我正在尝试按照本指南创建具有两种不同布局的 ListView 来为设置菜单创建 Activity ,但有些部分对我来说不明确,我的尝试没有奏效。 http://android.amberfog.com/?p=296
activity_settings.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.austin.kanadrill.SettingsActivity">
<ListView
android:id="@+id/settingsListView"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</RelativeLayout>
设置 Activity .java
package com.example.austin.kanadrill;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
public class SettingsActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_settings);
ListView settingsListView = findViewById(R.id.settingsListView);
SettingsAdapter settingsAdapter = new SettingsAdapter();
settingsAdapter.addItem("Hiragana");
settingsAdapter.addItem("Katakana");
settingsAdapter.addItem("Fonts");
settingsAdapter.addCheckBoxItem("Speed Mode");
settingsListView.setAdapter(settingsAdapter);
}
}
设置适配器.java
package com.example.austin.kanadrill;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.TreeSet;
public class SettingsAdapter extends BaseAdapter {
final int TYPE_ITEM = 0;
final int TYPE_CHECKBOX_ITEM = 1;
final int TYPE_MAX_COUNT = 2;
Context ctx;
ArrayList mData = new ArrayList();
LayoutInflater mInflator;
TreeSet mCheckBoxSet = new TreeSet();
public SettingsAdapter() {
mInflator = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}
public void addCheckBoxItem(final String item) {
mData.add(item);
mCheckBoxSet.add(mData.size()-1);
notifyDataSetChanged();
}
@Override
public int getItemViewType(int position) {
return mCheckBoxSet.contains(position) ? TYPE_CHECKBOX_ITEM : TYPE_ITEM;
}
@Override
public int getViewTypeCount() {
return TYPE_MAX_COUNT;
}
@Override
public int getCount() {
return mData.size();
}
@Override
public String getItem(int position) {
return (String) mData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int type = getItemViewType(position);
if(convertView == null) {
holder = new ViewHolder();
switch(type) {
case TYPE_ITEM:
convertView = mInflator.inflate(android.R.layout.simple_list_item_1, null);
holder.textView = (TextView) convertView.findViewById(R.id.settingsListView);
break;
case TYPE_CHECKBOX_ITEM:
convertView = mInflator.inflate(android.R.layout.simple_list_item_multiple_choice, null);
holder.textView = (TextView) convertView.findViewById(R.id.settingsListView);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textView.setText((String)mData.get(position));
return convertView;
}
private static class ViewHolder {
public TextView textView;
}
}
我遇到了一些问题,尤其是在 SettingsAdapter 的构造函数中,因为我认为我需要创建一个上下文来调用 getSystemService() 并且我怀疑我是否正确地做到了这一点。我也不明白在 getView() 中到底要做什么,所以这也可能是错误的。我的目标是只有一个 ListView,其中前三个字符串是 simple_list_item_1,第四个字符串是 simple_list_item_multiple_choice。我怎样才能修复这段代码来完成它,或者只是从头开始? 谢谢。
最佳答案
你的代码有两个问题
将 Activity 上下文传递给 Settings Apdapter,它必须抛出异常。
SettingsActivity.java
SettingsAdapter settingsAdapter = new SettingsAdapter(this);
SettingsAdpater.java
public SettingsAdapter(Context context) {
ctx = context
mInflator = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
对于 textview id,使用 android.R.id.text1
(这是在 R.layout.simple_list_item_1
和 android.R.layout 中定义的 id .simple_list_item_multiple_choice
)
switch(type) {
case TYPE_ITEM:
convertView = mInflator.inflate(android.R.layout.simple_list_item_1, null);
holder.textView = (TextView) convertView.findViewById(android.R.id.text1);
break;
case TYPE_CHECKBOX_ITEM:
convertView = mInflator.inflate(android.R.layout.simple_list_item_multiple_choice, null);
holder.textView = (TextView) convertView.findViewById(android.R.id.text1);
break;
}
如果您不明白任何部分,请告诉我,我们很乐意提供帮助。
关于java - 在 Android 上创建一个包含 simple_list_item_1 和 simple_list_item_multiple_choice 的 ListView,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50691401/