【发布时间】：2021-07-31 03:47:37
【问题描述】：
我找不到问题所在。 Logcat 说：
“引起：java.lang.ClassCastException： com.example.project.model.DataModel 不能转换为 java.util.ArrayList"
我尝试了不同的解决方案，但都没有奏效：
- 可打包
- @SuppressWarning
谁能告诉我我的代码有什么问题？
DataModel.Java
public class DataModel implements Serializable {
ArrayList<FeaturesModel> features;
String title;
public DataModel(ArrayList<FeaturesModel> featuresModels, String s) {
features =featuresModels;
title=s;
}
public ArrayList<FeaturesModel> getFeatures() {
return features;
}
public void setFeatures(ArrayList<FeaturesModel> features) {
this.features = features;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
TableActivity.Java
public class TableActivity extends AppCompatActivity {
ArrayList<DataModel> dataModelList = new ArrayList<>();
EditText edtTableCount;
Button btnCreateTable;
TableAdapter adapter;
RecyclerView recylerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_table);
recylerView = findViewById(R.id.rvTables);
btnCreateTable = findViewById(R.id.btnCreateTable);
btnCreateTable.setOnClickListener(view -> {
edtTableCount = findViewById(R.id.edtTableCount);
String getTableCount = edtTableCount.getText().toString();
int tableCount = Integer.parseInt(getTableCount);
for (int i = 0; i< tableCount; i++){
dataModelList.add(new DataModel(new ArrayList<>(),"Masa " + i));
}
edtTableCount.setVisibility(GONE);
btnCreateTable.setVisibility(GONE);
recylerView.setVisibility(View.VISIBLE);
});
setAdapter();
}
public void setAdapter(){
CustomItemClickListener listener = (v, position) -> {
Intent i = new Intent(TableActivity.this,DetailsActivity.class);
i.putExtra("position",position);
i.putExtra("dataModelList",dataModelList);
startActivity(i);
};
adapter = new TableAdapter(this,dataModelList,listener);
recylerView.setAdapter(adapter);
}
}
DetailsActivity.Java
public class DetailsActivity extends AppCompatActivity {
ArrayList<DataModel> dataModelList = new ArrayList<>();
DataModel dataModel;
EditText edtDeviceInfo, edtBrand, edtModel, edtProcessor, edtRam, edtGraphicCard, edtOperationSystem, edtHardDisc, edtPrograms, edtDescription;
Button btnAdd;
int position = 0;
String keyDeviceInfo = "keyDeviceInfo",
keyBrand = "keyBrand",
keyModel = "keyModel",
keyProcessor = "keyModel",
keyRam = "keyModel",
keyGraphicCard = "keyModel",
keyOperationSystem = "keyModel",
keyHardDisc = "keyModel",
keyPrograms = "keyModel",
keyDescription = "keyModel"
;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_details);
edtDeviceInfo = findViewById(R.id.edtDeviceInfo);
edtBrand = findViewById(R.id.edtBrand);
edtModel = findViewById(R.id.edtModel);
edtProcessor = findViewById(R.id.edtProcessor);
edtRam = findViewById(R.id.edtRam);
edtGraphicCard = findViewById(R.id.edtGraphicCard);
edtOperationSystem = findViewById(R.id.edtOperationSystem);
edtHardDisc = findViewById(R.id.edtHardDisc);
edtPrograms = findViewById(R.id.edtPrograms);
edtDescription = findViewById(R.id.edtDescription);
btnAdd = findViewById(R.id.btnAdd);
dataModelList = (DataModel) getIntent().getSerializableExtra("dataModelList");
position = getIntent().getIntExtra("position",0);
dataModel = dataModelList.get(position);
btnAdd.setOnClickListener(view -> {
setInformations(
edtDeviceInfo.getText().toString(),
edtBrand.getText().toString(),
edtModel.getText().toString(),
edtProcessor.getText().toString(),
edtRam.getText().toString(),
edtGraphicCard.getText().toString(),
edtOperationSystem.getText().toString(),
edtHardDisc.getText().toString(),
edtPrograms.getText().toString(),
edtDescription.getText().toString()
);
});
}
public void setInformations(String deviceInfo, String brand, String model, String processor, String ram, String graphiccard, String operationsystem,
String harddisc, String programs, String description){
edtDeviceInfo.setText(deviceInfo);
edtBrand.setText(brand);
edtModel.setText(model);
edtProcessor.setText(processor);
edtRam.setText(ram);
edtGraphicCard.setText(graphiccard);
edtOperationSystem.setText(operationsystem);
edtHardDisc.setText(harddisc);
edtPrograms.setText(programs);
edtDescription.setText(description);
}
}
【问题讨论】：
-
您正在向 Intent 添加单个
DataModel项目，但试图在接收器Activity中获取ArrayList<DataModel>- 错误告诉您这一点。只需转换为(DataModel)即可（无需额外添加位置）。注意 - 在您的问题中添加代码 sn-ps 通常是一种很好的做法，而不是指向代码屏幕截图的链接。 -
您正在通过意图传递
dataModelList.get(position)-- 单个 DataModel 对象，并在接收者活动中检索ArrayList<DataModel>；而不是DataModel。你需要什么数据？整个列表还是单个对象？基于此，将适当的值传递给意图。 -
抱歉，我没看懂代码怎么写清楚。我试了几次，但代码搞砸了。让我解释一下我需要什么。我正在使用 recyclerview 在应用程序中创建表。之后，我做了一个活动来设置表格的详细信息。示例：表 0 -> cpu - gpu - os - 等。我想检查位置以找到我在桌子上的哪个位置。然后我会为每张桌子设置一些额外的功能。我会尝试将代码放入主评论中。