加载和滚动时 Listview 行颜色混合

Question

我正在根据其中一个子项的文本值设置行的背景颜色。但是，无论其文本值如何，都会设置多个背景。上下滚动时会变得更糟。适配器代码：

package com.test.app;

import java.util.ArrayList;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MyBaseAdapter extends BaseAdapter {

    private LayoutInflater mInflater = null;
    private ArrayList<String[]> mItems = new ArrayList<String[]>();

    public MyBaseAdapter(Context context, ArrayList<String[]> items) {
         mItems = items;
         mInflater = LayoutInflater.from(context);
    }

    public void addItem(String[] it) {
        mItems.add(it);
    }

    public void setListItems(ArrayList<String[]> lit) {
        mItems = lit;
    }

    @Override
    public int getCount() {
        return mItems.size();
    }

    @Override
    public Object getItem(int position) {
        return mItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    static class ViewHolder {
        public TextView tv0,tv1;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        View rowView = null;
        ViewHolder viewHolder;

        if(convertView == null)
        {
            rowView = mInflater.inflate(R.layout.history_row, null);
        }
        else
        {
            rowView = convertView;
        }

        viewHolder = new ViewHolder();

        viewHolder.tv0 = (TextView)rowView.findViewById(R.id.textView0);
        viewHolder.tv1 = (TextView)rowView.findViewById(R.id.textView1);

        rowView.setTag(viewHolder);

        ViewHolder holder = (ViewHolder) rowView.getTag();

        holder.tv0.setText(mItems.get(position)[0].toString());
        holder.tv1.setText(mItems.get(position)[1].toString());

        if(holder.tv1.getText().equals("0"))
        {
            rowView.setBackgroundColor(0xAA777777);
            // Only the row containing "0" should be colored, yet it colors multiple, random rows.
        }

        return rowView;
    }

}

Answer 1

如果你只是使用：

if(holder.tv1.getText().equals("0")) {
            rowView.setBackgroundColor(0xAA777777);
            // Only the row containing "0" should be colored, yet it colors multiple, random  rows.
}

这确实会使包含0 的行具有特定的颜色，但是当您上下滚动列表时，具有这种颜色的特定行将被回收并最终出现在不应该出现的地方。正确的方法是为不包含 0 的行提供默认颜色，以便覆盖可能回收视图的错误颜色：

if(holder.tv1.getText().equals("0")) {
            rowView.setBackgroundColor(0xAA777777);
            // Only the row containing "0" should be colored, yet it colors multiple, random  rows.
} else {
   rowView.setBackgroundColor(/*Here the default color will be*/)
   // This row doesn't contain 0 so it must have the default color.
  // Because you could be dealing with a recycled view(that has the above color)
 // then we must revert the color to the default to be sure we end up with the correct color.
}

ViewHolder 模式的正确代码是：

    View rowView = convertView;
    ViewHolder viewHolder;

    if(rowView == null) {
        rowView = mInflater.inflate(R.layout.history_row, parent, false);
        viewHolder = new ViewHolder();
        viewHolder.tv0 = (TextView)rowView.findViewById(R.id.textView0);
        viewHolder.tv1 = (TextView)rowView.findViewById(R.id.textView1);
        rowView.setTag(viewHolder);
    } else {
        viewHolder = (ViewHolder) rowView.getTag();    
    }             

然后您使用viewHolder 对象来设置行的数据。

Answer 2

你可以试试，设置成ListView：android:cacheColorHint="#00000000"