Question

我正在开发一个应用程序，我正在构建一个评论列表。这个想法是用户可以添加注释，并在ListView中查看它们。问题是ListView中项目的文本颜色是浅灰色（难以阅读）而不是黑色，除非使用已有的评论列表重新启动应用程序。换句话说，只有在动态添加注释时，文本才是灰色的。你们知道为什么会这样吗？我的代码如下：

    previousCommentsList = (ListView) findViewById(R.id.previous_comments_list);
    commentsArrayList = new ArrayList<String>();
    for (Comment comment : DrawView.comments) {         
        commentsArrayList.add(comment.text);
    }
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, commentsArrayList);
    previousCommentsList.setAdapter(adapter);

    saveCommentButton = (Button) findViewById(R.id.save_comment_button);
    saveCommentButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {
            EditText commentEditText = (EditText) findViewById(R.id.comment_edittext);

            // Add the comment
            Comment comment = new Comment();
            comment.text = commentEditText.getText().toString();
            DrawView.comments.add(comment);

            Toast.makeText(getApplicationContext(), "Comment saved", Toast.LENGTH_SHORT).show();

            commentsArrayList = new ArrayList<String>();
            for (Comment comment2 : DrawView.comments) {            
                commentsArrayList.add(comment2.text);
            }
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, commentsArrayList);
            previousCommentsList.setAdapter(adapter);
            // Probably using both notifyDataSetChanged() and invalidate() is redundant
            adapter.notifyDataSetChanged();
            previousCommentsList.invalidate();
        }
    });

Answer 1

我有类似的问题。在我的情况下，它是由使用应用程序上下文而不是活动上下文引起的（在我看来也是这种情况 - new ArrayAdapter<String>(getApplicationContext(),...);）。在我看来，正确的配色方案与活动上下文相关联，而不是与应用程序上下文相关联。

希望这会有所帮助。

另见Use android.R.layout.simple_list_item_1 with a light theme

Answer 2

我注释掉了代码的某些部分，这似乎有点不必要。我不确定与Comment类相关的代码。在这种情况下，至少它似乎是多余的。

previousCommentsList = (ListView) findViewById(R.id.previous_comments_list);

commentsArrayList = new ArrayList<String>();
for (Comment comment : DrawView.comments) {         
    commentsArrayList.add(comment.text);
}

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, commentsArrayList);
previousCommentsList.setAdapter(adapter);

saveCommentButton = (Button) findViewById(R.id.save_comment_button);

saveCommentButton.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View view) {
        EditText commentEditText = (EditText) findViewById(R.id.comment_edittext);


        // COMMENT: Is creating a comment object really neccessary, if it only serves the purpose of saving a text ?


        Comment comment = new Comment();
        comment.text = commentEditText.getText().toString();
        // DrawView.comments.add(comment); COMMENT: -> Is this neccessary? 

        Toast.makeText(getApplicationContext(), "Comment saved", Toast.LENGTH_SHORT).show();

        // commentsArrayList = new ArrayList<String>();
        // for (Comment comment2 : DrawView.comments) {            
        commentsArrayList.add(comment.text);
        // }

        // ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, commentsArrayList);
        // previousCommentsList.setAdapter(adapter);

        adapter.notifyDataSetChanged();

    }
});

为什么动态生成的ListView文本是灰色的？

2 个答案: