我們經常會在后臺線程中去做一些耗時的操作，比如去網絡取數據。但是當數據取回來，需要顯示到頁面上的時候，會遇到一些小麻煩，因為我們都知道，android的UI頁面是不允許在其他線程直接操作的。下面總結4中方法用來在線程中操作UI界面。

模擬耗時操作

private void connectNet() throws InterruptedException {Thread.sleep(2000); }

方法一：Handler

子線程中通過Handler的sendMessage（msg）發送事件：

private void method1() {new Thread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();//向Handler發送消息mHadndler.sendEmptyMessage(111);} catch (InterruptedException e) {e.printStackTrace();}}}).start(); }

方法二：View.post（Runnable）

private void method2() {myText.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {new Thread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();myText.post(new Runnable() {@Overridepublic void run() {myText.setText("聯網結束，更新UI數據");}});} catch (InterruptedException e) {e.printStackTrace();}}}).start();}}); }

方法三：Activity.runOnUiThread

與view.post類似

private void method3() {new Thread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();runOnUiThread(new Runnable() {@Overridepublic void run() {myText.setText("runOnUiThread...");}});} catch (InterruptedException e) {e.printStackTrace();}}}).start(); }

方法四：AsyncTask

private void method4() {//UI線程中執行new LoadTask().execute("www.91dota.com"); } private class LoadTask extends AsyncTask {protected void onPostExecute(String result) {myText.setText(result); //得到來自網絡的信息刷新頁面}protected String doInBackground(Object[] objects) {return "......";//后臺耗時操作} }

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示例：

附上代碼和布局

MainActivity.java

public class MainActivity extends AppCompatActivity {private TextView myText;private Handler mHadndler = new Handler() {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);myText.setText("收到消息啦..." + msg.what);}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);myText = findViewById(R.id.myTextView);}/*** 方法一：Handler*/private void method1() {new Thread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();//向Handler發送消息mHadndler.sendEmptyMessage(111);} catch (InterruptedException e) {e.printStackTrace();}}}).start();}/*** 方法二：通過View.post(Runnable)*/private void method2() {myText.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {new Thread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();myText.post(new Runnable() {@Overridepublic void run() {myText.setText("聯網結束，更新UI數據");}});} catch (InterruptedException e) {e.printStackTrace();}}}).start();}});}/*** 方法三：Activity.runOnUiThread（Runnable )*/private void method3() {runOnUiThread(new Runnable() {@Overridepublic void run() {try {//耗時操作connectNet();myText.setText("runOnUiThread...");} catch (InterruptedException e) {e.printStackTrace();}}});}/*** 方法四：AsyncTask*/private void method4() {//UI線程中執行new LoadTask().execute("www.91dota.com");}private class LoadTask extends AsyncTask {protected void onPostExecute(String result) {myText.setText(result); //得到來自網絡的信息刷新頁面}protected String doInBackground(Object[] objects) {return "......";//后臺耗時操作}}private void connectNet() throws InterruptedException {Thread.sleep(2000);} }

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><TextViewandroid:id="@+id/myTextView"android:layout_width="match_parent"android:layout_height="50dp"android:layout_margin="10dp"android:background="#dea"android:gravity="center"android:text="Hello World!" /></LinearLayout>

?

總結

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