我是Android的新手。我正在努力的一个问题是ArrayAdapter实施。阅读这么多教程，需要确保我正确理解它。
这是我尝试弄清楚它有多远：
package hfad.com.adapters;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends Activity {
//thorntech.com parsing jsonandroid using colley library
TextView results;
// URL of object to be parsed
String JsonURL = "https://raw.githubusercontent.com/ianbar20/JSON-Volley-Tutorial/master/Example-JSON-Files/Example-Array.JSON";
// This string will hold the results
String data = "";
// Defining the Volley request queue that handles the URL request concurrently
ListView myList;
RequestQueue requestQueue;
//Adding adapter and assign it -set- to a listview
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Creates the Volley request queue
requestQueue = Volley.newRequestQueue(this);
// Casts results into the TextView found within the main layout XML with id jsonData
results = (TextView) findViewById(R.id.textView);
myList = (ListView) findViewById(R.id.listv);
final ArrayAdapter myAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1);
ListView myList = (ListView) findViewById(R.id.listv);
myList.setAdapter(myAdapter);
// Creating the JsonArrayRequest class called arrayreq, passing the required parameters
//JsonURL is the URL to be fetched from
JsonArrayRequest arrayreq = new JsonArrayRequest(JsonURL,
// The second parameter Listener overrides the method onResponse() and passes
//JSONArray as a parameter
new Response.Listener<JSONArray>() {
// Takes the response from the JSON request
@Override
public void onResponse(JSONArray response) {
/* ================================================================== */
/* //////////////////////// Example using TextView and it works////////////////////// */
//url https://reqres.in/api/users?page=2
try {
// Retrieves first JSON object in outer array
JSONObject colorObj = response.getJSONObject(0);
// Retrieves "colorArray" from the JSON object
JSONArray colorArry = colorObj.getJSONArray("colorArray");
// Iterates through the JSON Array getting objects and adding them
//to the list view until there are no more objects in colorArray
for (int i = 0; i < colorArry.length(); i++) {
//gets each JSON object within the JSON array
JSONObject jsonObject = colorArry.getJSONObject(i);
// Retrieves the string labeled "colorName" and "hexValue",
// and converts them into javascript objects
String color = jsonObject.getString("colorName");
String hex = jsonObject.getString("hexValue");
// Adds strings from the current object to the data string
//spacing is included at the end to separate the results from
//one another
data += "n"+ "Color Number " + (i + 1) + "n"+"Color Name: " + color +
"n"+ "nHex Value : " + hex + "nnn"+ "n";
}
// Adds the data string to the TextView "results"
results.setText(data);
}
/* ============================================================ */
/* ////////////////////////// Example 2 working /////////////////////////////// */
//url https://raw.githubusercontent.com/ianbar20/JSON-Volley-Tutorial/master/Example-JSON-Files/Example-Array.JSON
/*
try {
// Retrieves first JSON object in outer array
JSONObject colorObj = response.getJSONObject(0);
// Retrieves "colorArray" from the JSON object
JSONArray colorArry = colorObj.getJSONArray("colorArray");
// Iterates through the JSON Array getting objects and adding them
//to the list view until there are no more objects in colorArray
for (int i = 0; i < colorArry.length(); i++) {
//gets each JSON object within the JSON array
JSONObject jsonObject = colorArry.getJSONObject(i);
// Retrieves the string labeled "colorName" and "hexValue",
// and converts them into javascript objects
String color = jsonObject.getString("colorName");
String hex = jsonObject.getString("hexValue");
// Adds strings from the current object to the data string
//spacing is included at the end to separate the results from
//one another
data += "n"+ "Color Number " + (i + 1) + "n"+"Color Name: " + color +
"n"+ "nHex Value : " + hex + "nnn"+ "n";
}
// Adds the data string to the TextView "results"
results.setText(data);
}
*/
// Try and catch are included to handle any errors due to JSON
catch (JSONException e) {
// If an error occurs, this prints the error to the log
e.printStackTrace();
}
}
},
// The final parameter overrides the method onErrorResponse() and passes VolleyError
//as a parameter
new Response.ErrorListener() {
@Override
// Handles errors that occur due to Volley
public void onErrorResponse(VolleyError error) {
Log.e("Volley", "Error");
}
}
);
// Adds the JSON array request "arrayreq" to the request queue
requestQueue.add(arrayreq);
}}
我的视图有一个文本视图和ListView
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp"
tools:context=".MainActivity"
android:weightSum="1">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView" />
<ListView
android:id="@+id/listv"
android:layout_width="match_parent"
android:layout_height="89dp"/>
</LinearLayout>
因此，我如何在listView中显示我的射击响应，而不是文本视图(它以预期显示响应(在同一视图中有一个文本视图和listView认为错误吗？如果我这样做：myadapter.add(结果(，应用程序崩溃。您说除了获取列表并将适配器设置为该列表之外，我不需要其他任何东西。
我认为您不太了解Adapters的主要功能。让我向您解释：
ArrayAdapter类是Adapter(从BaseAdapter延伸(，可与Arrays和Lists一起使用，并且可以使您无需手动调用getView()方法就可以使用它。要使它起作用，您需要在创建过程中传递3个参数：
1-您的context
2-列表的每一行的Layout
3-您在List或Array格式中的数据
例如
adapter=new ArrayAdapter(this, R.layout.item_layout, items);
在这种情况下，Android本身将检查列表的大小，获取所有数据并在视图的每一行中输入它们，然后以列表表单返回您。
您担心的getView()方法属于ArrayAdapter SuperClass(BaseAdapter(，并且该方法由应用程序自动管理，因此不必担心。请记住，在将其传递给适配器之前，请检查您的列表是否没有空或无空。