Question

我正在尝试给布局的特定部分充气但是我遇到了编译错误，并且我不确定采取什么方法。特别是与行 -

LinearLayout childList = (LinearLayout)findViewById(R.id.listLayout). 
//(This can be found near the bottom of Java code.)

我也不确定在尝试给listLayout充气时是否采取了正确的方法。

在这个阶段，我试图在顶部设置一个按钮，然后动态地为其下面的数组中的项目列表充气。

非常感谢任何帮助

XML

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/labelAddCourseButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:onClick="addCourseButton"
        android:padding="10dp"
        android:text="@string/CourseName" />

    <LinearLayout
    android:id="@+id/listLayout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="horizontal" >     

    <TextView
        android:id="@+id/labelModuleCode"
        android:layout_height="wrap_content"
         android:layout_width="wrap_content"
         android:layout_marginLeft="10dp"
        android:text="@string/CourseName"
        android:textSize="10dp" />

     <TextView
        android:id="@+id/labelCourseType"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/CourseType"
        android:layout_marginLeft="10dp"
        android:textSize="10dp" />

    </LinearLayout>

</LinearLayout>

爪哇

package com.example.mycoursetimetable;

import android.os.Bundle;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;

public class MyCourses extends ListActivity {

    static final String TEST = "com.example.mycoursetimetable.TEST";
    String [] MODULE;

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my_courses);
        MODULE = getResources().getStringArray(R.array.module);
        setListAdapter(new ListArrayAdapter(this,MODULE));
    }

    public void addCourseButton (View addCourseButton) 
    {
        Intent intent = new Intent(this,AddCourse.class);
        startActivity(intent);
    }

    public void onListItemClick(ListView l, View v, int position, long id)
    {
        super.onListItemClick(l, v, position, id);

        try {
        Class test = Class.forName("com.example.MyCourseTimeTable.AddCourse");
        Intent intent = new Intent(MyCourses.this, test);

        TextView textView = (TextView) v.findViewById(R.id.labelModuleCode);
        String module = textView.getText().toString();

        intent.putExtra(TEST,module);
        startActivity(intent);
        }   
        catch (ClassNotFoundException e)
        {
        e.printStackTrace();
        }             
    }    
}

class ListArrayAdapter extends ArrayAdapter<String> 
{
    //Context allows the retrieval of resources such as layout
    private final Context context;
    private final String[] test;

    //create the ArrayAdpater
    public ListArrayAdapter(Context context, String[] test) 
    {
        super(context, R.layout.activity_my_courses, test);
        this.context = context;
        this.test = test;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) 
    {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        //inflater  dynamically loads the layout

        LinearLayout childList = (LinearLayout)findViewById(R.id.listLayout);
        View rowView = inflater.inflate(R.layout.childList, parent, false);

        //get the textView
        TextView textView = (TextView) rowView.findViewById(R.id.labelModuleCode);
        //set the text to the string values based on position
        textView.setText(test[position]);

        // Change item based on its position in the string array
        String modulePosition = test[position];             

        //return the layout
        return rowView;
    }
}

Answer 1

尝试将getView()修改为以下版本：

       @Override
        public View getView(int position, View convertView, ViewGroup parent) 
        {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
      //inflater  dynamically loads the layout

        LinearLayout childList = (LinearLayout)findViewById(R.id.listLayout);
        convertView = inflater.inflate(R.layout.childList, null);

        //get the textView
        TextView textView = (TextView) convertView.findViewById(R.id.labelModuleCode);
        //set the text to the string values based on position
        textView.setText(test[position]);

        // Change item based on its position in the string array
        String modulePosition = test[position];



        //return the layout
        return convertView;
        }

使用getView()的{{1}}视图而不是您自己的convertView。

Answer 2

以下是您可能需要的示例。通过观看Android的Romain Guy discuss adapters and efficiency来了解我使用ViewHolder和其他技巧的原因：

class ListArrayAdapter extends ArrayAdapter<String> 
{
    //  You only need one copy of LayoutInflater
    private final LayoutInflater inflater;

    //create the ArrayAdpater
    public ListArrayAdapter(Context context, String[] test) 
    {
        // The layout here doesn't really matter since we don't use it
        super(context, R.layout.childList, test);
        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) 
    {
        ViewHolder holder;
        if(convertView == null) {
            // Inflate the layout that you want for each row
            convertView = inflater.inflate(R.layout.childList, parent, false);

            holder = new ViewHolder();
            holder.code = (TextView) convertView.findViewById(R.id.labelModuleCode);
            holder.type = (TextView) convertView.findViewById(R.id.labelModuleType);

            // Add a reference in ViewHolder for your Button, find it like the TextViews and define its OnClickListener here too, eventually...

            convertView.setTag(holder);
        }
        else 
            holder = (ViewHolder) convertView.getTag();

        String module = getItem(position);
        //set the text to the string values based on position
        holder.code.setText(module);

        //return the layout
        return convertView;
    }

    class ViewHolder {
        TextView code;
        TextView type;
    }
}

如何给儿童观点充气？

2 个答案: