问：我在使用ListView时遇到麻烦。每当我按列表中的项目时，它总是使我返回登录页面。它应该转到详细信息页面。
家庭活动
package com.example.kun.carcarkila;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
import com.amigold.fundapter.BindDictionary;
import com.amigold.fundapter.FunDapter;
import com.amigold.fundapter.extractors.StringExtractor;
import com.amigold.fundapter.interfaces.DynamicImageLoader;
import com.kosalgeek.android.json.JsonConverter;
import com.kosalgeek.genasync12.AsyncResponse;
import com.kosalgeek.genasync12.PostResponseAsyncTask;
import com.nostra13.universalimageloader.core.ImageLoader;
import java.io.Serializable;
import java.util.ArrayList;
public class HomeActivity extends AppCompatActivity implements AsyncResponse, AdapterView.OnItemClickListener {
final String LOG = "HomeActivity";
private ArrayList<Product> productList;
private ListView lvProduct;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ImageLoader.getInstance().init(UILConfig.config(HomeActivity.this)); // Do it on Application start
PostResponseAsyncTask taskRead = new PostResponseAsyncTask(HomeActivity.this, this);
taskRead.execute("http://10.0.2.2/carkila/product.php");
}
@Override
public void processFinish(String s) {
productList = new JsonConverter<Product>().toArrayList(s, Product.class);
BindDictionary<Product> dict = new BindDictionary<Product>();
dict.addDynamicImageField(R.id.ivImg, new StringExtractor<Product>() {
@Override
public String getStringValue(Product item, int position) {
return item.img;
}
}, new DynamicImageLoader() {
@Override
public void loadImage(String url, ImageView imageView) {
ImageLoader.getInstance().displayImage(url, imageView); // Default options will be used
}
});
dict.addStringField(R.id.tvCarModel, new StringExtractor<Product>() {
@Override
public String getStringValue(Product item, int position) {
return "Car Model: " + item.Car_Model;
}
});
dict.addStringField(R.id.tvCarType, new StringExtractor<Product>() {
@Override
public String getStringValue(Product item, int position) {
return "Car Type: " + item.Car_Type;
}
});
dict.addStringField(R.id.tvCapacity, new StringExtractor<Product>() {
@Override
public String getStringValue(Product item, int position) {
return "Capacity: " + item.Capacity;
}
});
FunDapter<Product> adapter = new FunDapter<>(
HomeActivity.this, productList, R.layout.layout_list, dict);
lvProduct = (ListView)findViewById(R.id.lvProduct);
lvProduct.setAdapter(adapter);
lvProduct.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Product selectedProduct = productList.get(position);
Intent in = new Intent(HomeActivity.this, DetailActivity.class);
in.putExtra("product", (Serializable) selectedProduct);
startActivity(in);
}
}
详细活动
package com.example.kun.carcarkila;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import com.nostra13.universalimageloader.core.ImageLoader;
public class DetailActivity extends AppCompatActivity {
TextView tvCarModel, tvCarType, tvCapacity;
ImageView ivImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
ImageLoader.getInstance().init(UILConfig.config(DetailActivity.this));
Product product = (Product) getIntent().getSerializableExtra("product");
tvCarModel = (TextView)findViewById(R.id.tvCarModel);
tvCarType = (TextView)findViewById(R.id.tvCarType);
tvCapacity = (TextView)findViewById(R.id.tvCapacity);
ivImage = (ImageView)findViewById(R.id.ivImage);
if(product != null){
tvCarModel.setText(product.Car_Model);
tvCarType.setText(product.Car_Type);
tvCapacity.setText(product.Capacity);
ImageLoader.getInstance().displayImage(product.img, ivImage);
}
}
}
产品类别
package com.example.kun.carcarkila;
import com.google.gson.annotations.SerializedName;
public class Product {
@SerializedName("Car_No")
public int Car_No;
@SerializedName("Car_Model")
public String Car_Model;
@SerializedName("Car_Type")
public String Car_Type;
@SerializedName("Capacity")
public int Capacity;
@SerializedName("img")
public String img;
}
错误 是 java.lang.ClassCastException：com.example.kun.carcarkila.Product无法转换为java.io.Serializable
答：您的当前活动已崩溃，因为您的产品类不可序列化，因此这就是为什么出现最后一个活动（即登录活动）的原因。
您需要在Product类上实现Serializable接口。
产品类的第一行将如下所示。
公共类产品实现Serializable
