android Activity runOnUiThread() 方法的使用

轉載請標明出處：https:////www.cnblogs.com/tangZH/p/6107556.html

更多精彩文章： http://77blogs.com/?p=138

利用Activity.runOnUiThread(Runnable)把更新ui的代碼創建在Runnable中，然后在需要更新ui時，把這個Runnable對象傳給Activity.runOnUiThread(Runnable).

Runnable對像就能在ui程序中被調用。

/**

 * Runs the specified action on the UI thread. If the current thread is the UI

 * thread, then the action is executed immediately. If the current thread is

 * not the UI thread, the action is posted to the event queue of the UI thread.

 *

 * @param action the action to run on the UI thread

 */

public final void runOnUiThread(Runnable action) {

    if (Thread.currentThread() != mUiThread) {

        mHandler.post(action);

    } else {

        action.run();

    }

}

從上面的源代碼中可以看出，程序首先會判斷當前線程是否是UI線程，如果是就直接運行，如果不是則post，這時其實質還是使用的Handler機制來處理線程與UI通訊。

 

        private ProgressDialog progressDialog;
        Context mContext；

        progressDialog = new ProgressDialog(mContext); String stri = mContext.getResources().getString(R.string.Is_sending_a_request); progressDialog.setMessage(stri); progressDialog.setCanceledOnTouchOutside(false); progressDialog.show(); new Thread(new Runnable() { public void run() { try { ((Activity)mContext).runOnUiThread(new Runnable() { public void run() { progressDialog.dismiss(); String s1 = mContext.getResources().getString(R.string.send_successful); Toast.makeText(mContext, s1, Toast.LENGTH_LONG).show(); } }); } catch (final Exception e) { ((Activity)mContext).runOnUiThread(new Runnable() { public void run() { progressDialog.dismiss(); String s2 = mContext.getResources().getString(R.string.Request_add_buddy_failure); Toast.makeText(mContext, s2 + e.getMessage(), Toast.LENGTH_LONG).show(); } }); } } }).start();

用這種方式創建ProgressDialog就比較方便，或者刷新adapter也比使用Thread+Handler方便。

如果不是在activity中創建，需要在前面加上((Activity)mContext). 。