以编程方式覆盖图像

问题描述：

我正在尝试使用图像，透明渐变叠加和textView来实现一个gridView，因此无论图像的颜色如何，文本总是可读的。我无法添加叠加层和TextView。我在另一个问题中读到，RelativeLayouts是叠加的方式，然后为渐变XML文件设置RelativeLayout背景。这是我到目前为止。以编程方式覆盖图像

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 
    }; 
}

这是梯度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>

不能使用谷歌？ –

这是一个很常见的问题 –

发布您的XML布局，这是一个z顺序问题 – bonnyz

答

为了改变基于XML-Z顺序，只需调用方法bringToFront()

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

以编程方式覆盖图像

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