java - android kitkat 中的类转换异常

Question

我在 Android Lollipop 上试用了该应用程序，它工作正常，但在 kitkat 上测试时显示错误:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.yourpackage/com.yourpackage.category}: java.lang.ClassCastException: java.lang.Object[] cannot be cast to com.itmightys.www.ulhasnagar.Cat[]

这是我的类别类。在此先感谢您的帮助

public class category extends AppCompatActivity {


    GridView gv;
    Context context;
    private CategoryAdapter adapter;
    MyDBHandler dbHandler;
    private ActionBarDrawerToggle listener;
    private DrawerLayout drawerLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_category);
        Navigation navigation = new Navigation(this);
        drawerLayout=(DrawerLayout)findViewById(R.id.drawer_layout);
        Intent intent=getIntent();
        Cat[] categories=(Cat[])intent.getSerializableExtra("categories");

        gv=(GridView) findViewById(R.id.gridView1);
        adapter=new CategoryAdapter(this);
        adapter.initializedata(categories);
        gv.setAdapter(adapter);


        //nav drawer animate
        listener = new ActionBarDrawerToggle(this,drawerLayout,R.string.opendrw,R.string.closedrw){
            @Override
            public void onDrawerOpened(View drawerView) {
                //Toast.makeText(context,"Opened",Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                //Toast.makeText(MainActivity.this,"Closed",Toast.LENGTH_SHORT).show();
            }
        };
        drawerLayout.setDrawerListener(listener);
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }


@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    listener.syncState();
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (listener.onOptionsItemSelected(item))
    {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_category, menu);
        return true;
    }



}

这是我的猫类

public class Cat implements Serializable{
private int category_id;
private String category_name;
private int hassub;
private String category_img;

//empty constructor
public Cat(){

}
//constructor

public Cat(int category_id, String category_name, int hassub, String category_img) {
    this.category_id = category_id;
    this.category_name = category_name;
    this.hassub = hassub;
    this.category_img = category_img;
}

//setter


public void setCategory_id(int category_id) {
    this.category_id = category_id;
}

public void setCategory_img(String category_img) {
    this.category_img = category_img;
}

public void setCategory_name(String category_name) {
    this.category_name = category_name;
}

public void setHassub(int hassub) {
    this.hassub = hassub;
}


//getters

public int getCategory_id() {
    return category_id;
}

public String getCategory_img() {
    return category_img;
}

public String getCategory_name() {
    return category_name;
}

public int getHassub() {
    return hassub;
}
}

我正在从 MainActivity 调用 Category 这是代码:

public class MainActivity extends AppCompatActivity {
        protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    ImageView directory=(ImageView) findViewById(R.id.imageView4);
     directory.setClickable(true);
            directory.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {

                    final Cat cat[];
                    cat = retrievecat();
                    Intent intent = new Intent(MainActivity.this, category.class);
                    intent.putExtra("categories", cat);
                    startActivity(intent);
                }
            });
}
}

Answer 1

也许我走错了，但我需要展示这段代码，所以不好发表评论。自 Lollipop 以来，可序列化和数组发生了一些变化，所以我猜你不能转换为具有较低 API 的数组。您可以尝试像这样复制数组:

Object[] arrayObject = (Object[]) intent.getSerializableExtra("categories");  

Cat[] catArray = Arrays.copyOf(arrayObject , arrayObject.length, Cat[].class);