Question

I want to use a menu to send a message to handler. And handler started a thread to update from server.

However, when I tested my app, I closed down the server and pressed the menu. The android app is blocked in the menu which should not happen because the menu just send a message. Therefore my UI was blocked.

Here is the code

final Handler messageHandler = new Handler() {
    public void handleMessage(Message msg) {

        switch (msg.arg2) {
        case 0:
            int total = msg.arg1;
            progressDialog.setProgress(total);
            if (total >= progressDialog.getMax()) {
                // 取消Dialog并且置0
                dismissDialog(PROGRESS_DIALOG);
                progressDialog.setProgress(0);
                Toast.makeText(CardProcessView.this, "下载完成",
                        Toast.LENGTH_SHORT).show();
                initData();
            }
            break;
        case 1:
            updatabase();
            break;
        }

    }
};


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case 0:
        Message message = new Message();
        message.arg2 = 1;
        messageHandler.sendMessage(message);
        break;
    default:
        Log.d("update", "未更新");
    }
    return true;
}


protected void updatabase() {

    new Thread(updateRunable ).run();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    menu.add("更新操作向导");
    return true;
}

I can’t find my answer. Thank you for everyone.

Answer 1

you need change:

new Thread(updateRunable ).run();

to:

new Thread(updateRunable ).start();

thread.run() just invoke the thread’s run method, dont start the method in a new thread, you need invoke thread.start() to make a thread and invoke run method in this new thread.