[英]How to Call Method in Activity From Other Class not Activity in Android?
[英]How to use method from other class in Activity
我的Android應用程序中有兩個Activity:
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Connection.Response response = new Second().get();
}
}
和:
public class Second extends Activity {
Connection.Response response = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
get();
}
public Connection.Response get()
{
try {
response = Jsoup.connect("http://example.com").execute();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
第二項活動正常-我在類中使用了get方法,這很好,但是如果我打開MainActivity,則會出現錯誤:
08-25 19:31:30.764: E/AndroidRuntime(999): FATAL EXCEPTION: main
08-25 19:31:30.764: E/AndroidRuntime(999): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.js/com.example.js.MainActivity}: android.os.NetworkOnMainThreadException
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread.access$600(ActivityThread.java:122)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.os.Handler.dispatchMessage(Handler.java:99)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.os.Looper.loop(Looper.java:137)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread.main(ActivityThread.java:4340)
08-25 19:31:30.764: E/AndroidRuntime(999): at java.lang.reflect.Method.invokeNative(Native Method)
08-25 19:31:30.764: E/AndroidRuntime(999): at java.lang.reflect.Method.invoke(Method.java:511)
08-25 19:31:30.764: E/AndroidRuntime(999): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-25 19:31:30.764: E/AndroidRuntime(999): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-25 19:31:30.764: E/AndroidRuntime(999): at dalvik.system.NativeStart.main(Native Method)
08-25 19:31:30.764: E/AndroidRuntime(999): Caused by: android.os.NetworkOnMainThreadException
08-25 19:31:30.764: E/AndroidRuntime(999): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
08-25 19:31:30.764: E/AndroidRuntime(999): at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
08-25 19:31:30.764: E/AndroidRuntime(999): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
08-25 19:31:30.764: E/AndroidRuntime(999): at java.net.InetAddress.getAllByName(InetAddress.java:220)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:71)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:351)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:86)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:308)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpEngine.connect(HttpEngine.java:303)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:282)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:232)
08-25 19:31:30.764: E/AndroidRuntime(999): at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:80)
08-25 19:31:30.764: E/AndroidRuntime(999): at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:425)
08-25 19:31:30.764: E/AndroidRuntime(999): at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:410)
08-25 19:31:30.764: E/AndroidRuntime(999): at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:164)
08-25 19:31:30.764: E/AndroidRuntime(999): at com.example.js.Second.get(Second.java:27)
08-25 19:31:30.764: E/AndroidRuntime(999): at com.example.js.MainActivity.onCreate(MainActivity.java:15)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.Activity.performCreate(Activity.java:4465)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
08-25 19:31:30.764: E/AndroidRuntime(999): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
08-25 19:31:30.764: E/AndroidRuntime(999): ... 11 more
Second.java:27:響應= Jsoup.connect(“ http://example.com ”).execute();
MainActivity.java:15:Connection.Response響應= new Second()。get();
我該怎么做?
您不能在主線程上訪問網絡。 這是為了防止您的UI呈現被長時間運行的網絡調用所阻塞。 您需要將網絡邏輯放在其自己的線程中。 我建議使用AsyncTask 。
另外,您不應以此方式創建自己的活動。 如果您需要兩個活動進行通信。 使用startActivityForResult和setResult使用Intent的數據包來回傳遞數據。
從外觀上看,您純粹是在使用Second Activity進行數據檢索。 您應該考慮在服務中執行此操作。 您仍然需要處理Service中的線程(或者您可以使用IntentService)
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