android - gridview 点击item的时候 SetImageResource 更换imageview失败-PHP中文网问答

如题，我想通过点击gridview下的item而更改他的imageview。不过点击了没有反应。有没有大神知道怎么回事？

public class table extends AppCompatActivity implements AdapterView.OnItemClickListener{

GridView gridView;
my_adapter my_adapter;
String table_names[]={"1a","1b","1c","1d","2a","2b","2c","2d","3a","3b","3c","3d"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_table);

    gridView=(GridView)findViewById(R.id.gridview);
    my_adapter=new my_adapter(this,table_names);
    gridView.setAdapter(my_adapter);
    gridView.setOnItemClickListener(this);
}

@Override
public void onItemClick(final AdapterView adapterView, final View view, final int i, long l) {

    new AlertDialog.Builder(this)
            .setTitle("Table number: "+adapterView.getItemAtPosition(i).toString())
            .setMessage("Open Table？")
            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    my_adapter.change_img(); // 更换新的图片

                }
            })
            .setNegativeButton("No", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    my_adapter.change_img2(); // 更换回原来的图片
                }
            })
            .show();
}
}

class my_adapter extends BaseAdapter{

ImageView imageView;
LayoutInflater inflater=null;
Context ctx;
String table_names[];
ArrayList store_table_no;

my_adapter(Context ctx, String table_names[]){
    this.ctx=ctx;
    this.table_names=table_names;
    store_table_no=new ArrayList();
    for (int i=0;i


single.xml

@Override public void onItemClick(final AdapterView<?> adapterView, final View view, final int i, long l) { // 找到被点击的item中的iamgeView final View imageView = view.findViewById(R.id.imageView); new AlertDialog.Builder(this) .setTitle("Table number: "+adapterView.getItemAtPosition(i).toString()) .setMessage("Open Table？") .setPositiveButton("Yes", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { if(imageView != null && (imageView instanceOf ImageView)) {// 检查防止报错 ((ImageView)imageView).setImageResource(R.drawable.table_full); } } }) .setNegativeButton("No", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { //同上 } }) .show(); } }