Question

我不知道我在这里做错了什么。我已按照教程进行操作，但我的值最终为空。

将值传递给意图

ListView lvItems = (ListView) view.findViewById(R.id.lvDashboardCompleted);
        lvItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {


            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                //Toast shows the id over here
                Intent intent = new Intent(getActivity(), categoryActivity.class);
                intent.putExtra("CATEGORY_ID", id);
                startActivity(intent);
            }
        });

从意图中恢复价值

public class categoryActivity extends AppCompatActivity {

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

        String recevied_cat_id = getIntent().getStringExtra("CATEGORY_ID");

        Context context = getApplicationContext();
        CharSequence text = recevied_cat_id;
        int duration = Toast.LENGTH_SHORT;

        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    }
}

Answer 1

改为使用String recevied_cat_id = getIntent().getLongExtra("CATEGORY_ID", defaultLongValue);。

Answer 2

尝试替换onCreate方法。问题是什么？由于@ARiF已正确突出显示，您从Intent传递的时间很长，但在您的方法中，您正在检索字符串。

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getSupportActionBar().hide();
        setContentView(R.layout.activity_category);

        Long recevied_cat_id = getIntent().getLongExtra("CATEGORY_ID", 1L);

        Context context = getApplicationContext();
        String strLong = Long.toString(recevied_cat_id);
        CharSequence text = strLong;
        int duration = Toast.LENGTH_SHORT;

        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    }

来自Intent的值未显示

2 个答案: