Question

我想将一些ImageView添加到RelativeLayout视图。

我使用的代码如下：

Thread thread = new Thread(new Runnable() {
        ArrayList<ImageView> icons = new ArrayList<ImageView>();

        @Override
        public void run() {
            for (int i = 0; i < 20; i++) {

                ImageView imageView1 = new ImageView(G.context);
                imageView1.setImageResource(R.drawable.music_icon);
                imageView1.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,
                        RelativeLayout.LayoutParams.WRAP_CONTENT));
                imageView1.getLayoutParams().width = (int) convertDpToPixel(20);
                imageView1.getLayoutParams().height = (int) convertDpToPixel(20);

                icons.add(imageView1);

                Log.i("LOG", "Icons Size: " + icons.size());
                Log.i("LOG", "I: " + i);

                relativeLayout.addView(icons.get(i));

                icons.get(i).startAnimation(animationMusic);

                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    });
    thread.start();

第一次循环运行正常，但第二次出现错误：

relativeLayout.addView(icons.get(i));

问题出在哪里？

Answer 1

一个主要问题是从后台线程操纵视图（例如添加视图）。您可以通过使用Android的AsyncTask对象获取类似的异步行为，并从onPostExecute方法执行任何UI操作。

如果不了解您正在做的事情，很难找到适合您的解决方案。我主要指出了代码的主要问题。

尝试以在Android环境中可能更好的方式重写代码：

public void addImageViews() {
    for(int i = 0; i < 20; i++) {
        asyncAdd(i, G.context);
    }
}

protected void asyncAdd(final int index, final Context c) {
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                Thread.sleep(3000 * index);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            relativeLayout.addView(generateImageView(c));
        }

    }.execute();
}

protected ImageView generateImageView(Context c) {
    ImageView imageView1 = new ImageView(c);
    imageView1.setImageResource(R.drawable.music_icon);
    imageView1.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT));
    imageView1.getLayoutParams().width = (int) convertDpToPixel(20);
    imageView1.getLayoutParams().height = (int) convertDpToPixel(20);
    return imageView1;
}

我怎样才能将一些ImageView添加到relativeLayout

1 个答案: