Android：加载时进度条

Question

在Android开发中，我使用以下代码从网址加载drawable：

public Drawable getImageFromURL(String sURL) {
    Object content = null;
    try {
        URL url = new URL(sURL);
        content = url.getContent();

    } catch (Exception ex) {
        ex.printStackTrace();
    }
    InputStream is = (InputStream) content;
    return Drawable.createFromStream(is, "src");
}

但是我想在加载drawable时显示这个ProgressBar：

final AlertDialog alertDialog = new AlertDialog.Builder(this).create();
        progressBar = ProgressDialog.show(TabMenu.this, getString(R.string.name), getString(R.string.specials));
        progressBar.setIcon(R.drawable.icon_template);

我该怎么做？我在Activity的onCreate（）方法中调用了getImageFromURL（）。 谢谢你的帮助！

Answer 1

您需要在新主题中下载图像。您可以使用AsyncTask来简化此example，这也实现了进度条

Answer 2

private Handler handler = new Handler() {

    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        // do something

        switch (msg.what){
            case 1:
               //ALL FUNCTION(S) -----------------------------
               //-----------------------------------------------------
               //-----------------------------------------------------
               p_dialog.dismiss();
               break;

           // if error
           case 0:
               Toast.makeText(aktiviti.this, "Error", Toast.LENGTH_SHORT).show();
               p_dialog.dismiss();
               break;
        }
    }
};

---

ON CREATE ---------＆gt; ＆LT; ----------------

Button new_button = (Button) findViewById(R.id.new_button);

new_button.setOnClickListener(new OnClickListener() {

    public void onClick(View v) {

        p_dialog = ProgressDialog.show((activity_name).this, "", "Loading Image...");

        new Thread(new Runnable() {
            public void run() {
                processThread();
            }}).start();
        }

        private void processThread() {
            try{
                handler.sendEmptyMessage(1);
            }
            catch (Exception e){
                handler.sendEmptyMessage(0);
            }
        }
    }
});

祝你好运！