Question

我试图在Overriding＆＃34; layoutChildren（）＆＃34;的基础上改变GridView列大小。但是当我打电话给服装类时，它会抛出异常这是来自＆＃34; Getview＆＃34;的调用代码。在我的适配器类中：

public View getView (int position, View convertView, ViewGroup parent) 
{
    mParentView = parent;

    ImageCell v = null;
    if (convertView == null) {
        v = new ImageCell (mContext);
        v.setLayoutParams(new ResizeableGridView.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        v.setScaleType(ImageView.ScaleType.CENTER_CROP);
        v.setPadding(40, 40, 40, 40);

    } else {
        v = (ImageCell) convertView;
    }

    v.mCellNumber = position;
    v.mGrid = (ResizeableGridView) mParentView;
    v.mEmpty = true;
    v.setBackgroundResource (R.color.cell_empty);
started.
    v.setOnTouchListener ((View.OnTouchListener) mContext);
    v.setOnClickListener ((View.OnClickListener) mContext);
    v.setOnLongClickListener ((View.OnLongClickListener) mContext);

    return v;
}

和＆＃34; ResizeableGridView＆＃34; ：

package com.package.mypackage;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.GridView;

public class ResizeableGridView extends GridView {

private int height;

public ResizeableGridView(Context context) {
    super(context);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     height = getHeight();
}

@Override
protected void layoutChildren() {
    super.layoutChildren();
    View v = getChildAt(0);
    if((v.getHeight()*5) < height){
        //if the combined height of rows is less than parent then only resize the children to fit parent
        int count = getChildCount();
        for(int i = 0;i < count;i++){
            View view = getChildAt(i);
            ViewGroup.LayoutParams params = view.getLayoutParams();
            //I am using 5 because i used it for calendar and it has exactly five rows
            params.height = height/5;
            view.setLayoutParams(params);
        }//end for
    }//end if
 } // end layoutChildren
}

来自logcat的错误日志：

12-20 10:40:41.382: E/AndroidRuntime(2646): FATAL EXCEPTION: main
12-20 10:40:41.382: E/AndroidRuntime(2646): java.lang.ClassCastException: android.widget.GridView
12-20 10:40:41.382: E/AndroidRuntime(2646):     at com.package.mypackage.ImageCellAdapter.getView(ImageCellAdapter.java:81)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.AbsListView.obtainView(AbsListView.java:1592)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.GridView.onMeasure(GridView.java:955)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.View.measure(View.java:8313)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:386)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.View.measure(View.java:8313)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:386)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.View.measure(View.java:8313)
12-20 10:40:41.382: E/AndroidRuntime(2646):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)

Answer 1

ViewGroup.LayoutParams params = view.getLayoutParams();这导致异常，您必须使用

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(your_height,your_width);
convertView.setLayoutParams(new GridView.LayoutParams(params));

如果容器是LinearLayout

调用扩展的gridview类会引发异常

1 个答案: