:layout_height="10dp"
        android:textColor="#ffffff"/>

</RelativeLayout>

Answer 1

要更改基于XML的z顺序，只需调用方法bringToFront()

即可

// create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
    //...
    textView.bringToFront();
    return imageView;
}

以编程方式叠加图像

1 个答案: