主线程更新UI与Only the original thread that created a view hierarchy can touch its views.

最新推荐文章于 2024-12-16 18:38:12 发布

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本文介绍了一种在Android应用开发中解决子线程更新UI的方法。通过使用Handler、View.post、runOnUiThread等机制，可以避免报错“Only the original thread that created a view hierarchy can touch its views”，并给出了具体示例。

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报错：

Only the original thread that created a view hierarchy can touch its views.

原因：

子线程中不能更新ui操作

主线程更新UI方式：

更新UI方法一：handler.post
更新UI方法二：view.post
更新UI方法三：runOnUiThread
更新UI方法四：handler.handleMessage

示例：

public class ThreadActivity extends FragmentActivity {

    /*更新UI方法四：handler.handleMessage*/
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            switch (msg.what) {
                case 0:
                    Log.e("111", "开始下载");
                    break;
                case 1:
                    Log.e("111", "设置图片");
                    mIv.setImageBitmap((Bitmap) msg.obj);
                    Log.e("111", "handler.handleMessage为：" + Looper.getMainLooper().getThread());//Thread[main,5,main]
                    Log.e("111", "handler.handleMessage 名称为：" + Thread.currentThread().getName());//main
                    break;
                case 2:
                    Log.e("111", "设置完毕");
                    break;
            }

        }
    };

    private ImageView mIv;

    private String path = "https://github.com/Ablexq/MyTabs/raw/master/pic/a.jpg";

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_thread);

        mIv = ((ImageView) this.findViewById(R.id.iv));

        Log.e("111", "主线程（UI线程）为：" + Looper.getMainLooper().getThread());//Thread[main,5,main]
        Log.e("111", "主线程（UI线程）名称为：" + Thread.currentThread().getName());//main

        new Thread(new Runnable() {//子线程

            @Override
            public void run() {

                //下载前
                handler.sendEmptyMessage(0);

                Bitmap bm = null;
                try {
                    HttpURLConnection huc = (HttpURLConnection) new URL(path).openConnection();
                    huc.connect();

                    if (huc.getResponseCode() == 200) {
                        bm = BitmapFactory.decodeStream(huc.getInputStream());
                    }


                    //设置图片
                    Message message = Message.obtain();
                    message.obj = bm;
                    message.what = 1;
                    handler.sendMessage(message);

                    //设置图片后
                    handler.sendEmptyMessage(2);

                } catch (IOException e) {
                    e.printStackTrace();
                }

                Log.e("111", "new Thread线程为：" + Thread.currentThread());//Thread[Thread-5,5,main]
                Log.e("111", "new Thread线程 名称为：" + Thread.currentThread().getName());//Thread-5

                final Bitmap finalBm = bm;

                /*更新UI方法一：handler.post*/
//                handler.post(new Runnable() {
//                    @Override
//                    public void run() {
//                        Log.e("111", "handler.post线程为：" + Thread.currentThread());//Thread[main,5,main]
//                        Log.e("111", "handler.post线程 名称为：" + Thread.currentThread().getName());//main
//                        mIv.setImageBitmap(finalBm);
//                    }
//                });


                /*更新UI方法二：view.post*/
//                mIv.post(new Runnable() {
//                    @Override
//                    public void run() {
//                        Log.e("111", "view.post线程为：" + Thread.currentThread());//Thread[main,5,main]
//                        Log.e("111", "view.post线程 名称为：" + Thread.currentThread().getName());//main
//                        mIv.setImageBitmap(finalBm);
//                    }
//                });

                /*更新UI方法三：runOnUiThread*/
//                runOnUiThread(new Runnable() {
//                    @Override
//                    public void run() {
//                        Log.e("111", "runOnUiThread线程为：" + Thread.currentThread());//Thread[main,5,main]
//                        Log.e("111", "runOnUiThread线程 名称为：" + Thread.currentThread().getName());//main
//
//                        mIv.setImageBitmap(finalBm);
//                    }
//                });

            }
        }).start();

    }
}