android - 来自 ListView 的 setOnItemClickListener 的 PopupWindow 未显示

Question

我试图通过 ListView 的 setOnItemClickListener 显示 PopupWindow，但没有显示任何内容。

我做错了什么？

谢谢

HomeActivity.java

public class HomeActivity extends BaseActivity {

    /* ... */

    PopupWindow popUp;

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        /* ... */

        listView.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id){                

                LinearLayout layout;
                TextView tv;
                LayoutParams params;

                popUp = new PopupWindow(HomeActivity.this);
                layout = new LinearLayout(HomeActivity.this);
                tv = new TextView(HomeActivity.this);
                params = new LayoutParams(LayoutParams.WRAP_CONTENT,
                  LayoutParams.WRAP_CONTENT);
                layout.setOrientation(LinearLayout.VERTICAL);
                tv.setText("Hi this is a sample text for popup window");
                tv.setTextColor(Color.RED);
                tv.setTextSize(50);
                layout.addView(tv, params);
                popUp.setContentView(layout);
                popUp.showAtLocation(findViewById(R.id.base_layout), Gravity.CENTER, 500, 500);                

            }

        });

        /* ... */

    }
}

BaseActivity.java

public abstract class BaseActivity extends ListActivity{

    private EditText search_field;

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.base);
    }
}

base.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/base_layout" >

    <!-- ... -->

</RelativeLayout>

Answer 1

它在我使用时显示

layout = new LinearLayout(HomeActivity.this);
/* ... */
popUp = new PopupWindow(layout,LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT);
popUp.showAtLocation(findViewById(R.id.base), Gravity.CENTER, 500, 500);   

代替

popUp = new PopupWindow(HomeActivity.this);
layout = new LinearLayout(HomeActivity.this);
/* ... */
popUp.setContentView(layout);
popUp.showAtLocation(findViewById(R.id.base_layout), Gravity.CENTER, 500, 500);