我使用共享首选项对象保存用户的数据，然后将该数据复制到HashMap对象中。将数据复制到Hasmap对象后，我使用Arraylist对象在ListView中显示我的所有数据。
当我仅使用Textview而不是ListView进行测试时，它可以正常工作。我可以显示数据，但它只显示一条记录（键/值对）。我想使用ListView，以便显示存储在共享首选项对象中的所有数据。
下面是将数据从共享首选项对象复制到HashMap然后使用arrraylist在ListView上显示它的类：
public class DisplayMyTestsActivity extends Activity {
String STName;
TextView STNameTextView, STValueTextView;
ListView STListView;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.displaymytests);
//Use SharedPreferences to save the key/value pairs
SharedPreferences sharedPref = getSharedPreferences("STData", Context.MODE_PRIVATE);
//save "special test name" in String 'testName'
String testName = sharedPref.getString("specialTestName", STName);
//save special test Value in String 'testValue'
boolean testValue = sharedPref.getBoolean("specialTestValue", false);
//save the boolean value in a String so that it can be displayed on an edit text
String testValueStr = String.valueOf(testValue);
//here I tested if I can display my data on a textView instead of a ListView and it works
// Display the Name of the Special Test on a TextView
STNameTextView = (TextView) findViewById(R.id.STNameView1);
STNameTextView.setText(testName);
//Display the Value (positive or negative) of the Special Test on a TextView
STValueTextView = (TextView) findViewById(R.id.STValueView1);
STValueTextView.setText(testValueStr);
//to edit the data or add data inside my file "STData"
SharedPreferences.Editor editor = sharedPref.edit();
//Define a HashMap object
Map<String, String> map = new HashMap<String, String>();
//Store key/value pair data from shared pref in HashMap object
for (Map.Entry<String, String> entry : map.entrySet())
{
editor.putString(entry.getKey(), entry.getValue());
editor.commit();
}
//Pass hashmap object "map" to adapter
//MyAdapter constructor creates an ArrayList then adds all the data in map to the ArrayList
//The object "adapter" is now an arraylist that contains all the hashmap data (I created a seperate adapter class)
MyAdapter adapter = new MyAdapter(map);
//Point to the listView where data to be displayed - in layout file (displaymytests)
STListView = (ListView) findViewById(R.id.ST_ListView);
//Populate the listView with the data from The ArrayList ('adapter')
STListView.setAdapter(adapter);
}
}
这是我的适配器类：
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.Map;
public class MyAdapter extends BaseAdapter {
private final ArrayList mData;
public MyAdapter(Map<String, String> map) {
mData = new ArrayList();
mData.addAll(map.entrySet());
}
@Override
public int getCount() {
return mData.size();
}
@Override
public Map.Entry<String, String> getItem(int position) {
return (Map.Entry) mData.get(position);
}
@Override
public long getItemId(int position) {
// TODO implement you own logic with ID
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final View result;
if (convertView == null) {
result = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_adapter_item, parent, false);
} else {
result = convertView;
}
Map.Entry<String, String> item = getItem(position);
// TODO replace findViewById by ViewHolder
((TextView) result.findViewById(android.R.id.text1)).setText(item.getKey());
((TextView) result.findViewById(android.R.id.text2)).setText(item.getValue());
return result;
}
}
这是我的布局文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:weightSum="1"
android:orientation="vertical">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_weight="0.06">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="STName"
android:id="@+id/STNameView1"
android:layout_marginTop="20dp"
android:layout_marginLeft="40dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="STValue"
android:id="@+id/STValueView1"
android:layout_marginLeft="140dp"
android:layout_marginTop="20dp" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_weight="0.94">
<ListView
android:layout_width="wrap_content"
android:layout_height="387dp"
android:id="@+id/ST_ListView" />
</LinearLayout>
</LinearLayout>
我修改了我的代码如下，但仍然给出了错误：“此行不兼容的错误”map = sharedPref.getAll（）;“”
//Define a HashMap object
Map<String, String> map = new HashMap<String, String>();
// Store key/value pair data from shared pref in HashMap object
map = sharedPref.getAll();
//Retrieve the the keys with keySet() and the key/value mappings with entrySet()
for (Map.Entry<String, ?> entry : map.entrySet())
for (Map.Entry<String, String> entry : map.entrySet())
{
editor.putString(entry.getKey(), entry.getValue());
editor.commit();
}
FYI，getAll（）返回一个Map（String，？）类型的对象，但我的是Map（String，String）b / c我需要将它传递给 MyAdapter ，并且应该是类型Map（String，String）
答案 0 :(得分：1)
现在您正在创建一个空Map并将其用于适配器。因此，map.entrySet()上的循环永远不会执行，并且您有一个空列表。
SharedPreferences有一个名为getAll()的方法，可将您的偏好设置为Map。你可能只能使用它。